Re: [time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
For experimental use you are probably better advised to use a dye laser or a Fabry-Perot laser as both are available on the surplus market and both are ‘tunable’ and leave the VCSEL till you have a functioning prototype On Jun 11, 2018, at 4:29 AM, Dana Whitlow wrote: I should have written more clearly- the adhesive in question was *not* in the optical path. As is usual, variations are possible, one supposedly being that the crystal that lases at 1064 nm is also doped with something to make it nonlinear (so I've read). I kind of have my doubts over this, however it seems like asking too much of a single substance to do "double" duty without some unwanted compromises. Dana On Mon, Jun 11, 2018 at 6:06 AM, Bruce Griffiths wrote: > 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 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 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 -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts >> and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
I should have written more clearly- the adhesive in question was *not* in the optical path. As is usual, variations are possible, one supposedly being that the crystal that lases at 1064 nm is also doped with something to make it nonlinear (so I've read). I kind of have my doubts over this, however it seems like asking too much of a single substance to do "double" duty without some unwanted compromises. Dana On Mon, Jun 11, 2018 at 6:06 AM, Bruce Griffiths wrote: > 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 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 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 -- time-nuts@febo.com > > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > > > mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
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 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 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 -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > > mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
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 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 -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
PPLN (Periodically poled lithium Niobate) is the frequency doubler of choice for such applications however it needs to operated in a temperature regulated oven. To achieve efficient frequency doubling the input light needs to remain in sync with the frequency doubled output light as they propagate through the frequency doubler. The frequency doubler Crystal optical dispersion and directional dependent propagation ensures that a crystal aligned for 164/532nm operation is unlikely to function effectively for 1680/890nm operation. PPLN however works well over a wide bandwidth. Bruce > On 11 June 2018 at 19:43 Mark Sims 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 -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
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 -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
