R&D (General)
YuefanGuo - 18:57, Thursday 23 February 2017 (388)
Check the power (part of)
After the ATC people return the table leg back, I found out I need to the alignment again. But after I finished it, tried to get some data of the infrared power. I found out the table was not put back in a good position, when I pushed on one corner, the other side will lift. So Manueal helped me to fixed the table more, and of course I need to adjust the alignment once again after it. I forgot to check the table is horizontal or not, I will do it tomorrow.

So until now I only checked power of half beam path. But it does not seems very reasonable, so I will reduce the power and do it again to check.

I checked the polarization, we are using the S polarization in infrared and get P polarization in green. The dichoric mirror we are using now is HBSY21 from Thorlab, which has a better performance in S polarization in reflection and better in P in transmission. Below is the website for more information:

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=7035&pn=HBSY21

The green power now is about 46mW which measured after the dichoric mirror, and since I cannot put a power meter in the beam path, so I tried to measure the green beam which is reflected by the back surface of the dichoric mirror, and it is separated from the input beam,so I could measure it without block the infrared. And the power of this beam is aobut 4mW. But I need to check about other information of the back surface of the mirror.