IgorT
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- Oct 24, 2007
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I was thinking about my tiny portable peltier cooling system for my open can, and remembered, that these peltiers actually produce current, when a temperature difference is present between it's sides.
Then i thought, what if i were to mount one side to a heatsink and paint the other black.. If i would shine a laser on the black side, the peltier would start producing a certain voltage, relative to the power of the laser.. The peltier would have to be very small (15x15mm) to "feel" this tiny difference at all, but if i would then callibrate it using a known power LD, i could calculate the power of others, compared to the known ones...
I've been thinking of using small solar cells before, but they would only be able to compare between the same wavelength, since solar cells react differently to different wavelengths.. But heat is heat, regardless of the wavelength.
This could actually work for higher power lasers, but the resolution would be questionable... Even the tinyest peltier is capable of pumping 3.9W of heat, so 200mW would be very little to it.. Still, with an exact multimeter, the readings could be usefull, at least for comparing the power of different lasers.
EDIT: At first i thought different ambient temperature would give different results, but the ambient temperature is the same on both sides anyway.. Only the difference matters, and this would be caused by the laser beam.
In fact, i'm gonna test it now.
Any thoughts?
Then i thought, what if i were to mount one side to a heatsink and paint the other black.. If i would shine a laser on the black side, the peltier would start producing a certain voltage, relative to the power of the laser.. The peltier would have to be very small (15x15mm) to "feel" this tiny difference at all, but if i would then callibrate it using a known power LD, i could calculate the power of others, compared to the known ones...
I've been thinking of using small solar cells before, but they would only be able to compare between the same wavelength, since solar cells react differently to different wavelengths.. But heat is heat, regardless of the wavelength.
This could actually work for higher power lasers, but the resolution would be questionable... Even the tinyest peltier is capable of pumping 3.9W of heat, so 200mW would be very little to it.. Still, with an exact multimeter, the readings could be usefull, at least for comparing the power of different lasers.
EDIT: At first i thought different ambient temperature would give different results, but the ambient temperature is the same on both sides anyway.. Only the difference matters, and this would be caused by the laser beam.
In fact, i'm gonna test it now.
Any thoughts?