Single beam transfers

[Arturo]

Hi all,

My first question in the 'new' forum... I am looking for a simple setup for demonstration/classroom purposes to make H1/H2 transfers involving only single beam setups.

I know this poses a great limitation... I was thinking that the transmission H1 should be a bypass setup, probably using a mirror to improve beam ratio and object lighting. But I cannot see how (or if) this could H1 could be copied into an image plane H2 at all using single beam setups...

Is it even possible? (regardless of the lots of quality limitations that would be involved, if possible, of which I am aware, like no beam ratio control, no collimation, etc...).

Thanks,

It's good to be back

[Ed Wesly]

Here you go:

http://edweslystudio.com/Pedagogy/7SBP/ ... e7SBP.html

3 variations of the same article, with 2 types of single beam transfers.

[Arturo]

What can I say, Ed?

I recall having discussed these at your studio, but could not find them. A question, though... what would you recommend? 3+4 (transmission H1 + achromat copy) or 6+7 (Denisyuk)?. I really like the achromatic property in 4, but...

[Guest]

I would suggest using a simple single beam reflection hologram, then proximity copy to make an image plane H2

In my setup I have been making single beam and split beam reflection holograms (H1)- flipping the H1 to then make a proximity copy H2

My setup is quite straightforward with the reference beam going down the center of my table passing through lenses to both expand beam and stear upward (30 degrees?) to my collimating mirror(CM). From the CM the expanded beam goes back toward the laser where it illuminates first plate then object.


_________________________ --------------------------------------- Collimating mirror
___________________ ------------------ _________________
LASER _______ optics__________________-------------------- object plate ____________________ ------------------

When making the H2, the H1 goes in the same plateholder (flipped upside down b/c top reference) and H2 goes between plateholder and CM

I do this using a 12inch CM and up to 8 x 10 plates both with single beam and split beams and both 1 and 2 simultaneous colors - for split beam application I use a beam splitter immediately before optics and second beam splitter underneath reference beam -between optics and object.
Of course with this setup you need to have a blocker behind the object so you do not see the laser behind the hologram
Depending upon the chemistry used to create the H1, you may have some shrinkage issues. I have generally not had shrinkage issues, but recently had a reflection hologram which looks good in white light, but needs to be turned to a funny angle to get a bright hologram with laser light. Consensus was emulsion shrinkage.
Just recently started doing some split beam H2s - with the reference beam illuminating both plates and split off object beams illuminating new objects between the plates. Good masking is required for this!

[Ed Wesly]

Do them both! They were the mainstay of the LFC Holo Workshops. The laser would be on a table, and the object and plate were on a square of steel on an inner tube on the other end. For the SBT master you need an extra mirror, but that's not too much more in the way of equipment. Plates were held to the steel plate by magnets.

The experiments are illustrated in Laser holography: Experiments you can do-- from Edison by TJ. There are some available from Amazon, I don't see how this seller http://www.amazon.com/Laser-holography- ... B000721UAU figures the book is worth a kilobuck, especially since they were meant to be given away! There are other more reasonable priced ones on Amazon, and one is also included in the ISDH proceedings bundle, http://www.amazon.com/International-Sym ... holography, which is a bargain even though it's $150.

Beam balance ratio is controlled in these set ups by positioning objects in different parts of the spread beam; for instance, when making the transmission transfer, the H1 is in the hot center of the beam and the weaker part of the Gaussian spread is the reference for the H2. You don't necessarily need collimation to make these holos, but the longer the throw the better, and we would get by with the typical laboratory bench of less than 2 meters.

Have fun!

[Guest]

The experiments are illustrated in Laser holography: Experiments you can do-- from Edison by TJ.

Yes, you are right! I have this lying around somewhere; yes, it was given for free with the integraph kit, I think

Beam balance ratio is controlled in these set ups by positioning objects in different parts of the spread beam; for instance, when making the transmission transfer, the H1 is in the hot center of the beam and the weaker part of the Gaussian spread is the reference for the H2. You don't necessarily need collimation to make these holos, but the longer the throw the better, and we would get by with the typical laboratory bench of less than 2 meters.

Great tip! Thanks!

[Arturo]

The experiments are illustrated in Laser holography: Experiments you can do-- from Edison by TJ.

Yes, I have this lying around somewhere, I will look for it. As you say it was actually included as a giveaway in the integraph holo kit, I think

Beam balance ratio is controlled in these set ups by positioning objects in different parts of the spread beam; for instance, when making the transmission transfer, the H1 is in the hot center of the beam and the weaker part of the Gaussian spread is the reference for the H2. You don't necessarily need collimation to make these holos, but the longer the throw the better, and we would get by with the typical laboratory bench of less than 2 meters.

And yet another great tip !

[Arturo]

Thanks "Guest", yes this is I understand, one of Ed's setups too!

But I take advantage of your message to ask a more general question...

When making the H2, the H1 goes in the same plateholder (flipped upside down b/c top reference) and H2 goes between plateholder and CM

When you say "(flipped upside down b/c top reference)" I am not sure I understand what you mean by " b/c top reference)". But this brings to me something that often confuses us, non English speakers: 'flip', 'rotate' and 'spin'...

This is what I understand for each, but am I right: Say that the reference beam is coming from the Y axis (front) [might be at an angle]; the black dot is at the 'front-top-right corner' if we were riding on the reference beam...

- flipping 180º would leave the dot at the back-bottom-right corner
- spinning 180º would leave the dot at the back-top-left corner
- rotating 180º would leave the dot at the front-bottom-left corner...

[CLICK TO SEE COMPLETE IMAGE]

[Din]

Arturo,
All three words are colloquialisms, they pretty much mean the same thing.

Which way you flip/rotate/spin the plate depends on the ref direction. To "copy" an image is to make a hologram of a hologram. In order to do this, the wavefront from the first hologram must form the "object beam" for the second (copy) hologram. There are then a number of situations:
1. Reconstruct the first hologram in the original setup, that is, simply replace the plate in the same position and orientation in which you recorded it. In this case, the image wavefront will diverge from the face of the first hologram (so the wavefront originates from a virtual source). The second hologram will then "receive" an image from a position behind the original hologram. So, if the original hologram/object distance is h, and the second hologram/first hologram distance is h', then the image will be at h+h' from the second hologram.
2. if you illuminate the first hologram with the conjugate of the original recording beam, then the image will be real and appear at a point h in front of the hologram. Now, the image from the second hologram will be h-h' (note sign is important. If h - h'' > 0, then the image appears behind the second hologram, conversely, if h-h' <0, the image appears in front of the plate. If h -h' = 0, then the image from the second hologram appears on the plate; this is "image-planed"). In order to reconstruct using the conjugate beam, you need to reverse the direction, and divergence, of the original beam.This is easily done by reversing the hologram, rather than reversing the beam. In this case, you "flip" or "rotate" or "spin" the original hologram. So, in terms of youre diagram, if the reference came in on the x-y plane at,theta degrees (ie E = E(0)*exp{ik{x*cos(theta) + y*sin(theta)} ), then, in order to reconstruct with the conjugate beam, you flip/rotate/spin so that your dot is on the left hand side on the back. That it, the dot has moved from (x, 0, z) to (-x,(0 - plate thicknes), z). In other words, you rotate about the z axis. If the reference for the first hologram is on the y-z plane ("overhead ref"), the you rotate about the x axis.
3. If you're reconstructing with the conjugate beam, then you need to be careful to alter the beam divergence also to create the conjugate divergence. However, for a collimated beam, the conjugate of a collimated beam is also collimated. Hence, if you intend to make a copy, it makes life easier if you start with a collimated beam.

[Ed Wesly]

Examining your diagram, there is a light arrow coming from the left at about 45 degrees. If this were the reference angle during the recording of a transmission hologram, the object would be where the letter Y is. Lighting this hologram as recorded would generate a virtual image of the object at Y, with the viewer’s eyeballs in the blank area of the graph paper.

Retaining the same reference beam, and spinning the hologram in the Z-axis, would replay a real image on the viewer’s side.

What would be the corresponding words in Spanish in your diagram?

I was trying to apply the aeronautical terms of roll, pitch and yaw to your diagram, but the direction of travel needs to be defined, which is not applicable in this case! (Motion being the #1 killer of holograms!)