Search found 405 matches

by Din
Fri Nov 27, 2015 2:11 pm
Forum: Beginning Holography
Topic: It's time...guidance apppreciated.
Replies: 6
Views: 4643

Re: It's time...guidance apppreciated.

When I saw the kits where the plate rests against the object, I was highly skeptical. Is it really that simple now!?? Will the quality be good? You seem to be talking about the Liti kit. I've heard mixed reports. Some here on the forum seem to have got good results, while I never did. The basic iss...
by Din
Tue Nov 24, 2015 9:54 am
Forum: General Holography
Topic: the word "hologram"
Replies: 8
Views: 4333

Re: the word "hologram"

Petr, a telephone was a method of voice communication alone. You used a telephone (Greek: "distant hearing") to speak to someone and, initially, you got connected via a switchboard. Later, you had a unique numerical code ("phone number"). But, the point is that a telephone allowe...
by Din
Mon Nov 23, 2015 1:30 pm
Forum: General Holography
Topic: the word "hologram"
Replies: 8
Views: 4333

Re: the word "hologram"

Petr, I recall we tried to find a definition of holography that would include all the techniques that uses traditional holograhy (e-beam etc) and exclude all other imaging, reconstructing and recording systems, but we found it impossible. But, the thing I find amusing is that everyone calls it a &qu...
by Din
Sat Nov 21, 2015 5:15 pm
Forum: General Holography
Topic: the word "hologram"
Replies: 8
Views: 4333

Re: the word "hologram"

As an English major in school, we were taught that language is constantly changing, and that as usage of a word changes, the meaning of the word changes. Whether right or wrong, the popular use of a word determines its meaning. Joe, I've been saying this for a number of years now. But, the holograp...
by Din
Tue Nov 03, 2015 1:53 pm
Forum: General Holography
Topic: Edge Lit
Replies: 5
Views: 3679

Re: Edge Lit

John,
This is the best we've got. The biggest challenge is to launch the light through the edge. If you use commercial silver halide, you need to back it with a glass slab and launch into the slab because the plate is fairly thin.
edge-lit1.jpg
edge-lit1.jpg (49.49 KiB) Viewed 3672 times
by Din
Thu Oct 15, 2015 12:32 pm
Forum: DCG
Topic: question about color changes
Replies: 2
Views: 2406

Re: question about color changes

It depends on whether you're shooting H1/H2 or single beam Denisyuks. Even so, there may be many reasons for this colour change Generally, the colour of a reflection hologram is based on the plane separation, angle of recon wrt the reference angle and recon wavelength. There's a formula in Kogelnik ...
by Din
Fri Oct 02, 2015 12:22 pm
Forum: Gallery
Topic: Wedding present
Replies: 2
Views: 6866

Re: Wedding present

Thanks.
by Din
Thu Oct 01, 2015 2:10 pm
Forum: Gallery
Topic: Wedding present
Replies: 2
Views: 6866

Wedding present

Don't do display anymore, but occasionally, I get to play. These are for a wedding present for a friend. They'll have little rubber feet and end up as coasters.
Motorcycles.jpg
Motorcycles.jpg (90.04 KiB) Viewed 6866 times
by Din
Tue Sep 15, 2015 12:48 pm
Forum: General Holography
Topic: making a hologram printer?
Replies: 6
Views: 4530

Re: making a hologram printer?

Gezzer, Yes, that would be a CGH. However, you haven't specified a "reference beam" into the calculation. In this case, you have a "reference beam", that's pretty much on-axis. That is, the reference beam angle is simulated at zero degrees. You need to add the reference beam to g...
by Din
Mon Sep 14, 2015 6:30 pm
Forum: General Holography
Topic: making a hologram printer?
Replies: 6
Views: 4530

Re: making a hologram printer?

For CGH, or Computer Generated Hologram, you actually calculate Fourier terms. Since the far field pattern of any scene is the Fraunhofer diffraction pattern (Note to Petr: Yes, I know you can have Fresnel hologram also! :) ), the fringe pattern recorded on a hologram is the Fraunhogfer diffraction ...