- Joined
- Jun 19, 2014
- Messages
- 6
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I am just getting back into the laser hobby after a multi-year absence with my first purchase of a multi-watt 445 nm laser, and I am interested in trying to use the EG&G Electro-Optics 460-1A that I bought on ebay a while back to confirm its output, etc.
Now for the problems I know I need to do a LOT of attenuation to get a good reading since this meter is natively limited to 19.999 mw, I am just not sure what is the best way to get there as I am concerned about bleaching, etc if I use neutral density filters. Maybe multiple low pass beam splitters followed by a mid level ND filter?
Next issue there is something wrong with the ambient zero adjustment on my meter, the knob turns on the gear reduced pot, but does not change the display 0 (sensor does respond to varying light), can I safely assume I can ignore this tare zero and just use a calculator to adjust the base reading? The circuit board seems simple enough I may try to give it another visual check.
Finally the photo sensor head has multiple calibration frequencies, which includes 632.8 nm for helium neon, but does not include 445 nm (it does include 441.6 though) So my thought was to use a He-Ne laser in its native range say 5-10 mw to get an initial output reading (assuming its 2006 dated calibration is still good) set to 632.8,, then get another reading through the attenator setup and calculate the amount of attenuation, then switch the sensor head 460-2 to 441.6 mode and get a reading on the 445 nm laser. (this switch adjusts calibration of the photo sensors spectral response curve which I assum would be fairly close at 441.6 even though the response curve on photo cell sensors drop off quickly at the blue end) My concern here is of course spectral response of the attenuator setup changing from 632.8 nm to 445 nm. Any thoughts?
Thanks
p.s. I have a few lasers already, but all are red, mostly HeNe, but some diode lasers also. I may be able to scavenge a blue laser from a dead first generation Samsung blu-ray player, but I don't know its output level, and given the already steep drop off curve at the blue end of the spectrum and no calibration setting near the blu-ray laser frequency I would probably just be trading inaccuracy in the detector vs closer spectral response in the attenuator
Now for the problems I know I need to do a LOT of attenuation to get a good reading since this meter is natively limited to 19.999 mw, I am just not sure what is the best way to get there as I am concerned about bleaching, etc if I use neutral density filters. Maybe multiple low pass beam splitters followed by a mid level ND filter?
Next issue there is something wrong with the ambient zero adjustment on my meter, the knob turns on the gear reduced pot, but does not change the display 0 (sensor does respond to varying light), can I safely assume I can ignore this tare zero and just use a calculator to adjust the base reading? The circuit board seems simple enough I may try to give it another visual check.
Finally the photo sensor head has multiple calibration frequencies, which includes 632.8 nm for helium neon, but does not include 445 nm (it does include 441.6 though) So my thought was to use a He-Ne laser in its native range say 5-10 mw to get an initial output reading (assuming its 2006 dated calibration is still good) set to 632.8,, then get another reading through the attenator setup and calculate the amount of attenuation, then switch the sensor head 460-2 to 441.6 mode and get a reading on the 445 nm laser. (this switch adjusts calibration of the photo sensors spectral response curve which I assum would be fairly close at 441.6 even though the response curve on photo cell sensors drop off quickly at the blue end) My concern here is of course spectral response of the attenuator setup changing from 632.8 nm to 445 nm. Any thoughts?
Thanks
p.s. I have a few lasers already, but all are red, mostly HeNe, but some diode lasers also. I may be able to scavenge a blue laser from a dead first generation Samsung blu-ray player, but I don't know its output level, and given the already steep drop off curve at the blue end of the spectrum and no calibration setting near the blu-ray laser frequency I would probably just be trading inaccuracy in the detector vs closer spectral response in the attenuator
