SLM (spatial light modulator) made from a projector.

SLM is a very interesting device. It modulates light in space, either modulating the phase or the amplitude of light. There are plenty of uses for an SLM (search in Wikipedia).


The main goal of the post is to show such a device made from an ordinary video projector. There are scientific papers on how to do that (search for example "A low-cost spatial light modulator for use in undergraduate and graduate optics labs")

I made my SLM some years ago, and now is the time to use it. It was made from an old LCD projector shown in photo 1 (ASK C90) it is old and dusty but it works.




I removed the light bulb and I so changed the control circuit that it thinks that the light bulb is on. I took out the LCD modules (there are three for each RGB color, so three SLM :)

I bought extension cables to connect the LCD module to the device (photo 2), and I made a hole in the projector so that I could connect the LCD module outside the device.

We shine a laser on the LCD module and that's all you need to run SLM (photo 3)

If you have a diffraction image that produces an image, we display it on the computer screen (photo 4). And the image on the screen is shown in photo 5.

That's all for this post, the next step will be to create a program that calculates such a diffraction image, which is actually a hologram.


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