Search found 5 matches

by nobo
Fri Jan 01, 2016 10:25 pm
Forum: Optics
Topic: Rotating Polarization with Mirrors
Replies: 37
Views: 72993

Re: Rotating Polarization with Mirrors

Kate is right. It is the exact equivalent of the image John was referring to. Attached is better diagram. Wish I had SketchUp in the old days. ;-) For your info, the original diagram (pre personal computers) was programmed in Fortran, submitted to microfilm (35mm BW film), then printed on photo pap...
by nobo
Fri Jan 01, 2016 9:23 pm
Forum: General Holography
Topic: why there are some Black stripes on the hologram
Replies: 6
Views: 3449

Re: why there are some Black stripes on the hologram

Most laser diodes are prone to mode-hopping (or slight changes in wavelength) during a holographic exposure, but the effect is unpredictable. I always recommend helium-neon lasers for this reason. They are available at reasonable cost, on eBay for example. The way to be certain that those stripes a...
by nobo
Fri Jan 01, 2016 11:50 am
Forum: General Holography
Topic: why there are some Black stripes on the hologram
Replies: 6
Views: 3449

Re: why there are some Black stripes on the hologram

Black stripes in a hologram are often caused by a mode-hopping laser diode. These are also called "contour fringes" and cover the image of the object in regularly-spaced bright and dark contour stripes, making the object look like a zebra. Besides the parameter of the laser is MRL-III-671...
by nobo
Fri Jan 01, 2016 11:25 am
Forum: General Holography
Topic: why there are some Black stripes on the hologram
Replies: 6
Views: 3449

Re: why there are some Black stripes on the hologram

Black stripes in a hologram are often caused by a mode-hopping laser diode. These are also called "contour fringes" and cover the image of the object in regularly-spaced bright and dark contour stripes, making the object look like a zebra. Thanks for your answering! I know little about th...
by nobo
Fri Jan 01, 2016 10:25 am
Forum: General Holography
Topic: why there are some Black stripes on the hologram
Replies: 6
Views: 3449

why there are some Black stripes on the hologram

I am really interested in hologram and I did some experiences in laboratory. However, I don't know why there are some Black stripes which seems somewhat regular on my hologram. I tried many times but the black stripes still exist and i really hope anyone could help me figure it out. Thank you very m...