Search found 401 matches
- Tue Feb 07, 2023 1:07 pm
- Forum: General Holography
- Topic: Holographic testing of CMB radiation telescopes
- Replies: 0
- Views: 20993
Holographic testing of CMB radiation telescopes
CMB (Cosmic Microwave Background) radiation is radiation in the ~1.9mm region, ie in the microwave region, that pervades space.It's the result of the Big Bang origin of the universe, and detecting it is important to validate and improve the Big Bang Theory. But, the extreme cold of space means that ...
- Mon Jan 23, 2023 12:10 pm
- Forum: General Holography
- Topic: A blue pigment for Sapphire 488
- Replies: 2
- Views: 6718
Re: A blue pigment for Sapphire 488
Here is a hologram made by painting on the model. We shot this about 2015. Joy's procedure for testing appropriate paints was to illuminate each colour paint by all three lasers. Using a red paint as an example for red information from the model: 1. Choose a set of red paints and paint a white card ...
- Thu Jan 19, 2023 1:12 pm
- Forum: Off Topic
- Topic: Holograms in Los Angeles MOCA
- Replies: 0
- Views: 23547
- Sat Jan 07, 2023 9:50 am
- Forum: General Holography
- Topic: Purchasing Lasers
- Replies: 5
- Views: 7494
Re: Purchasing Lasers
Ont thing I forgot to mention is that you need a lens before the screen to expand the combined beam so as to enlarge the interference pattern. The unexpanded beam is too small to see any structure.
- Fri Jan 06, 2023 10:07 am
- Forum: General Holography
- Topic: Purchasing Lasers
- Replies: 5
- Views: 7494
Re: Purchasing Lasers
That leads to another related question: Is there an easy way to measure coherence length of a laser? Thanks again. Yes. You set up a Michelson interferometer, and vary the path difference. I've drawn up a diagram. The beams splitter sends the beam along both path a and path b (black lines). On refl...
- Wed Jan 04, 2023 3:04 pm
- Forum: General Holography
- Topic: Purchasing Lasers
- Replies: 5
- Views: 7494
Re: Purchasing Lasers
You may be interested in a white paper I wrote for Melles Griot
- Fri Dec 16, 2022 11:48 am
- Forum: AgX
- Topic: Printout revisited
- Replies: 3
- Views: 25539
Re: Printout revisited
The solubility of potassium iodide in ethyl alcohol decreases as the concentration of ethyl alcohol increases*. Since the way the iodide reduces printout is by replacement of the bromide ion in emulsions with the iodide ion, the large number of bromide ions still in the emulsion (depending, of cours...
- Tue Dec 13, 2022 4:27 pm
- Forum: Off Topic
- Topic: 3D Zero Order Imaging
- Replies: 0
- Views: 21351
- Mon Oct 17, 2022 9:10 am
- Forum: General Holography
- Topic: Question about speckle reduction
- Replies: 2
- Views: 6554
Re: Question about speckle reduction
Do inhomogeneities in the glass or acrylic cause this? Basically, yes. Speckle is caused by phase differences due to index and thickness differences of components along the optical path, and the rms (root mean square) height of the surface. Because of the extreme coherence of laser light, if the rm...
- Fri Sep 23, 2022 8:53 am
- Forum: Optics
- Topic: Color proximity copies ?
- Replies: 2
- Views: 10425
Re: Color proximity copies ?
Yes. This is a full colour H2 from a full colour, single H1 (not 3 separate H1's) we shot about 7 years ago. The subject matter is the holographic joke referring to the Utah Teapot. The first test of a computer graphic, 3D algorithm used a teapot as a test. The Utah teapot is considered the "He...