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ArcticMyst Security by Avery

Lenses for holography?

Joined
Sep 20, 2013
Messages
17,252
Points
113
I would not use a PBS cube with mirrors attached to it. You want the mirrors to be out several inches away for the beam splitter and one should be able to be moved. The distance it can be moved away from and towards the beam splitter will tell you the coherence length of your laser. Where the fringe lines appear and where they disappear is directly related to the coherence length of your laser. You need to be able to measure this distance.
 





Anthony P

Well-known member
Joined
Oct 7, 2018
Messages
529
Points
63
I would not use a PBS cube with mirrors attached to it. You want the mirrors to be out several inches away for the beam splitter and one should be able to be moved. The distance it can be moved away from and towards the beam splitter will tell you the coherence length of your laser. Where the fringe lines appear and where they disappear is directly related to the coherence length of your laser. You need to be able to measure this distance.
Can and will do. Do you have any thoughts on using a polarizer and 1/4 wave retarder to prevent reflected laser beam from re-entering laser? Is there a better way? Seems like the more research I do, the more questions I find. I am all for experimentation, but I also have a budget. I will spend money IFF I know it is going to work. Along those lines, who actually shops at Edmund Optics. Surely even a NASA scientist has heard of e-bay.
 
Joined
Sep 20, 2013
Messages
17,252
Points
113
As long as you don't have your beam splitter right next to the laser, you have nothing to worry about. Have your PBS cube about 12 inches away from your laser and you won't need to worry about back reflections. Be able to move your mirror at least as far as you want the depth of your hologram to be. Measure where the fringes first appear and then where they disappear. This distance times two is your coherence length, IIRC.
 




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