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DMD with continuous angle adjustment - i.e. not only binary flipping

Dino Ott
Prodigy 20 points


Hi there, we are a group of researchers from the University of Copenhagen who are working on a new detection system for optical tweezers (if you are interested in this technique you can read more on http://en.wikipedia.org/wiki/Optical_tweezers ).

Currently we are evaluating the feasibility and cost of various optical layouts that we envisaged for the detection problem at hand. One of the solutions we are considering is based on integrating a DMD into our optical tweezers setup and we have a question concerning the possible deflection angles of DMDs.

We initially planed to use a 'standard' DMD (as e.g., http://www.ti.com/lit/ds/dlps025b/dlps025b.pdf ). However, by now we figured that it would be a big advantage for our application to work with a micromirror array that allows to adjust the reflection angle continuously compared to the binary flipping (e.g. -12deg to 12 deg), which is typically possible (at least with the products I have found so far...).

Does anybody know if TI (or alternatively another company) offers a micromirror array that allows for this fine positioning of the individual micromirrors?

The most important requirement for our application is that we are able to redirect several laser beam foci (which are impinging on neighbouring small areas on the DMD) into different directions (and ultimately to different optical sensors).

We haven't used DMDs in our lab before, so all help and suggestions are highly appreciated!

Many thanks in advance! :)

Dino

  • 0
    Prodigy 60 points

    I just saw this and thought maybe you would want to check out this paper demonstrating how to use the binary control for continuous steering.

    The paper :"Digital micromirror device for optical scanning applications" by Refai et al

    Hope this helps!

  • 0
    TI__Guru 54705 points

    Hello Dino,

    First, welcome to the DLP section of the TI-E2E Community.

    Micheal's answer is right on the money and the same direction that we would steer you (if you will pardon the pun).

    The challenge you will face with any spatially periodic array Spatial Ligh Modulator (SLM), whether it is a DLP DMD or not, is that the phase interaction of the coherent beam with the spatial period of the array will restrict light into discreet orders.  This means that you will have to research and see if the methodology of the paper that Michael referenced will work for your system to overcome these challenges.

    Fizix

  • 0 in reply to Fizix
    Prodigy 20 points

    Thank you very much for the fast replies and pointing me at the paper.

    With the paper at hand, we figured that what we are looking for is actually an analog micromirror array (as for example used in optical switching applications) since these mirrors can be individually tilted by an variable angle.


    Thanks again for helping our with this!

  • 0 in reply to Dino Ott
    TI__Guru 54705 points

    Hello Dino,

    As long as you have one beam per mirror in the array and do not have one beam hitting multiple mirrors in some kind of periodic array then it should work.

    Fizix.