The better ones use optically contacted crystals to avoid browning of the adhesive due to the high power densities of the 1064nm laser required for efficient frequency doubling.
Brue > On 11 June 2018 at 22:52 Dana Whitlow <[email protected]> wrote: > > > Mark's description about how (most) green laser pointers work The better 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. _______________________________________________ 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.
