David Notebook: Difference between revisions

We also doubled the power of the 780 as measured directly after the TA (see [[David_Notebook#780_Laser_Notes|780 laser notes]]). We still couldn't see a signal on the OSA though, even with lots of averaging and with the beam locked. Looking at the coupling fiber when ramping the cavity, however, we could clearly see the 633 beam flashing above a constant background of 780. Putting in an 780 notch filter and a 633ish bandpass filter (borrowed from 1st floor John), we now have what seems to be a flashing 633 signal with very good contrast (i.e. against very little background). The fact that this filter works makes it even more definitive that what we're looking at is 633. We hope that this will be easier to optimize and finally detect with the OSA. It's confusing that the 633 signal is so visible even through the fiber and when not looking directly at it--is the eye that sensitive to 633, or could we be having equipment issues?