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David Notebook: Difference between revisions
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<strike>I'm getting about 50% transmission from the prism (measuring total power of both beams before prism and just after before they've significantly diverged). I don't know why this is so different from the cited figure, but it's consistent and I'll use it. Using the bandpass filter before the prism I get 11 mW of 1555. So 16.9 mW after filter losses. I'm getting 12 mW of 1555 after the prism though, which would mean 24 mW leaving the cavity. I'm not sure why there's this discrepancy. </strike>
I measured the transmission of the prism directly using the 1064 and 1555 diodes. I found 100% for 1064 and 89% for 1555. After the prism, I measured 20 mW of 1555 and 7 mW of 1064. I didn't use the bandpass filter since I would need to use the prism for the 1064 measurement anyway. Accounting for the prism, that gives 22.5 mW of 1555 and 7 mw of 1064 and 592 W and 219 W just inside the cavity. With the cavity mirror transmittances and beam sizes from yesterday, that gives cavity intensities of:
<math> 26.1 </math> <math> kW/cm^2 </math> and <math> 9.6 </math> <math> kW/cm^2 </math>
'''8/5/14'''
Deniz can calculate the maximum theoretical conversion efficiency of 780 if we know the amount of 1064 and 1555 in the cavity. <strike> I separated the beams with a prism and measured 5 mW maximum of 1064 when locking and 14 mW maximum of 1555. The prism (Thorlabs PS853) has a listed transmittance of ~28% for both 1064 and 1555, so exiting the cavity there should be 17.9 mW of 1064 and 50 mW of 1555. </strike>
The cavity mirror transmits 32 ppm and 38 ppm of 1064 and 1555 respectively, so that puts the powers at 559 W and 1316 W inside the cavity. The beam sizes were both about 1700 μm 30 cm from the cavity, <strike> so the 1064 and 1555 intensities are approximately:
<math> 770 </math> <math> MW/cm^2 </math> and <math> 1810 </math> <math> MW/cm^2 </math> <strike>
I'm skeptical of the prism transmission figure, since I haven't observed losses like that. I'll check directly tomorrow when the cavity is aligned. The bandpass filter lets through ~65% 1555 and blocks almost all 1064.
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