wosoka

yeah, probably won't work What about optically active dyes ? Anyone heard of em? Someone said there are two kinds, ones photo bleach and decompose and others that don't decompose but need constant source of light as those bleach for only few nanoseconds. Haven't heard from him yet.

Can anyone tell me if such a setup will give the results I assume: DIAGRAM: https://i.imgur.com/s8RhE8S.jpg Assuming 1) the scanner can angle a beam anywhere on the circular off-axis mirror and 2) the off-axis mirror can be rotated as an the diagram to any angle needed, can the beam shooting at any point on it from the scanner be made parallel to the middle beam bounced off of the off-axis mirror?

nah, this is an optical shutter that is either completely transparent or opaque across the whole surface the question is not about the shutter itself but rather how to squeeze the liquid crystal gel properly in producing one.

What? This isn't related to anything else.

I need to make my own smart film for some experiments. https://www.youtube.com/watch?v=LIeXXfDOjjg I've read enough articles on it to know the required components, how they are mixed and applied. I have a 1:1 mixture of liquid crystal and UV curable resin and glass bead spacers that I need to apply between two ITO PETs and UV cure to bond all the layers together. Glass spacers are used to get unform thickness which is needed for uniform opacity/transparency. This will create a "smart film". This is probably done industrially by precision rollers and very powerful UV light to cure it immediately as it leaves the rollers, but I don't have access to such equipment. Any ideas what else I can try? If I squeeze the layers and release before UV curing I fear the thickness of the liquid crystal layer will increase back a little. So I probably need pressure applied while the UV glue inside the mixture is being cured by UV light. I coud squeeze the layers with a thick glass slab and use powerful UV LEDs to cure the liquid layer, but I fear the liquid leaked from the sides may adhere the glass slab to it. That could still be removed with an exacto knife but it may easily adhere to the baseplate as well, leaving it stuck between the two. If I apply some powder or oil which will prevent adhesion to the glass slab and/or baseplate, it may affect the flat surface of the slabs required to cause the spacers inside the mixture to create a uniform 20 micron thickness across the sheet, as the outer layers of the "smart film" are plastic (PET) and not rigid glass. But I may be wrong on this, just an assumption. Another option may be using some rigid material for a baseplate which doesn't get glue (UV curable resin) adhered to it. I am not aware of such material. I've already tried without glass spacers and perfect layer thickness and just hand squeezing but the fading speed and opacity is not uniform across the sheet which is a requirement for my experiments. Any ideas?

Thanks, If I can get 25% or more of the original light to pass and 90% or more of the original light to be blocked than it will do. I looked up "optical kerr effect" and looks like it would mess up any other wave besides a beam so looking through it would give false image. "Saturable absorption is a property of materials where the absorption of light decreases with increasing light intensity. " I'm not sure how such a material sheet would work here. Care to explain please?

What you are referring to is PDLC (polymer dispersed liquid crystal), it is either all opaque or all transparent. There was some research on making a PDLC with pixels but it would have the same issue as ordinary LCD for my use case. With both I can't achieve what I quoted above, which is making an area of a film become transparent or opaque by shining a beam on it. What I am looking for is similar to a beamsplitter used to combine beams, but in my case I need one beam to block an area of the other (bigger) beam, and beam position can change. Unlike a beamsplitter where they beams would get superimposed.

An LCD matrix or anything with pixels wouldn't do. But a sheet material which requires electrical field or similar to function would work.

Is there any material that if applied to or used as a film and illuminated by IR, UV beam or visible light beam or beam of specific polarization will become transparent or opaque in that spot and the opposite when not, and transition at fast rates (<= 8 ms)? Ordinary photochromic films are quite slow with 15 second transition to one state and several minutes to the other.

In all fairness you can't blame me for not mentioning something in my original post in a post after many other posts I made where I mentioned and linked to fast motors.

That will not solve it, as the red beam will be overlayed on the blue beam on the projection surface and produce a violet spot, rather than red. If LCD was instead used on the blue beams path to block where the red beam goes that could work, but the method ofacquiring the correct pixels to block on the blue would be complicated and not very accurate with an LCD matrix.

A bit of unsual scenario, I need to divide a video projection beam horizontally into two. Since the splitted beams in my diagram are treated as a separate beam they have to have their focus plane changed. Is that possible to do and how would one do it? http://image.ibb.co/jAu9x7/9241421.jpg If this helps the resolution of the original beam is pretty low by todays standards, 856x480 pixels.

Need to overlay beams by having one replacing the other where they intersect rather than have the beams be superimposed. this is what I want: https://i.imgur.com/F6HIYBl.png this is what I do not want: https://i.imgur.com/ylhMeEa.png This kind of beam combining can be either achieved by the "combiner" OR later in the setup by the "projection screen". Or in other words, having the original beam not reaching the projection surface is not the only solution as somehow not displaying the original beam on the projection surface even if it has reached it will also work. The colors of the beams are for illustration purposes, so are their positions. Position of the smaller beam can change. Is there any way at all to achieve this. Brightness not an issue so things such as polarizers can be used. Any ideas?

not really, not without DIY or decent speeds

As mentioned before with an actuator such as galvo scanner or pixel shifting actuator, not a mirror holder, by hand...

Do what? What is the mirror setup? With two rotating mirrors you can either rotate the beam in 2D or shift the beam in 1D. But shifting the beam in 2D with 2 mirrors? That's new to me, if this is what you do then please explain. Or do you mean a mirror attached to a device that can rotate in two axis rather than one?

You can't shift in two axis with just two rotating mirrors, you'll need four and the mirrors for the last two would have to get pretty big, for a diverging beam too big to be practical. Laser light show projectors all exclusively use galvo scanners, I've built some myself. For video projectors there's this but shifting amount is very limited and costs thousands. https://www.optotune.com/products/beam-shifting

Oh where do I even begin. I can say this is for pico video projection beam and I've tried laser scanners and while they are cheap (the "slow" ones) and easy to control, the distortion of the beam caused by angles of the scanner mirrors is hard to correct by undistorting the pixels in software and results in loss of resolution. Something which would be perfect would be to be able to offset the tiny projection beam without affecting its angle. I had some luck with a gantry system and stepper motors as well like in the CNCs but it was just not fast enough, although close. Well, the barrel or pincusion distortion may be corrected by a corresponding distortion lens before the scanners. But with this solution you seem to be not addressing the distortion of the beam which has bounced off of two scanning mirrors at an angle, I think.

Hi, that will introduce distortion to the beam. ...right?

I am looking for some mirror setup where rotation one or more elements in the mirror setup will allow to shift the beam along its axis. Two mirrors in a galvanometer scanner type setup work well for controlling the angle of the beam. Rotating risley prisms can be used to only offset the beam without changing its angle but the possible positions are limited. Dove prisms are great for rotating the beam along itself or rotate in a circular fashion if prism center is shifted. But as for offsetting (shifting) a beam along its axis from a (-1,-1) position to (1,1) without changing the angle of the beam, I can't find any setup which involves a rotating mirror rather than shifting mirror. But I feel there may be something missing from my limited optics knowledge.