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Original question:

About dispersion property of DLP3000

DLP7000UV: 13148

ADRIAN GHITA
Prodigy 10 points
Part Number: DLP7000UV
Other Parts Discussed in Thread: DLP7000

Hi,

I'm having a hard time compensating the dispersion from a DMD (DLP7000 0.7" XGA 1024x768) using a diffraction grating and an achromatic plano-convex lens. 

The entire setup is built as a DMD-based spectrometer, it contains 2 transmission diffraction gratings and 4 achromatic lenses and a SPAD. 

Any advice will be much appreciated. 

Many thanks

Adrian

  • 0
    TI__Guru 54175 points

    Hello Adrian,

    This would require a diagram of your setup.  Are you wanting to reverse the dispersion introduced by the DMD?

  • 0
    Prodigy 10 points

    Hi Fizix,

    many thanks for your message. Yes, I'm trying to reverse the dispersion introduced by the DMD. See below a schematic.  The diffraction gratings are identical. The second grating is intended is to compensate for the dispersion coming from previous diffractive elements.With the mirror, I'm trying to flip the angles, but I haven't managed to correct the angular dispersion from the DMD. 

     

    Adrian

  • 0 in reply to ADRIAN GHITA
    TI__Guru 54175 points

    Adrian,

    I have studied your layout and the only way I can think of to undo the dispersion is to introduce a prism that adds a roughly equal amount of dispersion after the DMD to undo it.   There is no way to change the dispersion from the DMD.   It is a fundamental property of the fact that the DMD is a periodic pattern that is effectively a grating.

    Beyond that I cannot think of a simple solution.

    Fizix

  • 0 in reply to Fizix
    Prodigy 10 points

    Hi Fizix, 

    apologize for the late reply. Many thanks for the advice.

    Kind regards

    Adrian