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DLP 7000 diffraction efficiency for 980 nm

user4153497
Prodigy 10 points

Dear TI applications team,

I am using DLP 7000(visible window, i.e. Corning 7056 or Corning Eagle XG) with 980 nm laser.

1. At flat state (inactivated), incident beam to the DMD was 330 mW, but reflected power was 220 mW including reflection at the window. (Incident angle was about 30~35 degree.) Is it right result? I'm wondering why the reflected power was so low.

2. Could you let me know DLP 7000's diffraction efficiency for 980 nm?

Sehwan Chang. 

  • 0
    TI__Guru 54320 points

    Hello Sehwan,

    Welcome to the DLP section of the TI-E2E community.  There is quite a bit more than just diffraction going on.

    First, the window transmission must be taken into account.  At 980 nm the transmission for one pass at 0º is down near 83%.  The incident beam would be near 24º which one pass is about 80%.   For both passes that would be about 66% [ 83% * 80% = 66.4%] which already accounts for your loss.  [ 330 mW * 64% = 219 mW ]

    The µ-mirror reflectivity and diffraction efficiency are pretty good at this wavelength.

    For more information on the window transmission please see this TI document -->  http://www.ti.com/lit/an/dlpa031c/dlpa031c.pdf

    Fizix