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Thread: set point temp for a 532nm dpss temp

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    Default set point temp for a 532nm dpss temp

    I was wondering what the ideal running temp for a 200mw green dpss, at some point I twiddled the wrong pot and threw off the operating set point, for a standard dpss that has only one TEC to the diode and crystals, what would a good operating temp generally be at, I need to stick a thermocouple at the diode/crystal and set the running temp, what is a generic temp that I should run at? or a good starting point to calibrate it to?

    Thanks
    Draco
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    As a general rule, the KTP wants to be warm and the diode wants to be cool.

    I have seen higher-power DPSS greens with the KTP heated to 40 degrees C, and a quick googling reveals that some designs heat the KTP to over 70 degrees C!

    My recommendation would be to put +5 volts DC on the modulation input, and then stick a power meter on the output and watch your power level while you play with the TEC driver (monitoring the KTP temperature at the same time). The conversion efficiency from 1064 nm to 532 nm is definitely affected by temperature, so you should be able to find a "sweet spot" where you get max power. Log that temp, lock the TEC settings, and you should be golden...

    Adam

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    Quote Originally Posted by buffo View Post
    As a general rule, the KTP wants to be warm and the diode wants to be cool.

    Adam
    so, what you're saying is dpss lasers are basically McDLT's..

    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

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    Quote Originally Posted by swamidog View Post
    so, what you're saying is dpss lasers are basically McDLT's..
    Never thought about it in those terms, but, yeah... Sort of!

    Also, it's killing me to know that I remember when you could still buy a McDLT.

    Adam

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    Keep in mind that a dpss laser temp tuned at cw 100% on, may yield disapointing results when it is being modulated.
    I suggest a 30Hz 50% dutycycle or even the standard ilda test frame for this purpose.

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    Good point Bart! I hadn't considered the effects of ramping up and down...

    Adam

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    The effect of 'sub-optimal' modulation results is most notable in dpss lasers with a single (or no) TEC.
    It becomes apparent in multi-projector setups, mismatches become most visible when using fades and/or yellow/orange colors

    The wavelength of the pump diode increases with temperature (its power), and the SHG efficiency is matched to this wavelength by heating it to a specific temperature.
    Dpss lasers in projectors are always modulated, so they perform better when tuned in that condition. (Even if it means a lower continuous-wave performance)

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