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DMD energy efficiency

Jinyang Liang10035
Intellectual 295 points

Hello, we are using DMD with the laser to do beam shaping. I have some questions about the power efficiency.

(1) DMD is designed for visible light but our laser is infrared (1064nm). Based on the energy efficiency measurement, we found the result is only about 20%. Is it normal??

(2) I tried to find sources to explain this big loss and found some material for window transmission. Is the data from this transmission from input to output (2 passes through the windows and one bounce off the DMD)?

(3) Does diffraction cause a severe energy loss? Can you tell me about the fraction of energy in the main order?

Thanks!!

  • 0
    TI__Guru 54320 points

    Helo Jinyang,

    The diffraction efficiency can cause this loss.  It depends on the specific DMD you are using.  The wavelength and incident angle as well as the tilt angle and mirror pitch of the device play an important role.  What DMD are you using?

     

     

  • 0
    TI__Expert 3385 points

    Jinyang,

    There are DMD's than can be purchased that have a NIR coating.  The curves shown on the website are for a single pass through the window AR coating.  However, the Window AR coating does not explain the loss of 80% of the light.

    Since you are using a laser, then diffraction efficiency can be a very important factor.   You may need to adjust the illumination angle or more capture more diffraction orders of the laser to increase your efficiency.

    I would encourage you to read the application note "using lasers with DLP".  It can be found here:

     

    http://focus.ti.com/dlpdmd/docs/dlpdesigncenterdetail.tsp?sectionId=61&tabId=2273