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Reflectivity of DMD for far-infrared light

George
Intellectual 440 points

Hi,

I  am thinking of  illuminating the DMD array with  far-infrared light, say wavelength between 4000nm to 100000nm. What's the reflectivity of DMD  for light within  these range?

Thanks

He

  • 0
    Guru 22270 points

    Hello Jin,

    Interesting question.  I don't know the answer to that one.

    Since the mirrors are aluminum (you'll have look up the exact composition) and there is data for visible, infrared and near infrared, then you could extrapolate for the far infrared reflectivity of the mirrors.  Also, if you are using that wavelength, you must be able to measure it somehow.

    I would think though, at that wavelength, the minimum temperature of the DMD would be an issue as well.

    I'm not any expert, just found the post...interesting.

    Thanks,

  • 0
    TI__Genius 9935 points

    Jin He,

    The mirrors of the DMD are indeed aluminum. However, the glass window of the DMD has nearly zero transmission beyond about 2700 nm. That is, it will be opaque to the wavelengths you have mentioned (4000nm to 100000nm). Also, the dimensions of each mirror in the array becomes very small with respect to these IR wavelengths, so that diffraction effects become very large - even if the window was transparent to these wavelengths.

    Can you say more about what you would like to accomplish?

  • 0 in reply to Pascal DLP
    Intellectual 440 points

    Pascal,

    Thank you for your explanation and useful information. 

    Regards,

    He

  • 0 in reply to Pascal DLP
    Expert 1040 points
    Pascal, sorry to dig out this old post -- I am wondering if your answer about zero-transmission beyond 2700nm is applicable to NIR DMD?

    Thanks, Bing