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Hi Joshua,
does not look good at all! Too bad...
We've been focusing some 200 mW at 480nm and even more at 532 nm without any
problems, but the chance of damaging lens depends on wavelength (of course
405 nm will be much worse) and on specific focusing of the beam. In TIRF you
usually have diffraction-limited spot in the BFP, if you focus on a lens
element, or even worse on a glue in a doublet or triplet, then ...
Indeed, the bubbles look like glue between lenses that have partially
separated. Sort of really, really bad luck. This can happen with any
widefield illumination with gaussian (diffraction-limited) beam, including
SIM and TIRF, but I've actually never seen that before...
In a "high power handling" lens I would avoid any glued lens multiplets, but
who knows what the vendors do.
Best of luck to your remaining eye (and objective lenses), zdenek
--
Zdenek Svindrych, Ph.D.
W.M. Keck Center for Cellular Imaging (PLSB 003)
University of Virginia, Charlottesville, VA
http://www.kcci.virginia.edu/
tel: 434-982-4869
Annual FRET Workshop: http://kcci.virginia.edu/workshop-2017
---------- Původní zpráva ----------
Od: Joshua Vaughan <[log in to unmask]>
Komu: [log in to unmask]
Datum: 27. 5. 2016 4:11:25
Předmět: objective lens laser damage
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We damaged an objective lens, a Nikon CFI Plan Apo Lambda 100X Oil 1.45 NA
lens on our homebuilt TIRF/STORM microscope. Has anybody seen this sort of
thing before? I'm interested to hear, if so. We will repair or replace it,
and if replacing I wonder what to get. More details are below.
Here is a link to a pic of part of the back focal plane. It has some dark
spots that look 'burned' and some stuff that looks like 'bubbles'.
http://i63.tinypic.com/mmemvl.jpg
Repairing this lens will cost >50% of a new lens so I want to decide whether
to repair or to just get something else. I'd prefer something with a higher
damage threshold but I was unsuccessful in getting data on lens damage
thresholds.
If replacing, what to get? I noticed three lenses online and I wonder what
is best for STORM and whether all have a similar damage threshold or not.
1. CFI Plan Apo Lambda 100X Oil 1.45 NA (current lens)
2. CFI Plan Apo Lambda DM 100X Oil 1.45 NA
3. CFI Apo SR TIRF 100X Oil 1.49 NA
I think the Lambda lenses are supposed to be lower background, though I've
never tested whether that is important or not. They are also Plan lenses,
but I'm not sure how important that is for the <40 micron regions we
typically image. The SR lens has a correction collar which might be useful
(?) when imaging a bit off the glass. The online information says the SR
lens has a PSF optimized for STORM which sounds good but I'm not sure what
it actually means. I don't have any damage threshold information about these
lenses. Oh, we are pretty sure the damage was caused when we sent ~120 mW at
405 nm was sent to the lens in EPI and later in TIRF. We plan to
substantially attenuate the laser in the future, which didn't need to be
that big anyway, but I am not sure how much to attenuate by.
Joshua C. Vaughan
Assistant Professor
Department of Chemistry
Box 351700
University of Washington
Seattle, WA 98195"
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