Color Holography Optics setup

Light and its behaviour and properties
kaveh1000
Posts: 56
Joined: Wed Jan 14, 2015 5:04 pm

Color Holography Optics setup

Post by kaveh1000 »

Milan, our thoughts are with you. We have all spent hours in the night in the lab and have had disasters. But we appreciate that holography is still alive, just, only because of the energy that people like you put into it. So we can't fix your laser, but feel your pain at least... Don't give up, dude. ;-)
MilanKarakas

Color Holography Optics setup

Post by MilanKarakas »

kaveh1000 wrote:Milan, our thoughts are with you. We have all spent hours in the night in the lab and have had disasters. But we appreciate that holography is still alive, just, only because of the energy that people like you put into it. So we can't fix your laser, but feel your pain at least... Don't give up, dude. ;-)
Thank you, kaveh. To me, it is better to stay away from the lasers. But, I love lasers and holography. Often I have nightmare - making emulsion and screwing it... Maybe I am ready for mental hospital.
Dinesh

Color Holography Optics setup

Post by Dinesh »

Maybe we should start to relate laser tragedies just to give Milan some support - a sort of dead-laser-support-group. Not as good as Dead-DPSS lasers forum, but may serve same purpose.

Our own story is that we have a large frame Argon laser that needs 2.5 gallons of water (12 l) per minute. We got this from the city water supply by directly connecting a hose to the laser power supply water input. Well, one day, the city decided to do some maintenance work on the water supply to the lab, so they shut down the water supply without telling us about it. When I realised the water supply was cut off, I rushed to shut down the laser, but too late. The laser never came back to life. We checked the transistors on the power supply, we checked the fuses, nothing! Then we passes a fluorescent bulb over the laser tube (to check ionisation of plasma), nothing! Finally, we feared the worst and sent the laser to our supplier (Cambridge Lasers, amazing, wonderful company! Run by an old holographer called Brian Bohan, who some of you may have come across - he worked at Advanced Holographics with Nick Phillips and Jeff Blythe). Anyway, Brian told us the laser tube was dead. He could repair it with a new tube, re-align everything and tweak it all for 17,000 dollars. Well, with little choice and with a customer on a governement project with a deadline of his own, we had to bite the bullet and simply spend 17,000 dollars on it.

Well, now the laser works very well. We have built a system that we call the "Frankenchiller". It's a large trashcan, filled with water, attached to a pump at the bottom and with a toilet float on the top. The city water fills up the trashcan until it's full to the top, then the toilet float cuts off the city water. Meantime, the water is fed into a pump at the bottom of the trashcan that maintains a steady 2.5 gallons of water to the laser. If the water supply is interrupted (by city workers suddently deciding to do a maintenace, for example!), a flotation device (ping pong balls in a narrow tube of water) drops until an electrical contact is made. This electrical contact is connected to the laser safety switch and shuts off the laser. Meanwhile, the water will still be pumped at 2.5 gals/min for another two minutes (long enough for the laser to cool down). At the end of this two minutes, another electrical system turns off the pump so as not to burn it out. It was tested for us one time when we were out to lunch and worked exactly as it was supposed to.

So, you see, Milan, it appears black and dark for a while, but with a little will power and a determination to carry on, it is possible to recover, get up and start again and find a solution.
MilanKarakas

Color Holography Optics setup

Post by MilanKarakas »

Dinesh wrote:Maybe we should start to relate laser tragedies just to give Milan some support - a sort of dead-laser-support-group. Not as good as Dead-DPSS lasers forum, but may serve same purpose.

Our own story is that we have a large frame Argon laser that needs 2.5 gallons of water (12 l) per minute. We got this from the city water supply by directly connecting a hose to the laser power supply water input. Well, one day, the city decided to do some maintenance work on the water supply to the lab, so they shut down the water supply without telling us about it. When I realised the water supply was cut off, I rushed to shut down the laser, but too late. The laser never came back to life. We checked the transistors on the power supply, we checked the fuses, nothing! Then we passes a fluorescent bulb over the laser tube (to check ionisation of plasma), nothing! Finally, we feared the worst and sent the laser to our supplier (Cambridge Lasers, amazing, wonderful company! Run by an old holographer called Brian Bohan, who some of you may have come across - he worked at Advanced Holographics with Nick Phillips and Jeff Blythe). Anyway, Brian told us the laser tube was dead. He could repair it with a new tube, re-align everything and tweak it all for 17,000 dollars. Well, with little choice and with a customer on a governement project with a deadline of his own, we had to bite the bullet and simply spend 17,000 dollars on it.

Well, now the laser works very well. We have built a system that we call the "Frankenchiller". It's a large trashcan, filled with water, attached to a pump at the bottom and with a toilet float on the top. The city water fills up the trashcan until it's full to the top, then the toilet float cuts off the city water. Meantime, the water is fed into a pump at the bottom of the trashcan that maintains a steady 2.5 gallons of water to the laser. If the water supply is interrupted (by city workers suddently deciding to do a maintenace, for example!), a flotation device (ping pong balls in a narrow tube of water) drops until an electrical contact is made. This electrical contact is connected to the laser safety switch and shuts off the laser. Meanwhile, the water will still be pumped at 2.5 gals/min for another two minutes (long enough for the laser to cool down). At the end of this two minutes, another electrical system turns off the pump so as not to burn it out. It was tested for us one time when we were out to lunch and worked exactly as it was supposed to.

So, you see, Milan, it appears black and dark for a while, but with a little will power and a determination to carry on, it is possible to recover, get up and start again and find a solution.
Thank you, Dinesh. After damaging laser, I decided to inspect why TEC driver can't put more than 200 mA onto peltier element. But, after some re-connecting, one of the transistor smoked out.

Seems that I should to stay away from soldering iron too.

And, I am sorry bothering you with my stupid problems. I will be more happy to reporting successful hologram making, rather than crying over myself.

Best--
milan--
142laser
Posts: 453
Joined: Wed Jan 07, 2015 10:14 am
Location: Tampa, FL

Color Holography Optics setup

Post by 142laser »

sounds like a shorted TEC...:( What kind of laser do you need? How much power? I will quote you our best price. :) Phil
MilanKarakas

Color Holography Optics setup

Post by MilanKarakas »

142laser wrote:sounds like a shorted TEC...:( What kind of laser do you need? How much power? I will quote you our best price. :) Phil
No, it is not shorted TEC, but some wire from the housing of the laser (+ve) come in contact with +5 V, thus 'bypassed' LM317 current regulator. So instead 290 mA, it gets lot more. It just blink and darkness remained.

I need decent 100 mW green laser. By decent I mean polarization ratio of about 100:1, and TEM00 mode. It will be good that it has good coherence length. Maybe I am asking too much. Last laser I damaged cost me just $12, but it has great coherence length. Only problem is that it give circular polarization, sometimes easy to 'rectify' with 1/4 wave plate. Okay, even after that plate some circular polarization remains, but it is easy to remove with polarizing beamsplitter cube.

Thank you for your help.

Best wishes,
milan--
Dinesh

Color Holography Optics setup

Post by Dinesh »

Jeffrey Weil wrote:I do remember some beer. But I couldn't have too much, I still had to drive back to L.A. What I most remember was your lab. I wish I had that much space.
Jeff, apropos of your remembering the size of our lab, yes it's pretty large. We have about 3000 sq ft of space divided into three offices, two labs, a large-ish warehouse and a ton of storage space (where we, in fact, keep computer parts. I appear to be the go-to guy for all the computer problems of all the pub folk, and they do make use of this resource, especially since it only costs them a pint of beer to fix their computer woes!).

At any rate, you may recall a conversation on FaceBook where you stated that artists were always on the lookout for lab space for their art projects. I suggested that I'd be happy to work with any artists that may require lab space, but I doubted they'd make use of my offer, since I have no idea how to communicate on the internet (back in the day, we had this concept of straight honest talk, rather than the pampering of delicate egos!). You mentioned that all I had to do was to offer lab space to artists and they'd grab at it! So, two people said thay'd make use of my offer in January. Well, it's January and so far not one of these "artists" has come forward. As I say, I have no idea how to converse with people in these ego-massaging days, but it seems as if you can offer the moon, but if you don't use the "correct" terminology with the "correct" syntax, no one will accept any offer you make! QED, I think!
Jeffrey Weil

Color Holography Optics setup

Post by Jeffrey Weil »

Hello Dinesh,

I'm sure they understood you perfectly, that's why they accepted your offer. What you probably didn't realize is when it came time to go to your lab they probably didn't have the money available, or maybe family matters got in the way, etc....There are lots of reasons they didn't show up. Did you ask they why?

I doubt the reason they didn't show was due to your communication skills.

Don't worry if you can't talk "art speak". They can. I'm sure you've heard something similar to this.

"No matter what subject your talking about, no matter how complex it is, if you can't describe it to a layman in a paragraph or two, then you don't really understand the subject yourself."

I would think art speak is the same.
Dinesh

Color Holography Optics setup

Post by Dinesh »

Jeffrey Weil wrote:I doubt the reason they didn't show was due to your communication skills.
We-e-e-ll. At one time, I actually went through a lot of trouble to make sure that anyone who wanted to work here had all the materials that we could provide; we once coated 40 plates because someone said they needed a lot of plates, but the person in question never showed up. Now, I expect that people who want to do their artwork here won't show up, so I don't coat anything. But, if/when they don't show up, I can ask one of two questions:

1. So, what happened? I thought you wanted to do some artwork here, but you never showed.

2. I am so sorry that we missed you. I was so looking forward to working with you because it would have been so much fun (and educational!) to collaborate on an art project with you. Maybe there were family problems? Please let's work together as soon as it's possible to work this out. By the way, I hope that nothing too bad prevented you from coming here. It will be fun working with you and I can't wait!

Now, there is no way on earth I'm ever going to sound like 2. My personality is most definitely 1! So, communication does seem to matter. If someone makes a statement committing themselves to something, I expect them to honour it. If they don't, they're not worth bothering about!
Jeffrey Weil wrote:"No matter what subject your talking about, no matter how complex it is, if you can't describe it to a layman in a paragraph or two, then you don't really understand the subject yourself."
]
Yes! Absolutely1 I pride myself that if someone genuinely wants to learn (rather than get "brownie points" by creating a sense of knowledge from mere vocabulary), I can explain everything from Fourier Transforms to the Higgs boson. But,
Jeffrey Weil wrote:I would think art speak is the same.
I have tried for years to get the artists to explain themselves, with absolutely no result! They honestly don't seem to understand themselves what they do! I mean:"What is art?", "Art is what we do", "Well, what do you do?", "We do art" This is explanation?! I think it finally hit home to me when all the tech folks at ISDH, to a man and woman, said that they didn't understand any of the "art" papers! I suspect that the artists probably didn't understand the tech papers either, but they don't seem to want to. If they hear <famous person> say something technical, they feel a sense of awe that they're hearing <famous person> say something they don't understand. After Nils' Abramson's paper on the relativity of holography, I went up to him and told him that almost all the derivations he gave were in Weyl's 1926 paper on Weyl Transformations. He asked, alarmed, "You mean this was done before!". I pointed him to Weyl's paper and he said he was going to look it up. But the artists lapped it up though, without understanding a word!

The problem is, there's no discussion of holography; this forum is simply a "help resource". I mean, here we are at the "optics" section. We talked about the Pennington/Lin procedure for eliminating cross talk by projection of a mask onto a plate. Is this possible with a lens system? What kind of a lens system? Can you do/has anyone done a Fourier Transform hologram using three wavelengths? If you illuminate a real object with coloured light, the shadow is the inverse colour. If you illuminate an object for a hologram, is the holographic reconstruction of the shadow also in inverse colours? It would be interesting to see a colour hologram complete with the shadows it threw. Liquid lenses are making a splash ( http://www.nature.com/nphoton/journal/v ... 006.2.html ). Can/has anyone used them for holography? There's a topic worthy of discussion!
qualitron
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Joined: Thu Dec 26, 2019 12:45 am
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Re: Color Holography Optics setup

Post by qualitron »

thanks for this valuable information.
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