Search found 48 matches

by Brian
Fri Apr 12, 2019 6:15 pm
Forum: Gallery
Topic: opal
Replies: 4
Views: 9025

Re: opal

So here I display a photograph of a reflection hologram of the Australian black opal with strong red play-of-color. The hologram is illuminated by a white LED light almost exactly as the opal itself was. So... seems like no big deal, a reflection hologram made using a red laser. But take a closer lo...
by Brian
Fri Apr 12, 2019 6:02 pm
Forum: Gallery
Topic: opal
Replies: 4
Views: 9025

opal

In this post I display a photograph of an Australian black opal with strong red play-of-color sitting on a black acrylic plate. The elliptical opal is about 1 cm along its major axis. In the photograph, the opal is illuminated by a white light LED from below, tilted toward the opal at an angle of ab...
by Brian
Thu Jul 19, 2018 6:21 pm
Forum: Beginning Holography
Topic: Fundamentals of Photonics Volume 1
Replies: 28
Views: 10985

Re: Fundamentals of Photonics Volume 1

Units help :) Agreed. ... you can get some basics even from Goodman's Introduction to Fourier Optics, chapter on Holography. Optical Holography by Collier et al. is OK as well. Practical Volume Holography by Syms is also worth checking. Thank you for the recommendations. I will look into them.
by Brian
Thu Jul 19, 2018 4:14 pm
Forum: Beginning Holography
Topic: Fundamentals of Photonics Volume 1
Replies: 28
Views: 10985

Re: Fundamentals of Photonics Volume 1

By the way, Brian, is this one of your "One question every week"? :) Very true that I haven't been on the forum in quite some time. So catching up, the energy conservation teaser caught my eye, as I have posited it to my students. But all the while I have been making small reflection holograms. Squ...
by Brian
Wed Jul 18, 2018 3:50 pm
Forum: Beginning Holography
Topic: Fundamentals of Photonics Volume 1
Replies: 28
Views: 10985

Re: Fundamentals of Photonics Volume 1

"In the areas where the light waves from S are in phase with those from S1¢, the total amplitude is doubled." But, the intensity, which is what's being recorded, is quadrupled, assuming equal intensities: I(t) = I(1) + I(2) + 2√[(I(1)I(2)]cos(φ) If I(1) = I(2) = I, and φ = 2nπ, then I(t) = 2I + 2I ...
by Brian
Thu Jan 05, 2017 6:23 pm
Forum: General Holography
Topic: Taming the divergence of a 315M
Replies: 5
Views: 2292

Re: Taming the divergence of a 315M

Din wrote: As for contour integration: Why is the contour integral around Western Europe zero? Because all the poles are in Eastern Europe. Ba-Da-Boom!
Haha, who knew contour integration could be time dependent?
by Brian
Fri Dec 16, 2016 11:27 pm
Forum: General Holography
Topic: Taming the divergence of a 315M
Replies: 5
Views: 2292

Re: Taming the divergence of a 315M

I really, really wish I could gave differentiated something or integrated something! Oh! I guess I haven't tried to impress anyone, much less me, I think series expansions and basis set expansions are much more impressive. I have a lot more trouble getting my students to perform binomial expansions...
by Brian
Fri Dec 16, 2016 11:12 pm
Forum: Beginning Holography
Topic: diffraction gratings
Replies: 12
Views: 4519

Re: diffraction gratings

Ed, I'm pretty sure the spectral lamp is krypton. Like 99% sure. The only thing preventing me from being 100% sure is that no sane person would use krypton for a discrete line demonstration. After making a few, we gave up on the large divergence gratings. Setting the plate so far from the divergence...
by Brian
Tue Nov 29, 2016 11:49 am
Forum: Beginning Holography
Topic: diffraction gratings
Replies: 12
Views: 4519

Re: diffraction gratings

Thanks Dinesh! We found the first attempt had ~1400 lines/mm. Lots to explore and improve with this setup, so we'll continue with it for the rest of the semester.
by Brian
Fri Nov 18, 2016 10:06 am
Forum: Beginning Holography
Topic: diffraction gratings
Replies: 12
Views: 4519

Re: diffraction gratings

Just for fun, a picture of the setup before we put down the black cloth. Objective-pinhole seen in the foreground. At the far right is reflected light from the mirror, showing the shadow outline of the plate.
transmission setup a.jpg
transmission setup a.jpg (40.83 KiB) Viewed 2835 times