diode laser wavelength 620/650/660 ??

First posting: Sun, Jan 14, 01 09:37:03 PM

dave battin

what wavelength laser is your cutoff..iv heard above 650 film sensitivity drops off....any comments.

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Colin - Tue, Feb 13, 01 10:30:44 AM
Acording to Frank's web page the longer wavelengths are less visible. Your eye can not see the image as well. Some laser pointer sales page says 635nm is 3 times more visible than 680nm (as a spot) but I can't find the reference right now. 206.81.100.122

Colin - Wed, Mar 28, 01 12:35:09 AM
I have been talking to a laser diode manufacturer. According to Will Houde-Walter speaking of higher powered doides "We have found that a short wavelength diode laser such as a 635nm-15 mW tends to be broader in line width as the current density is higher and will allow other spectral lines to compete." Food for thought. 64.167.150.183

Jerry - Fri, Dec 20, 02 12:36:45 PM
What are you using the laser for? Human detection or electronic detection?Typical human eye response is most efficient at about 507nm in low-light conditions, and at 555nm in "daylight" conditions. So, the lower wavelength is visually more efficient. But if you are using the laser to be detected by a silicon detector, the longer wavelength in more efficient, as silicon responsivity peaks at about 800nm to 850nm, dependng upon whether its a photo diode (800nm) or photocell (850nm). If you are sending the light through an optical fiber, the fiber attenuates to lower (635nm) wavelength more than it does the 680nm wavelength. If this is purely for human visiual purposes, stay with the lower (635nm) wavelength, as the human eye efficiency more than makes up for the fiber attenuation. If you using a silicon or Germanium detector to pick up the light, use the longer wavelength. If you are using a selenium or cadmium sulfide photocell as the light detector, their response is slightly better at 635nm than it is at 680nm. 65.198.100.66


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