Yavuz Group - User contributions [en]

File:Green zach.png

2018-11-11T17:53:01Z

Karpel:

Journal Club

2018-05-24T20:17:27Z

Karpel: fix links

'''5/23/18:'''
{| class="wikitable sortable"
|-
! Journal Name !! Article Title !! Description
|-
| Optica || [https://www.osapublishing.org/optica/abstract.cfm?uri=optica-4-12-1526 Endlessly adiabatic fiber with a logarithmic refractive index distribution] || Theoretical discussion and experimental realization of making tapered fibers with very short taper length and low losses.
|-
| Optica || [https://www.osapublishing.org/optica/abstract.cfm?uri=optica-5-3-279 Microresonator isolators and circulators based on the intrinsic nonreciprocity of the Kerr effect] || The Kerr effect causes energy level splitting between CW and CCW modes in microresonators, allowing them to act as an optical isolator. Good references to coupling to the spheres, mode structure, and passive locking.
|-
| Physical Review A || [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.012131 Quantum work in the Bohmian framework] || A description of work in quantum mechanics using Bohmian ideas that is usable with thermodynamics.
|-
| Physical Review A || [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.013402 Dynamics of tunneling ionization using Bohmian mechanics] || Explores tunneling ionization using ideas from Bohmian mechanics.
|-
| Physical Review A || [https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.011801 Pulse growth dynamics in laser mode locking] || A theoretical and numerical analysis of pulse formation in a mode-locked laser.
|-
| Journal Name || [[URL|Title]] || Description.
|-

|}

'''6/21/17:'''
{| class="wikitable sortable"
|-
! Journal Name !! Article Title !! Description
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n5/full/nphoton.2017.58.html Fast silicon photodiodes] || Interesting summary of photodiode technology and limitations. Can response time be increased without sacrificing sensitivity?
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n4/full/nphoton.2017.32.html Spatial beam self-cleaning in multimode fibres] || The Kerr effect caused by high intensity beams can result in more light coupling into the fundamental mode of a multi-mode fiber, causing minimal beam speckling at the output.
|-
| Science || [http://science.sciencemag.org/content/356/6340/837 Quantum sensing with arbitrary frequency resolution] || NV centers in diamond are used to detect the frequency of oscillating magnetic fields with submillihertz resolution.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.223605 Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities] || By coupling light into a cavity with an extremely small mode volume, nonlinear optical effects can be observed with very small numbers of photons.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.243201 Ultrafast Magnetization of a Dense Molecular Gas with an Optical Centrifuge] || A new technique allows for magnetization of much denser gases than was previously possible.
|-
| Journal of Computational Physics || [http://www.sciencedirect.com/science/article/pii/S0021999116306301 Constructing non-reflecting boundary conditions using summation-by-parts in time] || An alternate technique for constructing non-reflecting boundaries, supposedly simpler than current techniques such as perfectly-matched layers (PMLs).
|-
| Nature Communications || [https://www.nature.com/articles/ncomms15610 Harnessing speckle for a sub-femtometer resolved broadband wavemeter and laser stabilization] || They demonstrate speckle-pattern based wavemeter with about 1 MHz frequency resolution
|-
| Nature Communications || [https://www.nature.com/articles/ncomms15849?WT.feed_name=subjects_physical-chemistry Observing electron localization in dissociating H2+ molecule in real time] || They use pump-probe technique with CEP stabilized ~5 fs long pulses to probe dissociation dynamics of H2+ in femtosecond time scales
|-
| Journal of the Optical Society of America A || [https://www.osapublishing.org/abstract.cfm?uri=cleo_qels-2017-FTu3D.2&origin=search Raman-assisted broadband Kerr frequency comb generation in AlN-on-sapphire microresonators] || Four wave mixing is used in a AlN film to build a frequency comb spanning 1.2-2.2 um
|-
| Nature Communications || [https://www.nature.com/articles/ncomms1984 Quantifying the magnetic nature of light emission] || Light emitted from Europium ions is decomposed into parts originating from electric dipole transitions and magnetic dipole transitions
|-
| Optics Express || [https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-25-11-12935&id=367108 Straightforward method to measure optomechanically induced transparency] || Optomechanically induced transparency is demonstrated without the use of a homodyne field
|-
| arxiv || [https://arxiv.org/pdf/1712.00655.pdf Dark state optical lattice with sub-wavelength spatial structure] || Experimental realization of an optical lattice for cold atoms with
sub-wavelength spatial structure

|}

Journal Club

2018-05-24T20:16:22Z

Karpel: add papers

'''5/23/18:'''
{| class="wikitable sortable"
|-
! Journal Name !! Article Title !! Description
|-
| Optica || [https://www.osapublishing.org/optica/abstract.cfm?uri=optica-4-12-1526 Endlessly adiabatic fiber with a logarithmic refractive index distribution] || Theoretical discussion and experimental realization of making tapered fibers with very short taper length and low losses.
|-
| Optica || [https://www.osapublishing.org/optica/abstract.cfm?uri=optica-5-3-279 Microresonator isolators and circulators based on the intrinsic nonreciprocity of the Kerr effect] || The Kerr effect causes energy level splitting between CW and CCW modes in microresonators, allowing them to act as an optical isolator. Good references to coupling to the spheres, mode structure, and passive locking.
|-
| Physical Review A || [[https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.012131|Quantum work in the Bohmian framework]] || A description of work in quantum mechanics using Bohmian ideas that is usable with thermodynamics.
|-
| Physical Review A || [[https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.013402|Dynamics of tunneling ionization using Bohmian mechanics]] || Explores tunneling ionization using ideas from Bohmian mechanics.
|-
| Physical Review A || [[https://journals.aps.org/pra/abstract/10.1103/PhysRevA.97.011801|Pulse growth dynamics in laser mode locking]] || A theoretical and numerical analysis of pulse formation in a mode-locked laser.
|-
| Journal Name || [[URL|Title]] || Description.
|-

|}

'''6/21/17:'''
{| class="wikitable sortable"
|-
! Journal Name !! Article Title !! Description
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n5/full/nphoton.2017.58.html Fast silicon photodiodes] || Interesting summary of photodiode technology and limitations. Can response time be increased without sacrificing sensitivity?
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n4/full/nphoton.2017.32.html Spatial beam self-cleaning in multimode fibres] || The Kerr effect caused by high intensity beams can result in more light coupling into the fundamental mode of a multi-mode fiber, causing minimal beam speckling at the output.
|-
| Science || [http://science.sciencemag.org/content/356/6340/837 Quantum sensing with arbitrary frequency resolution] || NV centers in diamond are used to detect the frequency of oscillating magnetic fields with submillihertz resolution.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.223605 Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities] || By coupling light into a cavity with an extremely small mode volume, nonlinear optical effects can be observed with very small numbers of photons.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.243201 Ultrafast Magnetization of a Dense Molecular Gas with an Optical Centrifuge] || A new technique allows for magnetization of much denser gases than was previously possible.
|-
| Journal of Computational Physics || [http://www.sciencedirect.com/science/article/pii/S0021999116306301 Constructing non-reflecting boundary conditions using summation-by-parts in time] || An alternate technique for constructing non-reflecting boundaries, supposedly simpler than current techniques such as perfectly-matched layers (PMLs).
|-
| Nature Communications || [https://www.nature.com/articles/ncomms15610 Harnessing speckle for a sub-femtometer resolved broadband wavemeter and laser stabilization] || They demonstrate speckle-pattern based wavemeter with about 1 MHz frequency resolution
|-
| Nature Communications || [https://www.nature.com/articles/ncomms15849?WT.feed_name=subjects_physical-chemistry Observing electron localization in dissociating H2+ molecule in real time] || They use pump-probe technique with CEP stabilized ~5 fs long pulses to probe dissociation dynamics of H2+ in femtosecond time scales
|-
| Journal of the Optical Society of America A || [https://www.osapublishing.org/abstract.cfm?uri=cleo_qels-2017-FTu3D.2&origin=search Raman-assisted broadband Kerr frequency comb generation in AlN-on-sapphire microresonators] || Four wave mixing is used in a AlN film to build a frequency comb spanning 1.2-2.2 um
|-
| Nature Communications || [https://www.nature.com/articles/ncomms1984 Quantifying the magnetic nature of light emission] || Light emitted from Europium ions is decomposed into parts originating from electric dipole transitions and magnetic dipole transitions
|-
| Optics Express || [https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-25-11-12935&id=367108 Straightforward method to measure optomechanically induced transparency] || Optomechanically induced transparency is demonstrated without the use of a homodyne field
|-
| arxiv || [https://arxiv.org/pdf/1712.00655.pdf Dark state optical lattice with sub-wavelength spatial structure] || Experimental realization of an optical lattice for cold atoms with
sub-wavelength spatial structure

|}

Journal Club

2017-06-21T19:15:08Z

Karpel:

'''6/21/17:'''
{| class="wikitable sortable"
|-
! Journal Name !! Article Title !! Description
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n5/full/nphoton.2017.58.html Fast silicon photodiodes] || Interesting summary of photodiode technology and limitations. Can response time be increased without sacrificing sensitivity?
|-
| Nature Photonics || [http://www.nature.com/nphoton/journal/v11/n4/full/nphoton.2017.32.html Spatial beam self-cleaning in multimode fibres] || The Kerr effect caused by high intensity beams can result in more light coupling into the fundamental mode of a multi-mode fiber, causing minimal beam speckling at the output.
|-
| Science || [http://science.sciencemag.org/content/356/6340/837 Quantum sensing with arbitrary frequency resolution] || NV centers in diamond are used to detect the frequency of oscillating magnetic fields with submillihertz resolution.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.223605 Self-Similar Nanocavity Design with Ultrasmall Mode Volume for Single-Photon Nonlinearities] || By coupling light into a cavity with an extremely small mode volume, nonlinear optical effects can be observed with very small numbers of photons.
|-
| Physical Review Letters || [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.243201 Ultrafast Magnetization of a Dense Molecular Gas with an Optical Centrifuge] || A new technique allows for magnetization of much denser gases than was previously possible.
|-
| Journal of Computational Physics || [http://www.sciencedirect.com/science/article/pii/S0021999116306301 Constructing non-reflecting boundary conditions using summation-by-parts in time] || An alternate technique for constructing non-reflecting boundaries, supposedly simpler than current techniques such as perfectly-matched layers (PMLs).
|-
| Example || Example || Example
|-
| Example || Example || Example
|-
| Example || Example || Example
|-
| Example || Example || Example
|}

Ti:Sapph Laser

2016-07-25T20:39:35Z

Karpel: /* Equipment */

== Equipment ==
Diode data sheet:
[[File:NDB7A75.png]]

Water blocks:
[[File:waterblock.pdf]]

Crystal base:
[[File:9081g.pdf]]

== Cavity Geometry ==

Short arm length = 15 cm

Long arm length = 80 cm

Focusing region = 10.45 cm

Crystal is 5.1 cm from 7.5 cm ROC mirror

Folding angle is 18 deg

Will see if it's possible to move the short arm in and decrease the folding angle (both of these help the astigmatism). Geometric constraints of the mirror mounts prevent the original fully optimized version.

== Alignment Procedure ==

# Set up the HeNe so that it intersects some point at the cavity folding angle (relative to a line of holes on the table). At that point, place the center of the first curved mirror.
# Angle the first curved mirror so that the beam travels straight along the hole line.
# Place an iris along the HeNe path after the second HeNe mirror but before where cavity flat mirror will be set up. Make sure the beam passes through the iris when almost closed.
# Place the crystal so that the beam travels into the crystal at the Brewster angle (this will require a tilt of 30.4 deg relative to the hole line), and therefore exits parallel to the hole line but slightly displaced. Make sure to get the distance from the center of the crystal to the mirror correct!
# Place the center of the second curved mirror at the correct distance away from the crystal, on the displaced-but-still-parallel beam path.
# Angle the second curved mirror so that it propagates away at the cavity folding angle, now on the other side of the hole line.
# Place the output coupler at the desired distance for the long arm. Use the iris from step 2 to make sure it retroreflects the beam precisely.
# Place the flat mirror at the short arm distance from the first curved mirror. Use the iris to align the retroreflection from the back of the mirror.

== Things to Try ==

Remove short arm flat mirror and align blue along hene/780

Mode match 780 and look for interference at the output

File:9081g.pdf

2016-07-25T20:39:20Z

Karpel:

File:Waterblock.pdf

2016-07-25T20:38:36Z

Karpel:

File:NDB7A75.png

2016-07-25T20:36:42Z

Karpel:

Ti:Sapph Laser

2016-07-25T20:36:06Z

Karpel:

== Equipment ==
[[File:NDB7A75.png]]

== Cavity Geometry ==

Short arm length = 15 cm

Long arm length = 80 cm

Focusing region = 10.45 cm

Crystal is 5.1 cm from 7.5 cm ROC mirror

Folding angle is 18 deg

Will see if it's possible to move the short arm in and decrease the folding angle (both of these help the astigmatism). Geometric constraints of the mirror mounts prevent the original fully optimized version.

== Alignment Procedure ==

# Set up the HeNe so that it intersects some point at the cavity folding angle (relative to a line of holes on the table). At that point, place the center of the first curved mirror.
# Angle the first curved mirror so that the beam travels straight along the hole line.
# Place an iris along the HeNe path after the second HeNe mirror but before where cavity flat mirror will be set up. Make sure the beam passes through the iris when almost closed.
# Place the crystal so that the beam travels into the crystal at the Brewster angle (this will require a tilt of 30.4 deg relative to the hole line), and therefore exits parallel to the hole line but slightly displaced. Make sure to get the distance from the center of the crystal to the mirror correct!
# Place the center of the second curved mirror at the correct distance away from the crystal, on the displaced-but-still-parallel beam path.
# Angle the second curved mirror so that it propagates away at the cavity folding angle, now on the other side of the hole line.
# Place the output coupler at the desired distance for the long arm. Use the iris from step 2 to make sure it retroreflects the beam precisely.
# Place the flat mirror at the short arm distance from the first curved mirror. Use the iris to align the retroreflection from the back of the mirror.

== Things to Try ==

Remove short arm flat mirror and align blue along hene/780

Mode match 780 and look for interference at the output

JTK Notebook

2016-07-15T18:29:23Z

Karpel: /* Projects */

== Projects ==

[[Ti:Sapph Laser]] [https://github.com/JoshKarpel/cavities GitHub Link]

[[Ionization]] [https://github.com/JoshKarpel/ionization GitHub Link]

To see the code you'll need to be added as a collaborator. Email me at karpel@wisc.edu or josh.karpel@gmail.com and let me know the email on your GitHub account and I'll add you.

== To Do ==

===== Short Term =====
* Assemble Ti:sapph laser

===== Long Term =====
* Build box for Ti:sapph laser

===== Theory =====
* Work through Raman System Effective Hamiltonian calculations

==== To Buy ====

* Ti:sapph cavity saturable absorber
* Blue optics (cylindrical-lens telescope, focusing lens) (maybe not necessary)
* Optical breadboard

== Log ==

'''2015-9-1'''
* Measured diode current vs power curve. Max is 2.8 W of output power at 3 A input current.
* Drilled a hole in the top of the crystal mount to add a set screw. Slathered the inside of the hole with thermal paste, slipped the crystal in, and tightened the set screw. Crystal is held quite solidly! May still have to redesign at some point, but this will definitely work for now. Some concern over thermal paste on sides of crystal, may want to clean it off at some point.
* Aligned blue beam through crystal. Very cool! Crystal mount holds at 15 deg C easily. Possible concerns over difference between this temperature and the internal temperature of the crystal inside the beam path, but we don't have a way to measure that. Ran for ~1 hour, no visible signs of damage. Not too worried.
* Took a first run at the absorption measurement. 2.8 W in, 1 W made it through the crystal, which is 64% absorption if true - doubtful. We're only measuring transmission, so we can't be sure that the full 2.8 W is incident on the crystal. Probable pre-crystal loss mechanisms: scattering, polarization/Brewster losses (although we seem to have landed very close on our rough alignment).
* Added green dots to diode tube and mount - when the dots are lined up the output is coming out p-polarized relative to the crystal. Note that rotating the diode tube changes the beam path because I'm bad at machining, so it won't be aligned if you rotate it anyway.

'''2015-8-31'''
* Finished water chiller assembly and tested it. Many possible settings give OK performance, but I the best performance is when the water temperature is as low as possible (10 deg C), with the diode mount held at 20 deg C with the full 3 A of current running.

'''2015-8-14'''
* Last water chiller parts should arrive today.
* Working on theory/programming for the most part.

'''2015-8-6'''
* Made TEC wire connector for crystal mount. Everything is ready to be assembled when the water chiller accessories get here. Incidentally: distilled water is on the fourth floor, in the nitrogen room near the undergrad labs. There's a jug under the table in the other side of the lab.
* Apparently Ann did not actually submit the mirror purchase order because my email title was not specific enough for her to look at (wtf...). Issue is resolved, order has been placed.
* Started writing up some notes on Ti:sapph stuff in LaTeX.

'''2015-8-5'''
* Zach Simmons passed his thesis defense. Huzzah!
* Ordered water chiller accessories. Should be here in two days?

'''2015-7-30'''
* Talked to Ann about the missing Thorlabs order and water chiller. Looks like she never processed the requests - issue is now resolved.
* Started working through the theory in Appendix A of Josh's thesis.

'''2015-7-29'''
* Started finalizing Gaussian Beam Tools v4.0 (commenting, examples, etc.)
* Worked with David on wrangling the cavity lock. Maybe works a bit better than before, but still not great (messy output, still no Stokes beam). Did get better output power (100 mW with vacuum, ~60 with .2 atm of D2).

'''2015-7-27'''
* Started digging into SESAMs. Got OK to buy a SESAM (centered on 800 nm), but I sent an email to the diode pumping paper people to see how they sourced their broadband SESAM. They're in England, so it may take a day or two to get a reply.
* Drilled holes for water block on diode mount. Managed to break the tap off in the second hole, rendering it totally unusable. Plan is to screw it down using only one hole. Ugh...
* Talk to Deniz and David about how to tune the Ti:sapph - looks like it's done via an aperture between the second prism and the output coupler. Will need to think about what kind of aperture to use (knife-edge?, must be on translation stage to move back and forth). Tunable is a good first step before mode-locking - proof of concept, make sure we can see the output, etc.

'''2015-7-24'''
* BATOP got back to me - all their products are just stock stuff, apparently, not very open to custom orders. Reflekron's person is on vacation, apparently. Wonderful.

'''2015-7-23'''
* Sent emails to two places that sell SAMs. Don't seem to be many places...
* Worked on Gaussian Beam Tools v4.0.

'''2015-7-22'''
* Did presentation in group meeting.

'''2015-7-21'''
* Pulled the trigger on the mirror order from Lambda.

'''2015-7-20'''
* Worked on Gaussian Beam Tools v4.0.
* Worked on Ti:sapph group meeting presentation.

'''2015-7-16'''
* Talked about final mirror order with Deniz. Decided on 10 mirrors (2 R = 10 cm curved, 2 R = 7.5 cm curved, 4 flat, 99% output coupler, 98% output coupler). Emailed Lambda for another quote request and with a few more questions (not that they've responded to my last email...). Definitely need to know what they mean by "high reflectance" - we want to minimize cavity losses to make the laser more efficient. The diode pumping papers I'm working off quote 0.7% cavity losses (Finesse is around 900).
* Emailed ECI for the revised quote as well. I imagine it will be very expensive.
* Completed NSF RCR training.
* Emailed Reflekron about a SESAM.
* Started writing Gaussian Beam Tools v4.0.

'''2015-7-15'''
* Found a stable Z cavity with a folding angle of 10 degrees, a total length of about a meter, and plenty of stability room to move the FS prisms around in. Will require tuning once it's operating to get the crystal and prisms positioned right. Need a way to do an interferometric measurement of the pulses to analyze the GVD compensation?
* Incidentally, fixed (all of?) the KeyError problems by naively upscaling all the units (so that it's not working with such small floats all the time) and adding the keys to the position list. There's now a small problem where, in a cavity, it's possible that the endpoint of the position list will not be exactly where you wanted it to be, throwing off the symmetry of the calculation. Increasing the unit upscaling seems to help. Also, wrote a neat waist detection algorithm. Now have to rewrite a bunch of older code to use that. Maybe just save it for v4...

'''2015-7-13'''
* Emailed Lambda back with more questions re: mirrors.
* Realized we need to use a Z cavity instead of a bowtie cavity so that we can use a prism pair for GVD (Group Velocity Dispersion) compensation. Started looking at cavity stability and how prism pairs work as GVD compensators.
* Decided I probably need to massage the code a little to avoid running into key errors because of floating points. Will probably recode everything so that it works in tenths of a millimeter as the "base unit" instead of meters, so that everything can be an int. My other thought is to simply add the dictionary keys to the position list - this would effectively decouple the position list resolution from the optical element positions, which would be very nice anyway (it would let you make things like cavity length scans at higher resolution than currently works). Still worried about floating point key errors with that method though. Maybe a combination....

'''2015-7-10'''
* Finished Gaussian Beam Tools v3.2, which reimplements existing cavity stability analysis MatLab code.

'''2015-7-8'''
* Tried to get some mill time today, but all the machines were full. Not urgent, so I'll let it calm down a little.
* Started making slides for talking about the Ti:sapph laser to the group.
* Watched over David's shoulder while he tried to get the cavity lock behaving better.
* Started writing Gaussian Beam Tools v3.2, which will re-implement my existing cavity analysis MatLab code.

'''2015-7-7'''
* Sent out Gaussian Beam Tools v3.1, with fixes for issues running on Mac.

'''2015-7-6'''
* Gaussian Beam Tools v3.0 is done. Sent it out. Nick found that there were some problems with running it on Mac. Will fix issues and send out v3.1 tomorrow.

'''2015-7-2'''
* Wrote some code to back out q values from measured beam parameters. Mode Matching v2 is basically done now - it replicates all of the functionality of David's code and expands it a bit by letting you use it in a "plotting" mode with no mode matching, and by letting you work with any number of lenses.
* Thinking about v3: replace lenses with optical elements as classes, handle the position rail better (maybe a class of it's own?). Basically use classes to generalize and expand what the code can do.

'''2015-7-1'''
* Continued working on Mode Matching v2.
* Heard back from ATF on mirror quote. Order is too small and specialized for them to do...

'''2015-6-30'''
* Wrote v2 of the mode matching program from scratch with some new ideas. Worked great on the first try!

'''2015-6-29'''
* A bit downtime for the next week and a half while the student shop is closed. Decided to write a program to do mode matching. Wrote v1 today, and it was awful and didn't work at all.
* Ordered the copper part of the crystal mount from eMachineShop. ETA ~3 weeks.

'''2015-6-25'''
* Got quote back from ECI - $13000! Way too expensive. Asked them to redo quote without the backs AR-coated to see what that's like. Sent quote request to [http://www.lambda.cc/ Lambda].

'''2015-6-24'''
* REO got back to me and said they don't do mirror quotes for such small orders. Sent a quote request to [http://www.evaporatedcoatings.com/index.php ECI].
* ECI got back to me within 30 minutes with questions. Now that's what I call customer support...
* Made aluminum part of crystal mount.
* Haven't heard back from ATF on mirror quote or eMachineShop on copper part. It's not like it's their job or anything....

'''2015-6-23'''
* Got in early to do some machining but all three mills were already being used...
* Sent passive-aggressive emails following up on the mirror quotes.
* Got a quote on indium foil. Sent in purchase request.
* Started working through Raman system theory.
* Heard back from Advantech Machining. They won't do such a small job.

'''2015-6-22'''
* Ordered TEC, thermistor, and Kapton tape from Thorlabs. Ordered new mount from Newport. Ordered water chiller from eBay. Ordered aluminum from the stock room to make the aluminum part of the crystal mount.
* Asked for a quote on indium foil.
* Asked for quotes on making the copper part of the crystal mount from [http://www.emachineshop.com/ eMachineShop] and [http://www.advantechmachining.com/index.html Advantech Machining].
* No response on any of the mirror quotes except the questions from Layertec. Will send passive-aggressive emails tomorrow.

'''2015-6-18'''
* Realized the whole mounting scheme won't work because the Thorlabs rotation/translation mount is too large. Will rework design tomorrow to use [http://search.newport.com/?x2=sku&q2=9081 this mount] instead. Will likely have to buy more aluminum and copper stock (gdosafjoijforngoasjf). May look into getting the copper part of the mount outsourced - it's going to involve fairly precise machining on a small piece, and the shop will be closed for a week and a half anyway. The aluminum part I'll do next week.

'''2015-6-17'''
* Cut channel into diode laser mount. Waiting to drill screw holes until I get the part to see if I need to mill any more out to make it fit.

'''2015-6-16'''
* Got questions back from Thomas at Layertec. Sent answers. They're working on a quote.

'''2015-6-15'''
* Ordered water blocks from Custom Thermoelectric.
* Ordered rotation/translation mount from Thorlabs.
* Designed channel cut for diode laser water cooling modification. Looks like it should work with no problems...
* Designed crystal mount.
* Ordered crystal mount copper/aluminum stock.

'''2015-6-11'''
* Talked to Deniz about lasing direction. Decided we don't need an intracavity isolator for the Ti:sapph laser. The output coupler will provide enough asymmetry to force lasing in the correct direction.
* Sent email to Layertec requesting quote for Ti:sapph cavity mirrors.
* Talked to Zach about design for Ti:sapph crystal mount. Decided on basic design using water block, possibly from [http://www.customthermoelectric.com/Water_blocks.html Custom Thermoelectric]. Crystal should probably be wrapped in thin indium foil for better contact with copper. Also talked about cutting a "channel" out of the diode laser aluminum block to add a similar water block below the TEC.

JTK Notebook

2016-07-15T18:27:03Z

Karpel: /* Projects */

== Projects ==

[[Ti:Sapph Laser]]
[[Ionization]]

== To Do ==

===== Short Term =====
* Assemble Ti:sapph laser

===== Long Term =====
* Build box for Ti:sapph laser

===== Theory =====
* Work through Raman System Effective Hamiltonian calculations

==== To Buy ====

* Ti:sapph cavity saturable absorber
* Blue optics (cylindrical-lens telescope, focusing lens) (maybe not necessary)
* Optical breadboard

== Log ==

'''2015-9-1'''
* Measured diode current vs power curve. Max is 2.8 W of output power at 3 A input current.
* Drilled a hole in the top of the crystal mount to add a set screw. Slathered the inside of the hole with thermal paste, slipped the crystal in, and tightened the set screw. Crystal is held quite solidly! May still have to redesign at some point, but this will definitely work for now. Some concern over thermal paste on sides of crystal, may want to clean it off at some point.
* Aligned blue beam through crystal. Very cool! Crystal mount holds at 15 deg C easily. Possible concerns over difference between this temperature and the internal temperature of the crystal inside the beam path, but we don't have a way to measure that. Ran for ~1 hour, no visible signs of damage. Not too worried.
* Took a first run at the absorption measurement. 2.8 W in, 1 W made it through the crystal, which is 64% absorption if true - doubtful. We're only measuring transmission, so we can't be sure that the full 2.8 W is incident on the crystal. Probable pre-crystal loss mechanisms: scattering, polarization/Brewster losses (although we seem to have landed very close on our rough alignment).
* Added green dots to diode tube and mount - when the dots are lined up the output is coming out p-polarized relative to the crystal. Note that rotating the diode tube changes the beam path because I'm bad at machining, so it won't be aligned if you rotate it anyway.

'''2015-8-31'''
* Finished water chiller assembly and tested it. Many possible settings give OK performance, but I the best performance is when the water temperature is as low as possible (10 deg C), with the diode mount held at 20 deg C with the full 3 A of current running.

'''2015-8-14'''
* Last water chiller parts should arrive today.
* Working on theory/programming for the most part.

'''2015-8-6'''
* Made TEC wire connector for crystal mount. Everything is ready to be assembled when the water chiller accessories get here. Incidentally: distilled water is on the fourth floor, in the nitrogen room near the undergrad labs. There's a jug under the table in the other side of the lab.
* Apparently Ann did not actually submit the mirror purchase order because my email title was not specific enough for her to look at (wtf...). Issue is resolved, order has been placed.
* Started writing up some notes on Ti:sapph stuff in LaTeX.

'''2015-8-5'''
* Zach Simmons passed his thesis defense. Huzzah!
* Ordered water chiller accessories. Should be here in two days?

'''2015-7-30'''
* Talked to Ann about the missing Thorlabs order and water chiller. Looks like she never processed the requests - issue is now resolved.
* Started working through the theory in Appendix A of Josh's thesis.

'''2015-7-29'''
* Started finalizing Gaussian Beam Tools v4.0 (commenting, examples, etc.)
* Worked with David on wrangling the cavity lock. Maybe works a bit better than before, but still not great (messy output, still no Stokes beam). Did get better output power (100 mW with vacuum, ~60 with .2 atm of D2).

'''2015-7-27'''
* Started digging into SESAMs. Got OK to buy a SESAM (centered on 800 nm), but I sent an email to the diode pumping paper people to see how they sourced their broadband SESAM. They're in England, so it may take a day or two to get a reply.
* Drilled holes for water block on diode mount. Managed to break the tap off in the second hole, rendering it totally unusable. Plan is to screw it down using only one hole. Ugh...
* Talk to Deniz and David about how to tune the Ti:sapph - looks like it's done via an aperture between the second prism and the output coupler. Will need to think about what kind of aperture to use (knife-edge?, must be on translation stage to move back and forth). Tunable is a good first step before mode-locking - proof of concept, make sure we can see the output, etc.

'''2015-7-24'''
* BATOP got back to me - all their products are just stock stuff, apparently, not very open to custom orders. Reflekron's person is on vacation, apparently. Wonderful.

'''2015-7-23'''
* Sent emails to two places that sell SAMs. Don't seem to be many places...
* Worked on Gaussian Beam Tools v4.0.

'''2015-7-22'''
* Did presentation in group meeting.

'''2015-7-21'''
* Pulled the trigger on the mirror order from Lambda.

'''2015-7-20'''
* Worked on Gaussian Beam Tools v4.0.
* Worked on Ti:sapph group meeting presentation.

'''2015-7-16'''
* Talked about final mirror order with Deniz. Decided on 10 mirrors (2 R = 10 cm curved, 2 R = 7.5 cm curved, 4 flat, 99% output coupler, 98% output coupler). Emailed Lambda for another quote request and with a few more questions (not that they've responded to my last email...). Definitely need to know what they mean by "high reflectance" - we want to minimize cavity losses to make the laser more efficient. The diode pumping papers I'm working off quote 0.7% cavity losses (Finesse is around 900).
* Emailed ECI for the revised quote as well. I imagine it will be very expensive.
* Completed NSF RCR training.
* Emailed Reflekron about a SESAM.
* Started writing Gaussian Beam Tools v4.0.

'''2015-7-15'''
* Found a stable Z cavity with a folding angle of 10 degrees, a total length of about a meter, and plenty of stability room to move the FS prisms around in. Will require tuning once it's operating to get the crystal and prisms positioned right. Need a way to do an interferometric measurement of the pulses to analyze the GVD compensation?
* Incidentally, fixed (all of?) the KeyError problems by naively upscaling all the units (so that it's not working with such small floats all the time) and adding the keys to the position list. There's now a small problem where, in a cavity, it's possible that the endpoint of the position list will not be exactly where you wanted it to be, throwing off the symmetry of the calculation. Increasing the unit upscaling seems to help. Also, wrote a neat waist detection algorithm. Now have to rewrite a bunch of older code to use that. Maybe just save it for v4...

'''2015-7-13'''
* Emailed Lambda back with more questions re: mirrors.
* Realized we need to use a Z cavity instead of a bowtie cavity so that we can use a prism pair for GVD (Group Velocity Dispersion) compensation. Started looking at cavity stability and how prism pairs work as GVD compensators.
* Decided I probably need to massage the code a little to avoid running into key errors because of floating points. Will probably recode everything so that it works in tenths of a millimeter as the "base unit" instead of meters, so that everything can be an int. My other thought is to simply add the dictionary keys to the position list - this would effectively decouple the position list resolution from the optical element positions, which would be very nice anyway (it would let you make things like cavity length scans at higher resolution than currently works). Still worried about floating point key errors with that method though. Maybe a combination....

'''2015-7-10'''
* Finished Gaussian Beam Tools v3.2, which reimplements existing cavity stability analysis MatLab code.

'''2015-7-8'''
* Tried to get some mill time today, but all the machines were full. Not urgent, so I'll let it calm down a little.
* Started making slides for talking about the Ti:sapph laser to the group.
* Watched over David's shoulder while he tried to get the cavity lock behaving better.
* Started writing Gaussian Beam Tools v3.2, which will re-implement my existing cavity analysis MatLab code.

'''2015-7-7'''
* Sent out Gaussian Beam Tools v3.1, with fixes for issues running on Mac.

'''2015-7-6'''
* Gaussian Beam Tools v3.0 is done. Sent it out. Nick found that there were some problems with running it on Mac. Will fix issues and send out v3.1 tomorrow.

'''2015-7-2'''
* Wrote some code to back out q values from measured beam parameters. Mode Matching v2 is basically done now - it replicates all of the functionality of David's code and expands it a bit by letting you use it in a "plotting" mode with no mode matching, and by letting you work with any number of lenses.
* Thinking about v3: replace lenses with optical elements as classes, handle the position rail better (maybe a class of it's own?). Basically use classes to generalize and expand what the code can do.

'''2015-7-1'''
* Continued working on Mode Matching v2.
* Heard back from ATF on mirror quote. Order is too small and specialized for them to do...

'''2015-6-30'''
* Wrote v2 of the mode matching program from scratch with some new ideas. Worked great on the first try!

'''2015-6-29'''
* A bit downtime for the next week and a half while the student shop is closed. Decided to write a program to do mode matching. Wrote v1 today, and it was awful and didn't work at all.
* Ordered the copper part of the crystal mount from eMachineShop. ETA ~3 weeks.

'''2015-6-25'''
* Got quote back from ECI - $13000! Way too expensive. Asked them to redo quote without the backs AR-coated to see what that's like. Sent quote request to [http://www.lambda.cc/ Lambda].

'''2015-6-24'''
* REO got back to me and said they don't do mirror quotes for such small orders. Sent a quote request to [http://www.evaporatedcoatings.com/index.php ECI].
* ECI got back to me within 30 minutes with questions. Now that's what I call customer support...
* Made aluminum part of crystal mount.
* Haven't heard back from ATF on mirror quote or eMachineShop on copper part. It's not like it's their job or anything....

'''2015-6-23'''
* Got in early to do some machining but all three mills were already being used...
* Sent passive-aggressive emails following up on the mirror quotes.
* Got a quote on indium foil. Sent in purchase request.
* Started working through Raman system theory.
* Heard back from Advantech Machining. They won't do such a small job.

'''2015-6-22'''
* Ordered TEC, thermistor, and Kapton tape from Thorlabs. Ordered new mount from Newport. Ordered water chiller from eBay. Ordered aluminum from the stock room to make the aluminum part of the crystal mount.
* Asked for a quote on indium foil.
* Asked for quotes on making the copper part of the crystal mount from [http://www.emachineshop.com/ eMachineShop] and [http://www.advantechmachining.com/index.html Advantech Machining].
* No response on any of the mirror quotes except the questions from Layertec. Will send passive-aggressive emails tomorrow.

'''2015-6-18'''
* Realized the whole mounting scheme won't work because the Thorlabs rotation/translation mount is too large. Will rework design tomorrow to use [http://search.newport.com/?x2=sku&q2=9081 this mount] instead. Will likely have to buy more aluminum and copper stock (gdosafjoijforngoasjf). May look into getting the copper part of the mount outsourced - it's going to involve fairly precise machining on a small piece, and the shop will be closed for a week and a half anyway. The aluminum part I'll do next week.

'''2015-6-17'''
* Cut channel into diode laser mount. Waiting to drill screw holes until I get the part to see if I need to mill any more out to make it fit.

'''2015-6-16'''
* Got questions back from Thomas at Layertec. Sent answers. They're working on a quote.

'''2015-6-15'''
* Ordered water blocks from Custom Thermoelectric.
* Ordered rotation/translation mount from Thorlabs.
* Designed channel cut for diode laser water cooling modification. Looks like it should work with no problems...
* Designed crystal mount.
* Ordered crystal mount copper/aluminum stock.

'''2015-6-11'''
* Talked to Deniz about lasing direction. Decided we don't need an intracavity isolator for the Ti:sapph laser. The output coupler will provide enough asymmetry to force lasing in the correct direction.
* Sent email to Layertec requesting quote for Ti:sapph cavity mirrors.
* Talked to Zach about design for Ti:sapph crystal mount. Decided on basic design using water block, possibly from [http://www.customthermoelectric.com/Water_blocks.html Custom Thermoelectric]. Crystal should probably be wrapped in thin indium foil for better contact with copper. Also talked about cutting a "channel" out of the diode laser aluminum block to add a similar water block below the TEC.

Ti:Sapph Laser

2015-09-11T14:45:06Z

Karpel:

== Cavity Geometry ==

Short arm length = 15 cm

Long arm length = 80 cm

Focusing region = 10.45 cm

Crystal is 5.1 cm from 7.5 cm ROC mirror

Folding angle is 18 deg

Will see if it's possible to move the short arm in and decrease the folding angle (both of these help the astigmatism). Geometric constraints of the mirror mounts prevent the original fully optimized version.

== Alignment Procedure ==

# Set up the HeNe so that it intersects some point at the cavity folding angle (relative to a line of holes on the table). At that point, place the center of the first curved mirror.
# Angle the first curved mirror so that the beam travels straight along the hole line.
# Place an iris along the HeNe path after the second HeNe mirror but before where cavity flat mirror will be set up. Make sure the beam passes through the iris when almost closed.
# Place the crystal so that the beam travels into the crystal at the Brewster angle (this will require a tilt of 30.4 deg relative to the hole line), and therefore exits parallel to the hole line but slightly displaced. Make sure to get the distance from the center of the crystal to the mirror correct!
# Place the center of the second curved mirror at the correct distance away from the crystal, on the displaced-but-still-parallel beam path.
# Angle the second curved mirror so that it propagates away at the cavity folding angle, now on the other side of the hole line.
# Place the output coupler at the desired distance for the long arm. Use the iris from step 2 to make sure it retroreflects the beam precisely.
# Place the flat mirror at the short arm distance from the first curved mirror. Use the iris to align the retroreflection from the back of the mirror.

== Things to Try ==

Remove short arm flat mirror and align blue along hene/780

Mode match 780 and look for interference at the output

2015-07-08T22:09:32Z

Karpel:

JTK Notebook

2015-07-02T17:20:50Z

Karpel:

JTK Notebook

2015-06-25T16:56:09Z

Karpel:

== To Do ==

===== Short Term =====
* Modify diode mount for water cooling (almost done, will drill screw holes once water blocks get here)
* Build crystal mount

===== Long Term =====
* Assemble Ti:sapph laser
* Build box for Ti:sapph laser

===== Theory =====
* Work through Raman System Effective Hamiltonian calculations

==== To Buy ====

* Water chiller accessories (tubing, etc.)
* Ti:sapph cavity mirrors (probably from Layertec)
* Ti:sapph cavity saturable absorber
* Ti:sapph extracavity optics
* Blue optics (cylindrical-lens telescope, focusing lens)

== Log ==

'''6/25/2015'''
* Got quote back from ECI - $13000! Way too expensive. Asked them to redo quote without the backs AR-coated to see what that's like. Sent quote request to [http://www.lambda.cc/ Lambda].
* Ordered the copper part of the crystal mount from eMachineShop.

'''6/24/2015'''
* REO got back to me and said they don't do mirror quotes for such small orders. Sent a quote request to [http://www.evaporatedcoatings.com/index.php ECI].
* ECI got back to me within 30 minutes with questions. Now that's what I call customer support...
* Made aluminum part of crystal mount.
* Haven't heard back from ATF on mirror quote or eMachineShop on copper part. It's not like it's their job or anything....

'''6/23/2015'''
* Got in early to do some machining but all three mills were already being used...
* Sent passive-aggressive emails following up on the mirror quotes.
* Got a quote on indium foil. Sent in purchase request.
* Started working through Raman system theory.
* Heard back from Advantech Machining. They won't do such a small job.

'''6/22/2015'''
* Ordered TEC, thermistor, and Kapton tape from Thorlabs. Ordered new mount from Newport. Ordered water chiller from eBay. Ordered aluminum from the stock room to make the aluminum part of the crystal mount.
* Asked for a quote on indium foil.
* Asked for quotes on making the copper part of the crystal mount from [http://www.emachineshop.com/ eMachineShop] and [http://www.advantechmachining.com/index.html Advantech Machining].
* No response on any of the mirror quotes except the questions from Layertec. Will send passive-aggressive emails tomorrow.

'''6/18/2015'''
* Realized the whole mounting scheme won't work because the Thorlabs rotation/translation mount is too large. Will rework design tomorrow to use [http://search.newport.com/?x2=sku&q2=9081 this mount] instead. Will likely have to buy more aluminum and copper stock (gdosafjoijforngoasjf). May look into getting the copper part of the mount outsourced - it's going to involve fairly precise machining on a small piece, and the shop will be closed for a week and a half anyway. The aluminum part I'll do next week.

'''6/17/2015'''
* Cut channel into diode laser mount. Waiting to drill screw holes until I get the part to see if I need to mill any more out to make it fit.

'''6/16/2015'''
* Got questions back from Thomas at Layertec. Sent answers. They're working on a quote.

'''6/15/2015'''
* Ordered water blocks from Custom Thermoelectric.
* Ordered rotation/translation mount from Thorlabs.
* Designed channel cut for diode laser water cooling modification. Looks like it should work with no problems...
* Designed crystal mount.
* Ordered crystal mount copper/aluminum stock.

'''6/11/2015'''
* Talked to Deniz about lasing direction. Decided we don't need an intracavity isolator for the Ti:sapph laser. The output coupler will provide enough asymmetry to force lasing in the correct direction.
* Sent email to Layertec requesting quote for Ti:sapph cavity mirrors.
* Talked to Zach about design for Ti:sapph crystal mount. Decided on basic design using water block, possibly from [http://www.customthermoelectric.com/Water_blocks.html Custom Thermoelectric]. Crystal should probably be wrapped in thin indium foil for better contact with copper. Also talked about cutting a "channel" out of the diode laser aluminum block to add a similar water block below the TEC.

JTK Notebook

2015-06-24T18:17:25Z

Karpel:

== To Do ==

===== Short Term =====
* Modify diode mount for water cooling (almost done, will drill screw holes once water blocks get here)
* Build crystal mount

===== Long Term =====
* Assemble Ti:sapph laser
* Build box for Ti:sapph laser

===== Theory =====
* Work through Raman System Effective Hamiltonian calculations

==== To Buy ====

* Water chiller accessories (tubing, etc.)
* Ti:sapph cavity mirrors (probably from Layertec)
* Ti:sapph cavity saturable absorber
* Ti:sapph extracavity optics
* Blue optics (cylindrical-lens telescope, focusing lens)

== Log ==

'''6/24/2015'''
* REO got back to me and said they don't do mirror quotes for such small orders. Sent a quote request to [http://www.evaporatedcoatings.com/index.php ECI].
* ECI got back to me within 30 minutes with questions. Now that's what I call customer support...
* Made aluminum part of crystal mount.
* Haven't heard back from ATF on mirror quote or eMachineShop on copper part. It's not like it's their job or anything....

'''6/23/2015'''
* Got in early to do some machining but all three mills were already being used...
* Sent passive-aggressive emails following up on the mirror quotes.
* Got a quote on indium foil. Sent in purchase request.
* Started working through Raman system theory.
* Heard back from Advantech Machining. They won't do such a small job.

'''6/22/2015'''
* Ordered TEC, thermistor, and Kapton tape from Thorlabs. Ordered new mount from Newport. Ordered water chiller from eBay. Ordered aluminum from the stock room to make the aluminum part of the crystal mount.
* Asked for a quote on indium foil.
* Asked for quotes on making the copper part of the crystal mount from [http://www.emachineshop.com/ eMachineShop] and [http://www.advantechmachining.com/index.html Advantech Machining].
* No response on any of the mirror quotes except the questions from Layertec. Will send passive-aggressive emails tomorrow.

'''6/18/2015'''
* Realized the whole mounting scheme won't work because the Thorlabs rotation/translation mount is too large. Will rework design tomorrow to use [http://search.newport.com/?x2=sku&q2=9081 this mount] instead. Will likely have to buy more aluminum and copper stock (gdosafjoijforngoasjf). May look into getting the copper part of the mount outsourced - it's going to involve fairly precise machining on a small piece, and the shop will be closed for a week and a half anyway. The aluminum part I'll do next week.

'''6/17/2015'''
* Cut channel into diode laser mount. Waiting to drill screw holes until I get the part to see if I need to mill any more out to make it fit.

'''6/16/2015'''
* Got questions back from Thomas at Layertec. Sent answers. They're working on a quote.

'''6/15/2015'''
* Ordered water blocks from Custom Thermoelectric.
* Ordered rotation/translation mount from Thorlabs.
* Designed channel cut for diode laser water cooling modification. Looks like it should work with no problems...
* Designed crystal mount.
* Ordered crystal mount copper/aluminum stock.

'''6/11/2015'''
* Talked to Deniz about lasing direction. Decided we don't need an intracavity isolator for the Ti:sapph laser. The output coupler will provide enough asymmetry to force lasing in the correct direction.
* Sent email to Layertec requesting quote for Ti:sapph cavity mirrors.
* Talked to Zach about design for Ti:sapph crystal mount. Decided on basic design using water block, possibly from [http://www.customthermoelectric.com/Water_blocks.html Custom Thermoelectric]. Crystal should probably be wrapped in thin indium foil for better contact with copper. Also talked about cutting a "channel" out of the diode laser aluminum block to add a similar water block below the TEC.