Mark's description about how (most) green laser pointers work is a bit in error, and is perhaps over-simplified- the reality is actually more fascinating yet:
First a diode laser operating at around 808 or 809 nm is used to optically pump a solid state laser which generates light at 1064 nm. This light is then frequency doubled with an intra-cavity nonlinear element to produce the final output at 532 nm. For all this to work the optical elements must be critically aligned, and to me the most amazing thing about the low selling price is how this alignment is effected so cheaply. One of these units I've opened up has the doubler crystal held down by a lump of cement on one side- it looks for all the world like it must have pushed into alignment and "held" there while the cement was cured. Green pointers made in this way are characterized by quite good beam quality and very little wavelength spread from unit to unit. However, they are generally quite delicate and ruined by mechanical shock. Although not commonly known, at least one outfit (Z-Bolt) is now selling "direct diode" green pointers, where there is just one laser which emits directly in the green, at around 515-530 nm. These are much more robust, operate well over a wider temperature range, but have the usual poor beam quality (non-circular beam with some residual astigmatism) characteristic of diode lasers made with simple collimating optics. And, the output wavelength spread from unit to unit is quite large. Dana On Mon, Jun 11, 2018 at 2:43 AM, Mark Sims <[email protected]> wrote: > Well, no. Green laser pointers convert a rather high power 800 nm laser > to 1600 nm in one crystal then divide it to 533 nm in another one. The > physics and manufacturing of them is best described as black magic. They > are cheap because China developed the process to grow the crystals in bulk > and crank out zillions of them for consumer products. > > I suspect that a 1600-ish nm to 800-ish nm converter is not a stock > consumer-quantity device and will cost a pretty penny or two... like a > red/IR laser diode can be had for 50 cents and a telecom VCSEL diode can be > $500. > > ------------------ > > > It cannot be too much, given the fact that these are used in > green laser pointers. > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
