Fiber for Leica SP5 argon ion laser

[Aryeh Weiss]

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We are getting really low output from our argon-ion laser, especially at
488nm.

The other lasers appear to be ok.

So we thought that the laser is dying. However, this laser at its source
appears to be generating 170mW (!) multiline at 100% current, and about
75mW at 50% current. I find that hard to believe, but that is what we
saw with two different power meters (set to 514nm).

I will spare you many details, but the bottom line is that we found that
the fiber between the laser and the combiner has high loss, and we will
need to replace it. (Meantime, I installed a fiber form our old Biorad
1024, and this works).  But this does not explain something else that we
see -- a large difference between the 514nm and 488nm lines. We can get
2.4mW past the 10x objective at 514nm, but only 0.7 mW at 488nm.
Moreover, if I reduce the  argon ion laser current to 50%, I get 1.2mW
at 514nm, but 0.6mW at 488nm (in other words, the 488nm does not scale
with current as expected). Could be a problem in the AOTF (though I
check the AOTF tuning), but I cannot be sure because I could not isolate
the 488nm line before the AOTF (I need some single line laser filters).

So, I have two questions for the list.

1. Have you ever seen an otherwise healthy argon-ion laser lose its
488nm line? I imagine such a thing is possible if the dielectric mirrors
develop some defect that selectively affects 488nm.

2. Can anyone tell me where I can buy the single mode polarization
preserving fiber with the appropriate collimators on the ends (or get
the collimators separately and attach them)? I would have thought these
commonly available, because everyone uses them, but I have not been able
to find them. (Leica wants about $4750 for it, not including
installation, which I can do).

Thank you in advance for any assistance
--aryeh
--
Aryeh Weiss
Faculty of Engineering
Bar Ilan University
Ramat Gan 52900 Israel

Ph:  972-3-5317638
FAX: [phone]

[Pascal Weber]

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Leica is working with the company LASOS (Zeiss also) if you type on ther site  
you will not find the reference of the laser. I  have a similar problem with the
same laser and Leica ask me 15,000€ to change it. But the fiber has nothing.
The  laser flash if the power is over 50%. Have you checked if you had good
power before the fiber at 488nm ?

[Scot C Kuo]

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Yes, I experienced it with our new Nikon TIRF system, requiring a replacement laser (not fiber). The tech showed me how a short cavity argon laser (typical of confocal and similar systems) can lase differently for 488 vs 514.  The 488 line can go into donut transverse resonance mode (null exactly in the middle) while the 514 line has the normal Gaussian transverse modes needed to couple into a single mode fiber. A concave lens, color filter, and digital camera easily visualize the two modes from the same laser. Long cavity 'mainframe' lasers have adjustable apertures to tune transverse modes, but the short frame lasers have the aperture inside the laser tube and can't be adjusted in the field.

This behavior puzzled the heck for me until the tech explained and documented it.  Another symptom of the funny resonance is unusually high 514 power vs 488 power before the fiber (I've got the Ocean Optic spectral detector to measure power).

- Scot

============================================================================
...............Scot C. Kuo [phone]; email:[hidden email]...............
...Director, Microscope Facility, JHU-SOM, www.hopkinsmedicine.org/micfac...
..Assoc Professor, Biomedical Engineering & Cell Biology, www.jhu.edu/cmml..


----- Original Message -----
From: Aryeh Weiss <[hidden email]>
Date: Thursday, August 2, 2012 8:27 am
Subject: [CONFOCALMICROSCOPY] Fiber for Leica SP5 argon ion laser
To: [hidden email]

> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
> *****
>
> We are getting really low output from our argon-ion laser, especially
> at 488nm.
>
> The other lasers appear to be ok.
>
> So we thought that the laser is dying. However, this laser at its
> source appears to be generating 170mW (!) multiline at 100% current,
> and about 75mW at 50% current. I find that hard to believe, but that
> is what we saw with two different power meters (set to 514nm).
>
> I will spare you many details, but the bottom line is that we found
> that the fiber between the laser and the combiner has high loss, and
> we will need to replace it. (Meantime, I installed a fiber form our
> old Biorad 1024, and this works).  But this does not explain something
> else that we see -- a large difference between the 514nm and 488nm
> lines. We can get 2.4mW past the 10x objective at 514nm, but only 0.7
> mW at 488nm. Moreover, if I reduce the  argon ion laser current to
> 50%, I get 1.2mW at 514nm, but 0.6mW at 488nm (in other words, the
> 488nm does not scale with current as expected). Could be a problem in
> the AOTF (though I check the AOTF tuning), but I cannot be sure
> because I could not isolate the 488nm line before the AOTF (I need
> some single line laser filters).
>
> So, I have two questions for the list.
>
> 1. Have you ever seen an otherwise healthy argon-ion laser lose its
> 488nm line? I imagine such a thing is possible if the dielectric
> mirrors develop some defect that selectively affects 488nm.
>
> 2. Can anyone tell me where I can buy the single mode polarization
> preserving fiber with the appropriate collimators on the ends (or get
> the collimators separately and attach them)? I would have thought
> these commonly available, because everyone uses them, but I have not
> been able to find them. (Leica wants about $4750 for it, not including
> installation, which I can do).
>
> Thank you in advance for any assistance
> --aryeh
> --
> Aryeh Weiss
> Faculty of Engineering
> Bar Ilan University
> Ramat Gan 52900 Israel
>
> Ph:  972-3-5317638
> FAX: [phone]

[Aryeh Weiss]

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On 8/2/12 3:57 PM, Pascal Weber wrote:
>
> Leica is working with the company LASOS (Zeiss also) if you type on ther site
> you will not find the reference of the laser. I  have a similar problem with the
> same laser and Leica ask me 15,000€ to change it. But the fiber has nothing.
> The  laser flash if the power is over 50%. Have you checked if you had good
> power before the fiber at 488nm ?
>

Thanks to many people who replied, both on and off list.

To summarize:

I received a number of replies identifying the QI-Optiq kineFLEX fiber
as the fiber that Leia uses. I also received a suggestion to get teh
fiebr built by Oz Optics.

Concerning the laser, apparently it is possible for the 488 line to lase
into a different mode. I have not yet measured the power in the
individual lines before the AOTF, but I will need to do it. Probably I
will find a prism to disperse the lines so that I can measure them
separately.

--aryeh
--
Aryeh Weiss
Faculty of Engineering
Bar Ilan University
Ramat Gan 52900 Israel

Ph:  972-3-5317638
FAX: [phone]