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  • TI Thinks Resolved

DLP9000: Maximum power for pusled laser

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Replies: 3

Views: 87

Part Number: DLP9000

I am looking at the white paper saying a maximum power of 25W/cm^2 can be applied for DMD chip. But for pulsed laser, it may be different becasue of high peak power. So I have the following questions:

1. For 10fs~100fs, 800nm laser with rep rate of 1MHz, is the heating effect almost the same as the continous laser with the same average power?

2. Does the array temperature changes according to different laser specs?

3. Finally, I want to know if 25W/cm^2 is a safe number that I can apply with the laser specs I mentioned in 1.

Thank you!

  • Hello Cheng,

    Welcome to the DLP section of the TI-E2E forums.  

    As mentioned in the paper, we do not know what the effect will be with pulse durations in the femtosecond range.

    The array temperature does change with wavelength of the laser.  Aluminum takes a dip in reflectivity near 830 nm and the micromirrors have aluminum in them, so that 800 nm may not be a good choice. 

    We suspect that the heating effect would be similar to a continuous laser, provided that the peak power in the pulses is not ablating mirror material, but we have no experimental data to verify it.

    We have revised many of our data sheets to emphasize array temperature rather than power.  If you apply 25W/cm^2 with insufficient cooling you WILL damage the array.  for 420 - 700 nm the power handling for continuous illumination is driven by heat load and cooling solution.

    What are you wanting to make or attempt?

    Fizix 

  • In reply to Fizix:

    Hi Fizix,

    Thanks for your reply. We are fastly scanning a line at ~300Hz on the DMD for patterning. The linewidth is very thin, while the dwell time for the line is very short. I am just wondering if this will cause severe heating that makes the mirror malfunction.

    Cheng 

  • In reply to Cheng Zheng:

    Cheng,

    I doubt the average heat load will be the problem, as mentioned if the duration is short enough and the power in the pulse is high enough, it can slowly ablate the top layer of metal each shot, eventually ablating too much material.

    Fizix

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