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Hologram!

flogged

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Here's my first successful hologram. This is a ~1 second exposure using ~75-100 mW DVD diode laser. Reflection hologram. I rested the film plate on top of some pocket change & items. Lens was removed from laser, which was located ~1 foot from film. The laser had been on for nearly 1/2 hour before exposing the film.

I'm going to attempt a transmission hologram next.

 
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Nice, job there for a first one. I know these aren't easy , but I've been having an interest in wanting to make one. Is their a easy way to make something like it with common things even if it's small? I heard these are very hard to do.
 

532 with Envy

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Congratulations on your first Hologram!!

These are really cool to work with....at some point when I have enough room to build a nice table i'd like to do the same.

Looking forward to seeing more of your work! I think everyone would enjoy seeing your table set-up as well.:beer::gj:
 

BShanahan14rulz

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don't let lack of a vibration-isolated table hold you back! I made holograms with glass plate films on my kitchen floor and it worked fine! I have to add, though, that the kitchen floor was linoleum right on top of the concrete foundation, and not near a busy road.
 

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Holograms are not difficult to create. The most difficult and nasty part is developing the film. To create the hologram I placed the glass square containing the emulsion on top of coins and exposed it to an uncollimated laser diode for about 1 second, then developed.

Area must be free from vibrations, and the laser stable and warmed up.

I used a piece of wood (plank) resting on top of bubblewrap, on the floor ,to hold the laser and stuff being holo'd. Shoestring. I'll provide a picture when I am successful creating a transmission hologram.

There are several inexpensive hologram kits via the internet if interested.
 
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532 with Envy

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I do have this kit....http://i-fiberoptics.com/laser_detail.php?id=2140 waiting for the right moment. I would prefer to make a hologram viewed by eye not using a laser(transmission?) and always like to do the best I can, trying to keep away from doing it on the floor;),,,,I was thinking a simple sandbox.

All good fun though, i'v loved the whole idea of holograms since the first I saw as a kid on National Geographic.:beer:
 

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Holograms Rock! I like the really intricate ones that change dramatically. Green is my favourite.
 

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Transmission hologram success!

Here's my simple hologram work area, for developing transmission holograms:



Everything is resting on the board, which in turn is laying on top of bubblewrap. I've propped my DIY laser 'brick' on the houseplant, and am aiming the uncollimated output towards the holographic film. The objects being photographed are in front of the holographic film. Transmission holograms are different than white light reflection holograms (the hologram of coins). After being exposed the holographic film will at best display a pattern of fringes. However after shining uncollimated laser light through the glass the object recreated. See video (marbles and glass trinkets):

https://vimeo.com/44147943

Unfortunately the video is not as impressive as viewing the actual hologram. There's much more depth to the scene than is apparent in the video, and the definition is much better.

These holograms are not difficult to create, though it's tedious work.

My DIY laser is a 16x DVD diode, consuming 125mA (~75mW). The pointer has no duty cycle and I've found the laser needs to 'warm up' for at least 15 minutes before the most defined holograms are created. An exposure time of only 1-2 seconds is required with a ~75mW laser.

Making these images is surprisingly addictive - try creating holograms instead of burning stuff!
 
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Sigurthr

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I picked up six PFG-01 holographic film plates and developer and I have NOT been having any success so far making holograms. Out of the six plates only one has any actual hologram on it, and it is only a partial. The good news is that I think I've figured out why - overexposure. I tried varying pretty much every variable to determine what was the issue before finally coming to that conclusion.

The best one was a 4 second exposure with uncollimated 50mW at a distance of 18 inches. I thought for sure that a 10 second exposure of 200mW diverged to a 5foot diameter beam from 10feet away (much lower energy density) would have done better but it appears to also be overexposed with no resulting image. Stable surface requirements prevented me from trying the 50mW laser from a greater distance, so the 200mW'er was the only other option.

I'm going to have to pick up another pack of film plates and give it a go. I'm going to work with the 50mW uncollimated laser at distances shorter than 3 feet. Again this is due to stable surface availability. I'm going to try exposure times shorter than 3 seconds. I just wish these film plates weren't so expensive.

One question - how the hell do you tell which is the emulsion side? I've been assuming it is the innermost facing sides relative to the orientation of how the packs of two are packaged. The documentation says the emusion side is "sticky" but neither side felt sticky on any of them.
 

electron

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@flooged

Congratulations on your Hologram, that it so cool; keep up the good work :gj: +1
 

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I picked up six PFG-01 holographic film plates and developer and I have NOT been having any success so far making holograms. Out of the six plates only one has any actual hologram on it, and it is only a partial. The good news is that I think I've figured out why - overexposure. I tried varying pretty much every variable to determine what was the issue before finally coming to that conclusion.

The best one was a 4 second exposure with uncollimated 50mW at a distance of 18 inches. I thought for sure that a 10 second exposure of 200mW diverged to a 5foot diameter beam from 10feet away (much lower energy density) would have done better but it appears to also be overexposed with no resulting image. Stable surface requirements prevented me from trying the 50mW laser from a greater distance, so the 200mW'er was the only other option.

I'm going to have to pick up another pack of film plates and give it a go. I'm going to work with the 50mW uncollimated laser at distances shorter than 3 feet. Again this is due to stable surface availability. I'm going to try exposure times shorter than 3 seconds. I just wish these film plates weren't so expensive.

One question - how the hell do you tell which is the emulsion side? I've been assuming it is the innermost facing sides relative to the orientation of how the packs of two are packaged. The documentation says the emusion side is "sticky" but neither side felt sticky on any of them.
What sort of laser are you using?

I've been using ~650nm red laser diodes. My laser is about 12-15 inches from the plate. Shining down at a 45 degree angle. Looks like this:


The ~75mW laser in the picture yields a 1-2 second exposure time.

It's critical that no vibrations be present in your area. That's why I put bubble wrap under the board and only do the work late at night (early morning actually) so there are few people moving about and little traffic.

According to integraf only 1 out of 10 laser diodes, especially high powered ones, reliably produce a good hologram (coherence length??).

Below is a picture of three laser diodes, 'raw' output (no lens):

The furthest laser is a 4mW laser diode. This was included with the integraf holo kit. Not one of my (10 second exposures) hologram attempts with this diode were successful. Whether this was due to the diode or vibrations in the area I don't know. The middle diode is my DIY 15mW 635nm laser - video camera seems a bit more sensitive to 635nm. This laser was used to reconstruct the transmission hologram for the videos. The DIY laser 'brick' (closest) is the 75mW laser I used to expose the hologram emulsion. You'll note the Sony diode has a much fatter ellipse (nearly circular, less of a stripe) which is very desirable for my setup. Every exposure with the laser brick has been good, after a 15 minute warmup. Because of adequate heat dissipation I can leave this laser on indefinitely.

Determining which side of the film has the emulsion is slightly difficult in the dark. I dip my finger into a glass of water and then tough a corner of the plate. The emulsion side will be a tad sticky. The orientation of the plate is important.

Good luck!
 
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Sigurthr

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Thanks! For the one that partially worked I was using a 50-100mW 650nm (unLPM'd burner-equivalent diode like yours) also in a radioshack brick, haha. My diode is 3.8mm and has a massive divergence, so I have a very large even spread. I used this on two plates, but only one came out (reflection, 2ft distance, 4sec exposure, "straight on" alignment). The one that did not come out was transmission, also "straight on", 10sec exposure. I haven't tried the 45degree overhead alignment yet because I don't have anything to set the laser up on (like your flower pot) that is stable enough. I have a mic boom/stand with a clip on it that I can use but it isn't nearly as stable.

Aye, vibration is critical, unfortunately I live next to (300ft away from) a major trucking route and 50ton gravel and coal trucks go by randomly 24hrs a day. It is enough that every surface in the house vibrates a noticeable extent. I've been able to time things decently enough to miss any trucks, but the flooring also creaks and moves a lot so I have to be careful to not move at all while exposing the plates. So far I don't think vibration has been an issue. Someone walking a room or two over is enough to cause a 1mm shift in even the most stable surface I have.

I think the reason most lasers won't work is frequency (wavelength) shift. Truly stable lasers are expensive, and even though Integraf claims their 5mW diode is frequency locked, it really is not. It simply uses APC output regulation to keep the temperature of the diode as level as possible. This isn't really the same as single frequency emission. Only Gas or DPSS lasers are frequency locked without high end equipment design. Warming up the laser ahead of time just relies on the fact that any wavelength shift should have happened already. I did this with my 200mW handheld but it didn't seem to make a difference (again, I think exposure times were too long anyway).

I tried a 650nm 200mW unlimited duty cycle handheld focused for max divergence (can't remove the collimation lens) on four plates initially and not a single hologram came out. I didn't realise it but I was also exposing them too long (10sec) as well. With this one wavelength shift should not have been an issue, the laser runs cool continuously and was on for many minutes reaching equilibrium. This laser also has a massively long coherence length due to the collimated output, so I don't think lack of coherence is an issue either. Two plates were transmission, two were reflection. I set up the reflection ones exactly as their instructions showed and there was zero movement between the plates and subject. There might have been miniscule movement between the laser and plates but none that I could detect while exposing. The transmission ones I could not set up as overhead 45 degrees because I wasn't using flat/short objects, but rather objects larger than the plate, so I tried a "straight on" alignment as pictured where the laser hits both the target and the plate, with the target and plate 90 degrees off from each other and the laser 45 degrees off from either one (centered in the 90degree angle). Again, none came out at all. There is no red tint like there is in my partially functional one from the 4s exposure with the other laser and all plates have a very *light* yellow tint to them. The partially functional one has a much darker tint to it.

When I get my next batch of PFG-01 plates (12) I'll do two test plates trying out various exposure times to see what works best. I'll have a straight on reflection alignment and will be using the uncollimated brick laser. I'm planning on going with a one second exposure for one plate and the other I'll do a "classic test plate" with 500mS, 1S, 1500mS, and 2S exposures in vertical bands. I have a feeling the >1S ones will not come out the best though, haha.

The only other variable I can think of messing things up is my safelight. I've been using diffused monochromatic 473nm blue light as my safelight. I pulled up the sensitivity chart from Slavich who makes these plates after examining all other variables and discovered that these plates are indeed sensitive to blue light. There is a dip in, but not a total lack of, sensitivity in the green 540nm region and that is it. The dip in green is only a few units below the sensitivity to blue, which is only <2 units below the peak sensitivity to red. So, it is possible my safelight is not so safe. In the next round I will be using far less light than I was with my safelight to rule out this as a cause of error.
 

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I don't have much experience making these holograms either. However if the laser is >50mW and closer than two feet from the hologram film I doubt you need more than a 2 second exposure.

The LM317 based circuit I'm using in the laser is very very stable. See this topic on how to build this simple regulator circuit from easy to find and inexpensive parts:
http://laserpointerforums.com/f42/diy-homemade-laser-diode-driver-26339.html

About the only way to assure the diode is not 'mode hopping' or frequency drifting is to lets its temperature equilibrate before exposing. Thus I leave the laser on for the 1-2 hours required to expose 6-8 plates, after an initial 10-15 minute warmup. Some of the laser regulators here (such as the flexdrive) may not be suitable as they oscillate/ripple slightly on a small time scale. Only 1-2 seconds are needed to expose the film, followed by nearly 10 minutes of development :( I don't use any sort of darkroom light. The film is developed in the darkest corner of the room, away from the laser. With dark adapted eyes there's just enough light in room (leaking though window blinds and from LEDs on appliances) to determine if the plate is dark or clear during development. When dropped into the 'A+B' catalysts the film plate will be rendered nearly opaque.. after bleaching it becomes clear again. See developer instructions.

I keep all the development chemicals in glass containers, use distilled water. I drop the film plate into the first chemical bath (A+B) within 10-20 seconds after exposing it, and develop. 1/2 cup of A & B (1 cup total) and 1 cup of bleach appears to be enough to develop 6-8 of the 2.5" plates. There's enough developer in one kit to develop at least 30 2.5" plates.





I open the film in the darkest part of the room, determine the emulsion side, then approach the laser with it behind my back. Block the laser with a piece of paper, position the film and expose. It's difficult to reliably do a < 1 second exposure this way.. raising and lowering a piece of paper. I'll probably expose another 6-8 plates later tonight.
 
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Sigurthr

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I see. Interesting that you're not using a darkroom.

For the super fast exposure times I'll be using a oneshot to drive the DDL based laser brick. Basically it is a 500mSec width square wave pulse driving a 2N222A transistor to turn on the driver. It should work well.

I agree about nonlinear drivers possibly having too much ripple for holography, that is quite possible.

Can you please try a "stright on" alignment (as described by Integraf)? You've had such great success making these I'm very interested to see if you can reliably produce with that method as well.
 

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I determined last night my optimal exposure is close to 2 seconds, from about 15 inches away. Exposures < 1 second were successful, though dim. Unfortunately the battery scene was underexposed and too shaded to be interesting. However, a brilliant hologram of my glasses:
https://vimeo.com/44758976

What's amazing about these holograms is how much information they contain. They will likely not ever be duplicated, at least not trivially.

Consider: The 01 emulsion has a resolving power of 3000 lines per mm (grain size of 40 nm!!). Thus a 2.5" plate (63 mm) has 189,000 'pixels' per side.. for a 35 GigaPixel image! Assuming 8 bits representing each dot, that's ~33 GB of information. However the situation is more complicated than this, as the emulsion is about 10 wavelengths thick, assuming a 650nm laser (emulsion is ~7 micrometers thick). The reality is a 3D interference pattern is created within the emulsion. So the actual amount of information in that tiny hologram is likely x10 above figure, or ~350 GB... and it could be > 1 TB of information as it's an analog, not digital, medium.

Now I begin to comprehend why holograms are used for security reasons as they are extremely difficult to duplicate. As well, holographic storage - to think over 1TB can be preserved in a 2.5" square.

Here's my development setup, below. This is dry - I staged the containers without development chemicals for picture. I contain the chemicals in old distilled water containers so they don't splash out while I'm developing the film in the dark. Those chemicals are not too caustic, though toxic - you want to avoid the catechol in the A+B without question. Development starts from lower left (A+B) and moves counter-clockwise till final rinse (blue container). When finished I roll up the garbage bag and throw everything out except the development trays.



Quite addicted to creating these amazing and haunting holograms!
 
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