Physics of Holography lecture by Pete Rogina

[@jonathanlangton3097]

Ooooh! Now I get it! Great explanation. I understood all the physics before, but the "non-obvious way it comes together" always eluded me in other explanations. Nice work, Pete!

[@DC-hd9lu]

Best teacher EVER!☆. Even with my asd, learning was so easy and fun. Thank you Mr. Sister Caroline

[@p3acefool]

Thank you so much for uploading this. It is amazing , great seminar!

[@siavashfirouzi]

So many of my questions were answered. The explanation was deep and complete. thank you

[@charlesje1966]

Thanks. That cleared up a lot of lingering question I had.

[@99kevin99]

Wow. Science Communication at its finest. Can you float a boat in "heavy oil" to limit vibration in some way?

[@RocketPropelledGuy]

Ok, now I understand how the holographic medium can store multiple angles, but I do not understand how the object beam carries the image information of something otherwise in the path of the object beam but was obstructed from contact by other matter. For instance if we have a cube and line it up perfectly with the object beam so only one side is illuminated without any of the light ever being capable of being perceived by the human being contacting any other side of the cube. It sounds like it apparently can still reconstruct the other sides it never contacted? Does it have to do with the edge of the wavefront, like the outer edge of the wave actually is actually continuing from the edge but because it is a wave and so small it then contacts the side of the object? But then how does that side get to the holographic medium? Have I misunderstood something?

[@MrRichDavid]

Good job Pete.

[@susanclark6987]

Thanks so much..great video...you explained it so well...im 63 and i think i got it! LoL

[@sqrt5]

any demonstrations of an illuminated shard from a shattered glass hologram reflecting the whole image?

[@martinam8057]

Hi Brian, you can see this here, where a laser replays the whole image from a point in the hologram, kzbin.info/www/bejne/iIrEeKVrhM6ih9Em48s

[@matty7771]

Martina Mrongovius Martina, what if I could make a hologram of a magnifying lens then pump another image through said magnification lens, what would happen? Thank you

[@progina]

@@matty7771 if a magnifying glass is part of the "scene" of the hologram, when you look "through" the magnifying glass within the hologram, you would see the magnified image of what is behind it. And as you change your perspective, the view through the magnifying glass changes perfectly. If your question is whether you can make a hologram of only a magnifying glass and then use that resulting hologram as a magnifying lens, the answer is a qualified "yes". In practice, you would be creating what is called a Holographic Optical Element, or HOE. Look it up. There are some drawbacks, such as chromatic dispersion and other effects that come into play, so HOE's need to be well thought out beforehand and, generally, won't be as efficient or qualitative as using a nice glass magnifying glass. But for certain application, HOE's are the way to go. For example in telecom systems that involve lasers, there is no chromatic dispersion since there's only one wavelength of light. The use of HOE's to do things like collimate a beam before it goes down a fiber is a very basic example. Rudy Berkhout was a pioneer of using HOE's as objects within his holograms. You can see some of his work at the beginning of the video or look him up.

[@leif1075]

Hiw is Princess Leia not a histogram? Isn't thst right? Why not?

[@MPMatTSRI]

Hello, Thank you very much for the presentation, I wish I was there personally. I have a question regarding the art aspect of some of the holograms at the beginning of the presentation at t=25-40 sec. I would like to learn more about the setup to produce such effects. Could you please send me a general guideline to make a hologram like then wave pattern at t=25 sec. or that repeating dot pattern at t=33, or rather the one at t=38.. I thank you again and hope to learn more

[@peterrogina9450]

Hello, Thanks for the comment. Rudy Berkhout was a great artist and inspiration to many holographers. He was doing the holograms you referenced at a time when color holography was relatively new so his ability to control color is very noteworthy. Also noteworthy was the fact that he was a pioneer using holographic optical elements as his artistic "objects". That implies that he created those elements as a first step in his process. He used many exposures, as was needed for the color, but, otherwise, I am not entirely sure of the details of his setups even though I've had the great opportunity to visit his lab. I would recommend posting a specific message to the Holograhy group on FB. Someone will likely get back with you. Good luck, Pete

[@helium73]

It seems that diffraction would destroy the image. That you would need the pattern to be greater than the wavelength so that light could shine through the hologram. Diffraction destroys information because it will take a ray of light and create a sphere from it. That's why a pinhole camera can't be smaller than the wavelength of the light passing through it. Holography was discovered by accident which means it was used long before anyone possibly figured out how it works. I'm interested in what sort of pattern occurs when in the film.

[@martinam8057]

hi Helium, the hologram structure causes lots of diffraction, reshaping the path of the light (usually a spot light) into an image.

[@rjjames9336]

YOU are crazy

[@rjjames9336]

There is no science what you say

[@rjjames9336]

BAD Science