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laser pulse vs trigger pulse in oscilloscope

Started by Ken S. Tucker October 25, 2010
Thank you so much for your kind reply (john field  and bill
specially . bye the way  please be friend with each other ). Let me
clear the question actually the pulse width of the  square shape
pulse(trigger  pulse ) is 1 micro second. The laser pulse width is 100
nanoseconds and the time when the laser pulse starts is 3.7 micro
second from the start of the square pulse. The trigger pulse switches
the RF signal which is sent to the qswitch by Rf -driver on and off.
In the qswitch we have a quartz crystal when the RF passes through the
crystal it deflect the light and we don=92t have pulse. When the RF is
off we have laser pulse. So the pulse should be built in the interval
when we don=92t have RF it means in the 1 micro second interval. But it
has a delay.  I  guess that delay is because of crystal in  qswitch.
When the Rf apply to fused silica crystal in qswitch it takes a time
for rf to propagate through the  crystal.th rf speed in crystal  is
around 109ns/mm . so for our qswitch that have a  60 mm crystal it
takes 30=D7109 ns for rf pulse to reach in the middle of the crystal
which is around 3 micro second . and it is reasonable.  Is my  guess
right. Thank you again.
sorry the crystal is fused silica not quartz
On Oct 27, 9:14=A0pm, Abner Amber <amirg...@gmail.com> wrote:
> Thank you so much for your kind reply (john field =A0and bill > specially . bye the way =A0please be friend with each other ). Let me > clear the question actually the pulse width of the =A0square shape > pulse(trigger =A0pulse ) is 1 micro second. The laser pulse width is 100 > nanoseconds and the time when the laser pulse starts is 3.7 micro > second from the start of the square pulse. The trigger pulse switches > the RF signal which is sent to the qswitch by Rf -driver on and off. > In the qswitch we have a quartz crystal when the RF passes through the > crystal it deflect the light and we don=92t have pulse. When the RF is > off we have laser pulse. So the pulse should be built in the interval > when we don=92t have RF it means in the 1 micro second interval. But it > has a delay. =A0I =A0guess that delay is because of crystal in =A0qswitch=
.
> When the Rf apply to fused silica crystal in qswitch it takes a time > for rf to propagate through the =A0crystal.th rf speed in crystal =A0is > around 109ns/mm . so for our qswitch that have a =A060 mm crystal it > takes 30=D7109 ns for rf pulse to reach in the middle of the crystal > which is around 3 micro second . and it is reasonable. =A0Is my =A0guess > right. Thank you again.
The Q-switch works by using the RF excitation to turn the block of fused silica into a diffraction grating. The RF excitation propagates a mechanical - acoustic - wave through the block of silica creating alternating layers of compressed and rarefied silica which interact with the photons travelling through the silica as a diffraction grating http://www.rp-photonics.com/q_switches.html and - in more detail - on page 520 http://books.google.nl/books?id=3DRK3jK0XWjdMC&pg=3DPA520&lpg=3DPA520&dq=3D= Q-switch+fused+silica+RF&source=3Dbl&ots=3DsFXtdohotY&sig The acoustic wave is generated on one side of the block and absorbed on the other, so you would seem to be correct in associating your delay with propagation of the acoustic wave through the block. There are going to be other propagation delays in your system, but 3.7 microseconds is a couple of orders of magnitude longer than anything that I was thinking of. The PAL TV system relies on the propagation of a similar acoustic wave through a crystal to generate a 64 usec delay in a compact device http://alexandria.tue.nl/extra3/proefschrift/PRF1A/7706759.pdf This is a Dutch thesis, but the bulk of the text is written in English. -- Bill Sloman, Nijmegen
On Oct 27, 2:34 am, Bill Sloman <bill.slo...@ieee.org> wrote:
> On Oct 27, 5:38 am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > > > On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > > > > > This was posted in sci.physics.research. > > > > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote: > > > > > > > > Dear Friends > > > > > > > I want to do some experiment in pulsed laser. I attached output of a > > > > > > > laser to one channel of oscilloscope via photodiode to see the shape > > > > > > > of the pulse. then I attach the one output of RF trigger of the > > > > > > > qswitch to the other channel of the oscilloscope to see the square > > > > > > > shape pulse of the Rf trigger till now everything is ok I can see > > > > > > > both pulses. But I can't interpret the relation between two pulses. To > > > > > > > my knowledge when we have RF we shouldn't have any laser pulse and > > > > > > > when the RF vanishes we should have laser pulse . it means that when > > > > > > > we compare two pulses in the oscilloscope as soon as the square shape > > > > > > > trigger pulse vanishes the laser pulse must be appear but it appears > > > > > > > later in the train of the pulse . what is the problem ? > > > > > > > Is the measuring equipment is poor or it has theoretical problem. > > > > > > > Thanks in advance > > > > > > > To start I'm reposting that to > > > > > > sci . electronics . design > > > > > > Regards > > > > > > Ken > > > > > > PS: One guys there is really smart, I don't know about the rest, > > > > > > of the others. > > > > > > Presumably the Q-switch is being driven by periodic signal - you get a > > > > > burst of RF, then no RF, then another burst of RF in a pattern that > > > > > repeats itself exactly. > > > > > > The claim is that the laser pulse should appear when the RF has been > > > > > switched off. > > > > > > If the period being displayed on the oscilliscope screen is long > > > > > enough to include two or more bursts of RF on one channel, the laser > > > > > pulse being displayed from the other channel will show up between the > > > > > two bursts of RF - the precise time relationship depends on how the Q- > > > > > switch works. > > > > > > This doesn't sound like the sort of question that needs anybody really > > > > > smart to answer it. If the OP had given some detail about the laser > > > > > system and the Q-switch, there might be more that could be said by > > > > > someone sufficiently well-informed (though not necessarily all that > > > > > smart). > > > > > Bill Sloman, Nijmegen > > > > > I single handidly invented the optical world! (had some help though). > > > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km, > > > > watch the return on the scope, reckon dispersion, that's how the > > > > pulse base spread a bit, and from that 'ballpark' a max fequency, > > > > for that particular fibre media. > > > > Next thing we had to do was join and tap the fibre, cost was no > > > > object, except my pay. > > > > Obviously, I'm a bit rusty, so I posted this for those who might > > > > understand what the fella (OP from spr) is driving at. > > > > Bully for you. Why did we need to know that? > > > Sorry I missed your post Mr. Sloman, like most, we read the > > interesting peoples posts 1st and eventually get around to you. > > Dr.Sloman. > > > To your question, as I explained, I (we) did that sort of thing around > > 1980, measuring how square waves got rounded etc, but I didn't > > quite understand the 'jargon' of the OP. > > Do you understand it now again? > > I didn't see the OP's post as jargon. He obviously hadn't reflected on > the significance of what he was seeing - otherwise he would have told > us the time delay between the end of the RF pulse to the Q-switch and > the appearance of the laser pulse - but his description of what was > going on was explicit enough, if not particulalry detailed. > > If you have had the experience with optical signals that you claim, > you should be able to find out the propagation delay (from photo- > cathode to anode) of a fast linear-focussed photomultiplier tube, > which might well be relevant to the OP's query. > > -- > Bill Sloman, Nijmegen
Mainly we did science & technology. We fused a fibre (a few feet from Tx), that's a Y, off a Km fibre, then pulsed in a laser burst. Then we compared the return signals on a photo coupled 2 channel silly scope and measured time and dispersition, it was a 1980 yawner experiment. We acquired a lot of data, and then designed new & improved fibre optics. It's sleepy work. Ken
On Oct 27, 1:46=A0pm, John Fields <jfie...@austininstruments.com> wrote:
> On Wed, 27 Oct 2010 02:34:32 -0700 (PDT), Bill Sloman > > <bill.slo...@ieee.org> wrote: > >On Oct 27, 5:38=A0am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > >> On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > >> > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > >> > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > >> > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrot=
e:
> > >> > > > > This was posted in sci.physics.research. > > >> > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote: > > >> > > > > > Dear Friends > >> > > > > > =A0I want to do some experiment in pulsed laser. I attached =
output of a
> >> > > > > > laser to one channel of oscilloscope via photodiode to see t=
he shape
> >> > > > > > of the pulse. then I attach the =A0one output of =A0RF trigg=
er of the
> >> > > > > > qswitch to the other channel of the oscilloscope =A0to see t=
he =A0square
> >> > > > > > shape pulse =A0of the =A0Rf trigger till now everything is o=
k I can see
> >> > > > > > both pulses. But I can't interpret the relation between two =
pulses. To
> >> > > > > > my knowledge when we have RF we shouldn't have any laser pul=
se and
> >> > > > > > when the RF vanishes we should have laser pulse . it means =
=A0 that when
> >> > > > > > we compare two pulses =A0in the oscilloscope as soon as the =
square shape
> >> > > > > > trigger pulse vanishes the laser pulse must =A0be appear =A0=
but it appears
> >> > > > > > later in the train of the pulse . what is the problem ? > >> > > > > > Is the measuring equipment is poor or it has theoretical pro=
blem.
> >> > > > > > Thanks in advance > > >> > > > > To start I'm reposting that to > >> > > > > sci . electronics . design > >> > > > > Regards > >> > > > > Ken > >> > > > > PS: One guys there is really smart, I don't know about the res=
t,
> >> > > > > of the others. > > >> > > > Presumably the Q-switch is being driven by periodic signal - you=
get a
> >> > > > burst of RF, then no RF, then another burst of RF in a pattern t=
hat
> >> > > > repeats itself exactly. > > >> > > > The claim is that the laser pulse should appear when the RF has =
been
> >> > > > switched off. > > >> > > > If the period being displayed on the oscilliscope screen is long > >> > > > enough to include two or more bursts of RF on one channel, the l=
aser
> >> > > > pulse being displayed from the other channel will show up betwee=
n the
> >> > > > two bursts of RF - the precise time relationship depends on how =
the Q-
> >> > > > switch works. > > >> > > > This doesn't sound like the sort of question that needs anybody =
really
> >> > > > smart to answer it. If the OP had given some detail about the la=
ser
> >> > > > system and the Q-switch, there might be more that could be said =
by
> >> > > > someone sufficiently well-informed (though not necessarily all t=
hat
> >> > > > smart). > >> > > > Bill Sloman, Nijmegen > > >> > > I single handidly invented the optical world! (had some help thoug=
h).
> >> > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km, > >> > > watch the return on the scope, reckon dispersion, that's how the > >> > > pulse base spread a bit, and from that 'ballpark' a max fequency, > >> > > for that particular fibre media. > >> > > Next thing we had to do was join and tap the fibre, cost was no > >> > > object, except my pay. > >> > > Obviously, I'm a bit rusty, so I posted this for those who might > >> > > understand what the fella (OP from spr) is driving at. > > >> > Bully for you. Why did we need to know that? > > >> Sorry I missed your post Mr. Sloman, like most, we read the > >> interesting peoples posts 1st and eventually get around to you. > > >Dr.Sloman. > > Actually, comparing you to Dr. Hobbs leads to the inescapable > conclusion that 'Mr.' suits you better.
Pity about that. Despite the fact that it doesn't suit your little collection of self-serving delusions, I got the Ph.D. and earned the title Dr. Sloman.
> >> To your question, as I explained, I (we) did that sort of thing around > >> 1980, measuring how square waves got rounded etc, but I didn't > >> quite understand the 'jargon' of the OP. > >> Do you understand it now again? > > >I didn't see the OP's post as jargon. > > Neither did Ken. Did you miss the single quotes around jargon?
No, but I wrote them off as Ken S. Tucker being pompous again.
> >He obviously hadn't reflected on > >the significance of what he was seeing - otherwise he would have told > >us the time delay between the end of the RF pulse to the Q-switch and > >the appearance of the laser pulse - but his description of what was > >going on was explicit enough, if not particularly detailed.
> Back-pedaling, huh?
Try reading the recent post from Abner Amber, where he finally puts in some numbers. Once he was provoked into thinking about what was going on, he realised that the unspecified delay he was seeing almost certainly came from the acoustic wave propagation time in his Q- switch. Since you can't actually understand a lot of what I write, you do often see my clarifications as changing the message rather than making it clearer. That's you being stupid rather me "back-pedaling".
> >If you have had the experience with optical signals that you claim, > >you should be able to find out the propagation delay (from photo- > >cathode to anode) of a fast linear-focussed photomultiplier tube, > >which might well be relevant to the OP's query.
It's often around 30nsec, depending on the tube, the voltage across the tube and the length of the tube. In the event, about two orders of magnitude too fast to explain what the Abner Amber was actually seeing. -- Bill Sloman, Nijmegen
On Oct 27, 6:23 pm, Bill Sloman <bill.slo...@ieee.org> wrote:
> On Oct 27, 1:46 pm, John Fields <jfie...@austininstruments.com> wrote: > > > > > On Wed, 27 Oct 2010 02:34:32 -0700 (PDT), Bill Sloman > > > <bill.slo...@ieee.org> wrote: > > >On Oct 27, 5:38 am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > >> On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > >> > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > >> > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > >> > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > >> > > > > This was posted in sci.physics.research. > > > >> > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote: > > > >> > > > > > Dear Friends > > >> > > > > > I want to do some experiment in pulsed laser. I attached output of a > > >> > > > > > laser to one channel of oscilloscope via photodiode to see the shape > > >> > > > > > of the pulse. then I attach the one output of RF trigger of the > > >> > > > > > qswitch to the other channel of the oscilloscope to see the square > > >> > > > > > shape pulse of the Rf trigger till now everything is ok I can see > > >> > > > > > both pulses. But I can't interpret the relation between two pulses. To > > >> > > > > > my knowledge when we have RF we shouldn't have any laser pulse and > > >> > > > > > when the RF vanishes we should have laser pulse . it means that when > > >> > > > > > we compare two pulses in the oscilloscope as soon as the square shape > > >> > > > > > trigger pulse vanishes the laser pulse must be appear but it appears > > >> > > > > > later in the train of the pulse . what is the problem ? > > >> > > > > > Is the measuring equipment is poor or it has theoretical problem. > > >> > > > > > Thanks in advance > > > >> > > > > To start I'm reposting that to > > >> > > > > sci . electronics . design > > >> > > > > Regards > > >> > > > > Ken > > >> > > > > PS: One guys there is really smart, I don't know about the rest, > > >> > > > > of the others. > > > >> > > > Presumably the Q-switch is being driven by periodic signal - you get a > > >> > > > burst of RF, then no RF, then another burst of RF in a pattern that > > >> > > > repeats itself exactly. > > > >> > > > The claim is that the laser pulse should appear when the RF has been > > >> > > > switched off. > > > >> > > > If the period being displayed on the oscilliscope screen is long > > >> > > > enough to include two or more bursts of RF on one channel, the laser > > >> > > > pulse being displayed from the other channel will show up between the > > >> > > > two bursts of RF - the precise time relationship depends on how the Q- > > >> > > > switch works. > > > >> > > > This doesn't sound like the sort of question that needs anybody really > > >> > > > smart to answer it. If the OP had given some detail about the laser > > >> > > > system and the Q-switch, there might be more that could be said by > > >> > > > someone sufficiently well-informed (though not necessarily all that > > >> > > > smart). > > >> > > > Bill Sloman, Nijmegen > > > >> > > I single handidly invented the optical world! (had some help though). > > >> > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km, > > >> > > watch the return on the scope, reckon dispersion, that's how the > > >> > > pulse base spread a bit, and from that 'ballpark' a max fequency, > > >> > > for that particular fibre media. > > >> > > Next thing we had to do was join and tap the fibre, cost was no > > >> > > object, except my pay. > > >> > > Obviously, I'm a bit rusty, so I posted this for those who might > > >> > > understand what the fella (OP from spr) is driving at. > > > >> > Bully for you. Why did we need to know that? > > > >> Sorry I missed your post Mr. Sloman, like most, we read the > > >> interesting peoples posts 1st and eventually get around to you. > > > >Dr.Sloman. > > > Actually, comparing you to Dr. Hobbs leads to the inescapable > > conclusion that 'Mr.' suits you better. > > Pity about that. Despite the fact that it doesn't suit your little > collection of self-serving delusions, I got the Ph.D. and earned the > title Dr. Sloman. > > > >> To your question, as I explained, I (we) did that sort of thing around > > >> 1980, measuring how square waves got rounded etc, but I didn't > > >> quite understand the 'jargon' of the OP. > > >> Do you understand it now again? > > > >I didn't see the OP's post as jargon. > > > Neither did Ken. Did you miss the single quotes around jargon? > > No, but I wrote them off as Ken S. Tucker being pompous again.
Yo Willy, you're down a quart of Preparation H, my house is so small, if I was foreclosed, nobody could find it! Pompous is for rich people. Mr. Fields is right, 'jargon' in electronics is common especially as more acronyms, products and procedures evolve, example for Willy, 'open a window', what does that mean? ( take a moment and stop fondling your iPod). Is a "Q switch" the same as 'coming out of the closet'? Does your closet have windows? There's a lot of sementics. OTOH, having done fibre optical research, the issue seemed moot to me. Ken
On Oct 28, 8:17=A0am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
> On Oct 27, 6:23 pm, Bill Sloman <bill.slo...@ieee.org> wrote: > > > > > On Oct 27, 1:46 pm, John Fields <jfie...@austininstruments.com> wrote: > > > > On Wed, 27 Oct 2010 02:34:32 -0700 (PDT), Bill Sloman > > > > <bill.slo...@ieee.org> wrote: > > > >On Oct 27, 5:38 am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote: > > > >> On Oct 26, 7:52 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > > >> > On Oct 25, 7:26 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> wrot=
e:
> > > > >> > > On Oct 25, 9:42 am, Bill Sloman <bill.slo...@ieee.org> wrote: > > > > >> > > > On Oct 25, 5:36 pm, "Ken S. Tucker" <dynam...@vianet.on.ca> =
wrote:
> > > > >> > > > > This was posted in sci.physics.research. > > > > >> > > > > On Oct 24, 3:12 pm, Abner Amber <amirg...@gmail.com> wrote=
:
> > > > >> > > > > > Dear Friends > > > >> > > > > > =A0I want to do some experiment in pulsed laser. I attac=
hed output of a
> > > >> > > > > > laser to one channel of oscilloscope via photodiode to s=
ee the shape
> > > >> > > > > > of the pulse. then I attach the =A0one output of =A0RF t=
rigger of the
> > > >> > > > > > qswitch to the other channel of the oscilloscope =A0to s=
ee the =A0square
> > > >> > > > > > shape pulse =A0of the =A0Rf trigger till now everything =
is ok I can see
> > > >> > > > > > both pulses. But I can't interpret the relation between =
two pulses. To
> > > >> > > > > > my knowledge when we have RF we shouldn't have any laser=
pulse and
> > > >> > > > > > when the RF vanishes we should have laser pulse . it mea=
ns =A0 that when
> > > >> > > > > > we compare two pulses =A0in the oscilloscope as soon as =
the square shape
> > > >> > > > > > trigger pulse vanishes the laser pulse must =A0be appear=
=A0but it appears
> > > >> > > > > > later in the train of the pulse . what is the problem ? > > > >> > > > > > Is the measuring equipment is poor or it has theoretical=
problem.
> > > >> > > > > > Thanks in advance > > > > >> > > > > To start I'm reposting that to > > > >> > > > > sci . electronics . design > > > >> > > > > Regards > > > >> > > > > Ken > > > >> > > > > PS: One guys there is really smart, I don't know about the=
rest,
> > > >> > > > > of the others. > > > > >> > > > Presumably the Q-switch is being driven by periodic signal -=
you get a
> > > >> > > > burst of RF, then no RF, then another burst of RF in a patte=
rn that
> > > >> > > > repeats itself exactly. > > > > >> > > > The claim is that the laser pulse should appear when the RF =
has been
> > > >> > > > switched off. > > > > >> > > > If the period being displayed on the oscilliscope screen is =
long
> > > >> > > > enough to include two or more bursts of RF on one channel, t=
he laser
> > > >> > > > pulse being displayed from the other channel will show up be=
tween the
> > > >> > > > two bursts of RF - the precise time relationship depends on =
how the Q-
> > > >> > > > switch works. > > > > >> > > > This doesn't sound like the sort of question that needs anyb=
ody really
> > > >> > > > smart to answer it. If the OP had given some detail about th=
e laser
> > > >> > > > system and the Q-switch, there might be more that could be s=
aid by
> > > >> > > > someone sufficiently well-informed (though not necessarily a=
ll that
> > > >> > > > smart). > > > >> > > > Bill Sloman, Nijmegen > > > > >> > > I single handidly invented the optical world! (had some help t=
hough).
> > > >> > > Back in 1980, we'd tweek a pulse down a fibre coil, maybe a km=
,
> > > >> > > watch the return on the scope, reckon dispersion, that's how t=
he
> > > >> > > pulse base spread a bit, and from that 'ballpark' a max fequen=
cy,
> > > >> > > for that particular fibre media. > > > >> > > Next thing we had to do was join and tap the fibre, cost was n=
o
> > > >> > > object, except my pay. > > > >> > > Obviously, I'm a bit rusty, so I posted this for those who mig=
ht
> > > >> > > understand what the fella (OP from spr) is driving at. > > > > >> > Bully for you. Why did we need to know that? > > > > >> Sorry I missed your post Mr. Sloman, like most, we read the > > > >> interesting peoples posts 1st and eventually get around to you. > > > > >Dr.Sloman. > > > > Actually, comparing you to Dr. Hobbs leads to the inescapable > > > conclusion that 'Mr.' suits you better. > > > Pity about that. Despite the fact that it doesn't suit your little > > collection of self-serving delusions, I got the Ph.D. and earned the > > title Dr. Sloman. > > > > >> To your question, as I explained, I (we) did that sort of thing ar=
ound
> > > >> 1980, measuring how square waves got rounded etc, but I didn't > > > >> quite understand the 'jargon' of the OP. > > > >> Do you understand it now again? > > > > >I didn't see the OP's post as jargon. > > > > Neither did Ken. Did you miss the single quotes around jargon? > > > No, but I wrote them off as Ken S. Tucker being pompous again. > > Yo Willy, you're down a quart of Preparation H, my house is so > small, if I was foreclosed, nobody could find it! > Pompous is for rich people.
You may not be rich, but you can still mange to be pompous.
> Mr. Fields is right, 'jargon' in electronics is common especially as > more acronyms, products and procedures evolve, example for > Willy, 'open a window', what does that mean?
In what context?
> ( take a moment and stop fondling your iPod).
Don't have one.
> Is a "Q switch" the same as 'coming out of the closet'?
Scarcely. A "Q-switch" manipulates the "Q" of a laser resonator. If the "Q" of the cavity is left high, an individual photon bouncing backwards and forwards through the cavity can generate enough photons of the same phase and frequency - by stimulated emission - before it is lost to scattering or absorbtion to allow the appearance of a laser pulse. When the Q-switch is "on", the Q of the cavity is reduced and photons get lost faster than they can stimulate the emission of new photons. No laser pulse, and the energy stored in the population inversion in the lasing medium just sits there, waiting for the Q-switch to be turned off.
> Does your closet have windows?
Why do you feel the need to ask silly questions?
> There's a lot of sementics.
Sematics? "Semetics" might be a gay pun, but you are stupid enough that it is more likely to be a simple spelling error.
> OTOH, having done fibre optical research, the issue seemed moot > to me.
It sounds as if you were a technician, rather than a researcher, and are now suffering from delusions of grandeur. -- Bill Sloman, Nijmegen
On Oct 28, 2:45 am, Bill Sloman <bill.slo...@ieee.org> wrote:
> On Oct 28, 8:17 am, "Ken S. Tucker" <dynam...@vianet.on.ca> wrote:
...
> > Is a "Q switch" the same as 'coming out of the closet'? > > Scarcely. A "Q-switch" manipulates the "Q" of a laser resonator. If > the "Q" of the cavity is left high, an individual photon bouncing > backwards and forwards through the cavity can generate enough photons > of the same phase and frequency - by stimulated emission - before it > is lost to scattering or absorbtion to allow the appearance of a laser > pulse. > > When the Q-switch is "on", the Q of the cavity is reduced and photons > get lost faster than they can stimulate the emission of new photons. > No laser pulse, and the energy stored in the population inversion in > the lasing medium just sits there, waiting for the Q-switch to be > turned off.
Myself I'd just link to, http://en.wikipedia.org/wiki/Q-switching
> It sounds as if you were a technician, rather than a researcher
Like Einstein was a patent clerk? Ken
How can I compensate  the delay and  display both pulses
together  .displaying that I can measure the buildup time of the laser
pulse . I wanna  display  two pulses together like the picture of this
file
www.sintecoptronics.com/catalog/qswitch.pdf
On 10/29/2010 1:36 PM, Abner Amber wrote:
> How can I compensate the delay and display both pulses > together .displaying that I can measure the buildup time of the laser > pulse . I wanna display two pulses together like the picture of this > file > www.sintecoptronics.com/catalog/qswitch.pdf >
What equipment do you have available? Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net