LEDs - Gallium Indium Nitride UV, violet, purple, blue, aqua, turquoise, green, white. Also Gallium Arsenide and others. New LED MUSEUM! GaN, InGaN, SiC, GaAs, GaP, GaAlP, ZnSe, flashlight, flashlights.VCSELs (Vertical Cavity Surface Emitting Lasers)
Now these guys are interesting... not something you'll see everyday.
Though they may look like ordinary LEDs, don't be fooled.
These lasers are VCSELs, or Vertical Cavity Surface Emitting Laserdiodes.
Although I know little about them, I have learned they seem to be less sensitive to damage than ordinary index guided laser diodes. They can be hooked up just like LEDs, with the correct resistor to limit the current to 15mA. The domed one on the left produces a surprisingly collimated beam at 850nm in the near infrared range, with a beam angle of approximately 1.5°.
With your eyes very well adjusted, you can make out a barely perceptible spot projected at a nearby target.
The one with the flat face produces a wider, 10° beam at 780.5nm; this is also visible to the eye as a dim red speck. The average CD player uses a laser with this wavelength, but not a VCSEL. Just a regular diode.
The picture on the left shows the narrow-beam VCSEL fired from 26" and without any additional lenses.
The one on the right is the flat-faced version, collimated by holding a lens in front of it while shooting the picture.
All digital cameras "see" infrared radiation as some color. The longer the wavelength, the bluer the spot.
Spectrographic analysis of the # TEL-2E20-007 VCSEL; emitting 3mW at ~780nm.
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