By Phoenix:
” “Vertical Cavity Surface Emitting Laser” or simply vcsel.
As the name suggests, this laser emits it’s light from the surface of the laser rather than the edge
The light produced by a single vcsel is coherent, but the optical power is much much less than for typical edge emitting lasers used in traditional lasers.
However, and this is the big deal, because of how they are manufactured, it’s possible to have multiple vcsel emitters produced at the same time on the same chip so that an array of emitters can be created.
Each emitter may only be producing a few milliwatts of optical power, but an array of 100 emitters can produce a total output of a few hundred milliwatts of optical power.
So the total optical power produced by the laser now depends on how many individual emitters there are in the array.
As I said, the light produced by each emitter is coherent, but the light from one emitter is not coherent with the light from any other emitter,
Also, the light comes out of each emitter in a nice circular beam making lens design and manufacture much easier.
The beam of light from each emitter is not as concentrated as in an edge emitter and that, along with the fact that the emitting surface area from the whole array is much larger than for edge emitting lasers means the beam can never be as tight as that produced by an edge emitting laser.
For me, the lack of coherence and the much less concentrated beam makes vcsel illuminators a whole lot less dangerous than traditional edge emitting lasers.”
I will not put much info here but recently we have this new VCSEL technology that easily beats the best LED emitters but in IR spectrum (850nm).
Mildly driven VCSEL is about 3x intensity of lets say Osram 4715AS led emitter.
So I just hope that VCSEL technology will not stop in invisible spectrum and that it will advance to visible spectrum of light. And if 3x the intensity over best thrower LED will happen in possible visible spectrum of VCSEL technology that could be something that should be big boom in a flashlight world as well…
Frankly speaking it already is because IR light are also flashlights which work in invisible 850nm spectrum and can be seen by sensitive digital cameras and other night vision devices.
VCSEL looks like this:
3535 package
VCSEL does not require a back facet monitor like a diode laser; it can be driven like a LED, but at much higher power levels with a much lower drive current.
For example 0.7A driven VCSEL (not fitted on dtp board or overdriven) beats 2.1A driven Osram 4715AS LED… by 3x
So… Just imagine… If visible spectrum VCSEL laser diodes become available they will be big boom in flashlight world as well.