Discussion:
where can I purchase 794.7 nm VCSEL for building CPT rubidium clock?
(too old to reply)
Mark Sims
2018-06-11 07:43:36 UTC
Permalink
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.
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Bruce Griffiths
2018-06-11 08:05:02 UTC
Permalink
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
Post by Mark Sims
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.
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Dana Whitlow
2018-06-11 10:52:21 UTC
Permalink
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
Post by Mark Sims
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.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
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Bruce Griffiths
2018-06-11 11:06:54 UTC
Permalink
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
Mark's description about how (most) green laser pointers work The better is a bit in
error, and is perhaps
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
Post by Mark Sims
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.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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Dana Whitlow
2018-06-11 11:29:58 UTC
Permalink
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
Post by Bruce Griffiths
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
Mark's description about how (most) green laser pointers work The better
is a bit in
error, and is perhaps
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
Post by Mark Sims
Well, no. Green laser pointers convert a rather high power 800 nm
laser
Post by Mark Sims
to 1600 nm in one crystal then divide it to 533 nm in another one.
The
Post by Mark Sims
physics and manufacturing of them is best described as black magic.
They
Post by Mark Sims
are cheap because China developed the process to grow the crystals in
bulk
Post by Mark Sims
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
Post by Mark Sims
$500.
------------------
It cannot be too much, given the fact that these are used in
green laser pointers.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
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Scott McGrath
2018-06-11 16:55:56 UTC
Permalink
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 <***@gmail.com> 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
Post by Bruce Griffiths
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
Mark's description about how (most) green laser pointers work The better
is a bit in
error, and is perhaps
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
Post by Mark Sims
Well, no. Green laser pointers convert a rather high power 800 nm
laser
Post by Mark Sims
to 1600 nm in one crystal then divide it to 533 nm in another one.
The
Post by Mark Sims
physics and manufacturing of them is best described as black magic.
They
Post by Mark Sims
are cheap because China developed the process to grow the crystals in
bulk
Post by Mark Sims
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
Post by Mark Sims
$500.
------------------
It cannot be too much, given the fact that these are used in
green laser pointers.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
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and follow the instructions there.
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