Introductions

Holography related topics.
Brian
Posts: 48
Joined: Thu Apr 07, 2016 8:31 am

Re: Introductions

Post by Brian » Sat Apr 09, 2016 3:44 pm

Hello

Last fall, the idea to make a hologram first came to me. So I found the Integraf website. I read how to make a single-beam reflection hologram, and thought "I can do that." I purchased plates and developing chemicals from Integraf and set up to make a three-color hologram of a shiny coin. I succeeded, sort of. So then I decided it was time to get my students involved.

I am a physics professor at a compass point university, I am happy to have found this forum. And so I'll share my story...

When I came to the uni at the turn of the century, I wanted to develop an experiment program that would provide research experience for our undergraduate majors. I asked a mentor for suggestions what to do. He said "do something with lasers or digital cameras. Those are cheap now, and what kid wouldn't want to play with lasers or cameras."

My optics education consisted of that one month at the end of a first course in undergraduate physics. My research background involved electron and X-ray optics, but no visible light optics. Then I read a paper about building an optical tweezers to manipulate micron-sized objects, and thought "I can do that." Cobbling together a modest startup, I got a laser, a camera, other optics and mounts, and an optics breadboard. There was no lab space, but there was a large closet full of useless stuff. So I cleared it out and installed the breadboard on a desk that was probably WWII surplus. Built the tweezers and it worked, sort of.

Long story, short... improve, modify, diversify into laser-induced spectroscopy on microscopic things. All this provides projects for my majors.

Along the way, about five years ago, my uni brings in consultants to help us science profs design labs for the "future science building". The future science building has been a promise for two decades before I came. This was like the third attempt at designing labs. So when they asked me how I'd set up a research lab, I said "no windows. Two vibration isolation tables with utilities (single-phase, 3-phase, air, vac, gas) and racks dropped from the ceiling, and with each table surrounded by blackout curtains. And more stuff. And a prep room. And oh yeah, put a cabinet right by the door to store laser glasses." Then I went about my business and promptly forgot about it.

A year ago, I toured the new science building, still under construction, for the first time. And I saw my lab, exactly as designed, all the way down to the UV-anti microbial safety glasses cabinet right by the door. Wow, dreams can come true! And so I moved equipment into the new playground this past summer. My current rig takes up a quarter of one table. But what about the other table?

What can one do with an empty optics table, spare lasers and optics, and some (much better than my startup) money? Last fall, the idea to make a hologram first came to me.

lobaz
Posts: 272
Joined: Mon Jan 12, 2015 6:08 am
Location: Pilsen, Czech Republic

Re: Introductions

Post by lobaz » Sun Apr 10, 2016 6:05 am

Hello, Brian,
welcome to the forum and good luck with your new lab!Nice story.
You can find many ideas on "what can one do with an empty optics table..." in e.g. Practical Holography by G. Saxby (and S. Zacharovas in the 4th edition).
What about building a holographic stereogram printer & image acquisition setup? Look at e.g. Zebra Imaging or Geola UAB webpages how an ultimate result may look like. This 4th edition of Practical Holography has even a chapter on "Do-It-Yourself Stereographic Holoprinter". It is definitely in the class "I can do that". You can also check the book "Ultra-Realistic Imaging: Advanced Techniques in Analogue and Digital Colour Holography" by David Brotherton-Ratcliffe and Hans Bjelkhagen for more details on holographic printers.

Petr

Ed Wesly
Posts: 501
Joined: Wed Jan 07, 2015 2:16 pm

Re: Introductions

Post by Ed Wesly » Sun Apr 10, 2016 7:44 am

You can get some ideas also from edweslystudio.com. In particular, check out the research blog, http://edweslystudio.com/Research/ResearchBlog.html, and the 7 Single Beam Projects http://edweslystudio.com/Pedagogy/7SBP/ ... e7SBP.html.

Have fun!
"We're the flowers in the dustbin" Sex Pistols

Din
Posts: 259
Joined: Thu Mar 12, 2015 4:47 pm

Re: Introductions

Post by Din » Sun Apr 10, 2016 9:17 am

Well, what you can do is pretty limitless. It's rather like saying, "I have access to a library. Now, what can I read?"

Holography basically stands on three legs: display, technical and commercial.

Display holography consists of producing a holographic image(s). To pursue this course, you need quite a lot of large optics, spatial filters and microscope objectives, perhaps a good digital display device, lots and lots of optical hardware (mounts, rods, post holders etc). Of course, there is the more (much more!) basic approach of what's called a "Single Beam Denisyuk"; for this all you need is, at the most basic, a plate holder, a glass lens and perhaps a mirror. I'm assuming that with a lab at your disposal you want to end up with something more sophisticated. This is not to say, of course, that you don't need to start "at the bottom" as it were. Display holography does tend to be very interesting to the students. We (Triple Take Holographics) run educational days and have had students from Palomar College in San Diego to the University of California San Diego (UCSD) and they've all loved making their own display pieces. The art students perhaps learned quite a bit (I throw in a lecture about Colour vision and the neurology of 3D vision, which fascinates the art students), but the physics students were already familiar with the ideas, so they didn't learn anything new; they were just fascinated at having made their own hologram. UCSD set up their own holography lab, much like yours, and I was asked to advise them in building it. In terms of reading material, as Petr has suggested, there is "Display Holography". However, more technical is Hariharan's book: http://www.amazon.com/Basics-Holography ... 0521002001.

Technical holography consists of using holographic principles to simulate optical functions. Thus, you can simulate a large, bulky lens/mirror system with a thin hologram, for example. This field is pretty topical at the moment for technical types. In the last few years more and more corporations and large entities have used holography for new display systems and new vision based architectures. There is quite a bit of money in this field, several companies have been granted million - and some, billions! - to research holographic solutions to implement new technologies. Now, with the advent of AR and VR, Microsoft's HoloLens and Google's "Google Glass",technical holography is beginning to rival electronics (well, perhaps that's going too far!). Technical holography has been projected to become a 10 billion dollar industry by 2020. The military has also got a great interest in holographic optics, from the early Heads Up Display (HUD) in the Air Force, to today's multi-spectral imaging methods and optical data collecting methods. Commercially, car companies such as Jaguar have begun to use HUDs in their more expensive models. So, it may be good for students to get involved there. However, note my earlier comment, display holography is by far a more fun thing to do! We ourselves are consultants to corporations wishing to pursue holographic solutions to technical problems ( http://www.triple-take.com/home.html ).

Commercial holography is largely security holograms, such as the one on your credit cards, as well as holograms on cards, books etc. This is a much more involved process than is probably possible with just a table and optics.

A quick word on "digital holography". This term is really a catch-all term for the use of digital devices, or approaches, to holography. In one incarnation, a digital device is used to generate a sequence of images, each of which is recorded as a thin line. When the entire sequence of lines is viewed at once, stereopsis produces a 3D image. This has been called "Lenticular" or "Multiplex" holograms. There is religious fervour in the naming of these types of holography, so I suspect others will weigh in as to alternative (and true!) names. Zebra ( http://www.zebraimaging.com/ ) carry out a variation in two dimensions where digital devices and software generate a 2x2 grid of imagery from digitally generated images. At another end, you can calculate the diffractive pattern of an image and then imprint it directly onto a medium. Thus, no need of lasers, optics etc. This is called CGH, and there are tutorials all over the internet ( http://www.eng.tau.ac.il/~yaro/lectnote ... ciples.pdf ).

You might also find a white paper by Melles Griot informative ( http://www.triple-take.com/publications ... ePaper.pdf )

Hope that gives you an overall idea of the possibilities. If I can be of any help, let me know.

By the way, I too am a physicist. I studied under Salaam at Imperial, London and Bohm at Birkbeck, London. My field was Theoretical Physics twenty odd years ago. Now it's diffractive optics. But, I'm still largely in the theory area. I calculate all the parameters and the geometries for the hologram and my wife actually sets up the hardware on the table. Like most theoreticians, I can't hammer a nail into a piece of wood without messing up!

Brian
Posts: 48
Joined: Thu Apr 07, 2016 8:31 am

Re: Introductions

Post by Brian » Mon Apr 11, 2016 9:50 am

Petr, Ed, and Dinesh, thank you for the warm welcome. I think you guys have filled my book request list for the year.

Ed, I have perused the forum for a while. So I have visited your website and read over the 7 single beam projects. I'm sure these projects will be the first things we try. I (and my students) do need to start with the very basics.

Petr, the project you suggests sounds like an interesting goal to work toward. Of course, first I have to learn what is a "holographic stereogram printer". But I'll get there.

Dinesh, thank you for the helpful overview. So one categorizes imaging the output of a diffraction grating in a hologram as "display holographics," whereas the creation of a diffraction grating hologram is "technical holographics." Fun to think about doing both!

Dinesh, somewhere here I read you were once offered a position at the theory institute in Trieste. I spent several days there on the Adriatic coast attending a conference. It has much better views than where I spent most my time in Trieste, at Elettra synchrotron way up in the hills. In my pre-optics career, I used X-rays to study ionization of atoms and small molecules. I did these post-docs in Manchester and Daresbury (England), Rome and Trieste (Italy), and Stony Brook and Brookhaven (NY, USA).

Din
Posts: 259
Joined: Thu Mar 12, 2015 4:47 pm

Re: Introductions

Post by Din » Mon Apr 11, 2016 2:14 pm

Brian wrote:
Dinesh, somewhere here I read you were once offered a position at the theory institute in Trieste. I spent several days there on the Adriatic coast attending a conference. It has much better views than where I spent most my time in Trieste, at Elettra synchrotron way up in the hills. In my pre-optics career, I used X-rays to study ionization of atoms and small molecules. I did these post-docs in Manchester and Daresbury (England), Rome and Trieste (Italy), and Stony Brook and Brookhaven (NY, USA).
Yes, that's right. Salaam was head of the institute (and UNESCO funded it), and he offered me a position as a theorist at Trieste. But he also said to me, "Don't get into theoretical physics"!

In them thar days, a PhD was basically an academic degree, designed to lead into academe. Any industrial entity disparaged PhD's and if you had one, no corporation would even look at you because it was thought that you were an ivory-towered academic with no understanding of the "real world". Salaam implied that I was a good theorist because I used imagination as well as strict mathematics - a sort of "pseudo-artistic" approach to theoretical physics. However, he also warned that if I did get into theoretical physics (or any academic physics, for that matter), I'd spend years at the college lecturer stage and I'd need a bit of luck to get "noticed". Perhaps he was expressing his own life, since initially, the Electro-weak theory was rejected by most theorists. At any rate, I was more interested in quantum gravity than particles, and I thought that there was something fundamental and deep in QM that people weren't quite seeing. So, Salaam said that if I felt that way, perhaps I should hie over to Birkbeck, where Bohm was teachimg. He said that Bohm's "Hidden Variable" approach might be what I was looking for. So Salaam wrote me a recommendation and I took it over to Birkbeck and joined Bohm's program.

<Edit>
By the way, seeing as how you worked on X-Ray diffraction, we had a PhD student from UCSD come in whose thesis involved superimposing a diffraction pattern onto X-Ray diffraction patterns from proteins. He (or his supervisor) wanted to see holograms of actual proteins. He didn't understand what "holography" was about, so he asked if he could just have an overview of holography. I set up a laser transmission geometry and explained reference beam-object beam to him, but I think it sort of passed over his head. I volunteered to let him make his own hologram, but he declined. I guess not everyone is fascinated by holography! This Thursday we're getting another PhD student, but his thesis is the evolution of the concept and the vocabulary of "holography" over the last 5 decades or so,from Gabor's 'wavefront reconstruction' to today's "holograms" as being these projection techniques.

Brian
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Joined: Thu Apr 07, 2016 8:31 am

Re: Introductions

Post by Brian » Mon Apr 11, 2016 6:41 pm

Yes, I have heard many times that physics PhDs aren't fit for any real jobs outside academics. May be true in my case.

Alas, X ray diffraction is the province of solid state physicists. Their beamtime at the synchrotron was measured in hours. Whereas we atom physicists studied ionizing collisions with very low densities of atoms. Our beamtime slog was weeks, running 24 hrs a day to accumulate enough statistics.

That is a bit of surprising with the PhD student. You'd figure anyone studying one light wave interference effect would be interested in another interference effect.

Din
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Joined: Thu Mar 12, 2015 4:47 pm

Re: Introductions

Post by Din » Tue Apr 12, 2016 12:25 pm

Brian wrote: That is a bit of surprising with the PhD student. You'd figure anyone studying one light wave interference effect would be interested in another interference effect.
Well, I think that a lot of people these days simply go through a PhD program in order to get the qualification, so as to get into the job market. They seem to think that they merely have to slog through 3 or 4 years of whatever their supervisor tells them to do, at the end of which they get a piece of poaper that they can trade for large salaries; no actual interest in the subject. My feeling is that education has now become a commodity.

I know of one PhD who wouldn't "believe" that a sinusoidal grating in the Raman Nath regime could only produce three orders. When I proved it to him, he still wouldn't "believe" it. I have three ways of proving that 2=1 (and so, by induction, there are an infinite numbers of ways of proving 2=1!). When I show it to undergards in maths, the usual reply is, "But, it doesn't" So, I say, "Of course it doesn't. But, where's the error" No attempt at finding it.

Brian
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Joined: Thu Apr 07, 2016 8:31 am

Re: Introductions

Post by Brian » Wed Apr 13, 2016 12:42 am

Din wrote: Well, I think that a lot of people these days simply go through a PhD program in order to get the qualification, so as to get into the job market.
For me to comment on this would be a bad idea. I have vested interest... yada yada.

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Wler1
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Re: Introductions

Post by Wler1 » Sun Apr 28, 2019 11:58 am

Hello, I just realized that the old forum has been revived. My old nick was wler but I couldn't reacivate the account, hence the new name.
I had paused my hobby for a couple of years but intend to get back to it soon, mostly developing SLM lasers etc. I got reinterested in tis when I heard about the PL530, this is to my taste. Sounds better than blue ECDL lasers....As soon I get hands on them, I will do some spectral and stability testing, if time allows. Perhaps developing a driver later, depending on the stability requirements. I will post progress on my blog: https://hololaser.wordpress.com

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