Short lifetime of laser? Can "between lines" seq imaging shorten lifetime?

[Avi Jacob]

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Hi all,

We have been heavily using our SP8 confocal for 2.5 years now. Recently,
our 405 laser stopped being power-adjustable, (i.e. it's stuck ~2% power).
One effect of this is that we can no longer perform "between lines"
sequential imaging (because when going to the second channel, the 405
laser will not go down to 0, and thus still excite in the second seq too.
When doing "between frames", I can close the shutter for the second seq).

The local service and Leica said we need to replace it. As you can imagine
it's not inexpensive.
1. Is 2.5 years a reasonable lifetime for a solid state laser? (It's a
Lasos 405nm 50)
2. I usually use "between lines" sequences - does anyone think that the
constant lowering and raising the laser power can contribute to a shorter
laser lifetime? Say as opposed to "between frames", where the laser is on
for an entire frame. So multiple ups-downs, vs a single on-off.

Cheers,
Avi



--
Avi Jacob, Ph.D.
Head of The Kanbar Light Microscopy Unit
The Mina & Everard Goodman Faculty of Life Sciences
Bar-Ilan University, Ramat-Gan 5290002, Israel
Cell: 052-5802544 (call here first), Desk: 972-3-5317647
http://tinyurl.com/BIU-Microscopy

[Zdenek Svindrych-2]

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Hi Avi,

2.5 years is fairly short lifespan, but it happens. I have experienced very
few laser failures myself, so I can't give you a solid number. Since your
laser is not dead, but it seems like sort of a control issue, you might be
able to get it fixed (but I have no idea whether Lasos or someone else
services these lasers, and I can imagine quite long turn-around times).

I doubt "between lines" would affect the lifespan of the laser, I would be
more afraid that "between frames" will wear out the mechanical shutter.
Bear in mind that in a good confocal scanner the laser is blanked for the
inactive part of each line scan (retrace or "turning points") anyway.

Best, zdenek



On Mon, Mar 4, 2019 at 6:30 AM Avi Jacob <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Hi all,
>
> We have been heavily using our SP8 confocal for 2.5 years now. Recently,
> our 405 laser stopped being power-adjustable, (i.e. it's stuck ~2% power).
> One effect of this is that we can no longer perform "between lines"
> sequential imaging (because when going to the second channel, the 405
> laser will not go down to 0, and thus still excite in the second seq too.
> When doing "between frames", I can close the shutter for the second seq).
>
> The local service and Leica said we need to replace it. As you can imagine
> it's not inexpensive.
> 1. Is 2.5 years a reasonable lifetime for a solid state laser? (It's a
> Lasos 405nm 50)
> 2. I usually use "between lines" sequences - does anyone think that the
> constant lowering and raising the laser power can contribute to a shorter
> laser lifetime? Say as opposed to "between frames", where the laser is on
> for an entire frame. So multiple ups-downs, vs a single on-off.
>
> Cheers,
> Avi
>
>
>
> --
> Avi Jacob, Ph.D.
> Head of The Kanbar Light Microscopy Unit
> The Mina & Everard Goodman Faculty of Life Sciences
> Bar-Ilan University, Ramat-Gan 5290002, Israel
> Cell: 052-5802544 (call here first), Desk: 972-3-5317647
> http://tinyurl.com/BIU-Microscopy
>

--
--
Zdenek Svindrych, Ph.D.
Research Associate - Imaging Specialist
Department of Biochemistry and Cell Biology
Geisel School of Medicine at Dartmouth

[Craig Brideau]

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Hi Avi, what do you estimate the actual run hours were on the laser? You
say it was 2.5 years old, but were you running the system 60 hours a week?
Or barely using it? Estimated run time of these lasers can be anywhere from
2000-10000 hours. Modulating the laser will shorten the lifespan: Basically
the thermal shock of constantly switching it on and off stresses the laser
slightly, although if the laser is temperature stabilized properly it will
resist some of the effects from this. The drive electronics can also
overshoot when switching the diode on, which can impart electrical stress
on the diode as well. Properly damped driver circuits mitigate this, but it
is hard (expensive) to both squash overshoot and have fast on/off time from
the same circuit. Higher-quality diodes with tighter manufacturing
standards will also handle these effects better.

Craig


On Mon, Mar 4, 2019 at 4:30 AM Avi Jacob <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Hi all,
>
> We have been heavily using our SP8 confocal for 2.5 years now. Recently,
> our 405 laser stopped being power-adjustable, (i.e. it's stuck ~2% power).
> One effect of this is that we can no longer perform "between lines"
> sequential imaging (because when going to the second channel, the 405
> laser will not go down to 0, and thus still excite in the second seq too.
> When doing "between frames", I can close the shutter for the second seq).
>
> The local service and Leica said we need to replace it. As you can imagine
> it's not inexpensive.
> 1. Is 2.5 years a reasonable lifetime for a solid state laser? (It's a
> Lasos 405nm 50)
> 2. I usually use "between lines" sequences - does anyone think that the
> constant lowering and raising the laser power can contribute to a shorter
> laser lifetime? Say as opposed to "between frames", where the laser is on
> for an entire frame. So multiple ups-downs, vs a single on-off.
>
> Cheers,
> Avi
>
>
>
> --
> Avi Jacob, Ph.D.
> Head of The Kanbar Light Microscopy Unit
> The Mina & Everard Goodman Faculty of Life Sciences
> Bar-Ilan University, Ramat-Gan 5290002, Israel
> Cell: 052-5802544 (call here first), Desk: 972-3-5317647
> http://tinyurl.com/BIU-Microscopy
>

[daj1u06]

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Assuming you have an AOTF based system, is the laser actually being switched on and of at source at any time? Rather, doesn't the AOTF simply act as an electronic shutter and variable neutral density filter to let more or less of the light through (0-100%) as required. That might suggest that something is up with the UV AOTF system, rather than the laser itself? You should be able to see laser hours via the SP8's log files via a remote tech support call.

Dave Johnston, BIU Southampton.

[Piter_]

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Hi Avi.

To my knowledge in SP8 laser modulation is done by AOTF while laser is
running on constant power. I might be wrong as I don't have UV in available
setup.
May be your system is different. Is the laser easily accessible to check
its power output? In SP2 you could pull out fiber and measure it.
Best.
Petro.

On Mon, Mar 4, 2019, 19:20 Craig Brideau <[hidden email]> wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Hi Avi, what do you estimate the actual run hours were on the laser? You
> say it was 2.5 years old, but were you running the system 60 hours a week?
> Or barely using it? Estimated run time of these lasers can be anywhere from
> 2000-10000 hours. Modulating the laser will shorten the lifespan: Basically
> the thermal shock of constantly switching it on and off stresses the laser
> slightly, although if the laser is temperature stabilized properly it will
> resist some of the effects from this. The drive electronics can also
> overshoot when switching the diode on, which can impart electrical stress
> on the diode as well. Properly damped driver circuits mitigate this, but it
> is hard (expensive) to both squash overshoot and have fast on/off time from
> the same circuit. Higher-quality diodes with tighter manufacturing
> standards will also handle these effects better.
>
> Craig
>
>
> On Mon, Mar 4, 2019 at 4:30 AM Avi Jacob <[hidden email]> wrote:
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > Hi all,
> >
> > We have been heavily using our SP8 confocal for 2.5 years now. Recently,
> > our 405 laser stopped being power-adjustable, (i.e. it's stuck ~2%
> power).
> > One effect of this is that we can no longer perform "between lines"
> > sequential imaging (because when going to the second channel, the 405
> > laser will not go down to 0, and thus still excite in the second seq too.
> > When doing "between frames", I can close the shutter for the second seq).
> >
> > The local service and Leica said we need to replace it. As you can
> imagine
> > it's not inexpensive.
> > 1. Is 2.5 years a reasonable lifetime for a solid state laser? (It's a
> > Lasos 405nm 50)
> > 2. I usually use "between lines" sequences - does anyone think that the
> > constant lowering and raising the laser power can contribute to a shorter
> > laser lifetime? Say as opposed to "between frames", where the laser is on
> > for an entire frame. So multiple ups-downs, vs a single on-off.
> >
> > Cheers,
> > Avi
> >
> >
> >
> > --
> > Avi Jacob, Ph.D.
> > Head of The Kanbar Light Microscopy Unit
> > The Mina & Everard Goodman Faculty of Life Sciences
> > Bar-Ilan University, Ramat-Gan 5290002, Israel
> > Cell: 052-5802544 (call here first), Desk: 972-3-5317647
> > http://tinyurl.com/BIU-Microscopy
> >
>