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Fwd: objective lens laser damage

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Martin Wessendorf-2

Fwd: objective lens laser damage

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I was asked to post this note on behalf of Dr. Alexander Asanov--

Martin Wessendorf

-------- Forwarded Message --------
Subject: objective lens laser damage
Date: Fri, 27 May 2016 20:19:50 -0400
From: Alexander Asanov <[hidden email]>

Dear Sripad:

Inclusions and other inhomogeneities, such as bubbles and irregularities
of refractive index are inevitable imperfections for all optical
materials. See for example Corning specifications for optical quality
silica
https://www.corning.com/media/worldwide/csm/documents/5bf092438c5546dfa9b08e423348317b.pdf.
Note that different grades contain different concentrations of inclusions.

We work with similar lasers and incidentally have similar problems with
lenses, couplers, and even recently lost a fiber cable, likely due to
its solarization; the fiber successfully served for several months
before. More often these problems happen at interfaces. Dirt, as Dr.
Wessendorf mentioned, is often an initiator. As soon as small damage
occurs, the problem typically escalates. Lens glue appears to be the
second most frequent source. 405 nm is certainly more damaging to the
glue than 647 of the same power.

If you focus a 1W laser into a 10-micron spot, you will get ~1 Mega
Watt/cm^2 intensity (10^6 W/cm2), which is huge, laser-cutting
intensity. Focusing 60-100 mW into a 30-micron spot also produces an
intensity, which may be sufficient to burn the lens glue.

Best regards,

Alexander N. Asanov, Ph.D.
President, TIRF Labs
106 Grendon Place
Cary, NC 27519
[hidden email] <mailto:[hidden email]>

www.tirf-labs.com <http://www.tirf-labs.com/> www.TIRFmicroscopy.com
<http://www.tirfmicroscopy.com/>

*Subject:*

Re: objective lens laser damage

*From:*

S Ram <[hidden email]>

*Reply-To:*

Confocal Microscopy List <[hidden email]>

*Date:*

Fri, 27 May 2016 14:31:22 -0700

*Content-Type:*

text/plain

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*****

The bubbles is something that I observed years ago (postdoc days) even with

dry lenses (20x PApo; Zeiss) that has never been illuminated with a laser.

At that time, we suspected that someone accidentally used oil on the dry

lens and forgot to wipe it off and was never noticed for a very long time.

It is possible that it could well be that something internal was damaged.

Sripad

On Fri, May 27, 2016 at 10:41 AM, John Oreopoulos <

[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* <http://www.imgur.com/> and include the link in
your posting.

> *****

>

> Do you really need these high laser powers for your application?

>

> John Oreopoulos

>

> > On May 27, 2016, at 11:42 AM, Glen MacDonald <[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* <http://www.imgur.com/> and include the link in your

> posting.

> > *****

> >

> > Possibly the damage is to the optical cement between the lens elements.

> I found epoxy to be very absorbtive and could be damaged during 2-photon

> imaging.

> >

> > Regards,

> > Glen MacDonald

> > Digital Microscopy Center

> > Box 357923

> > University of Washington

> > Seattle, WA 98195-7923 USA

> > (206) 616-4156

> > [hidden email]

> >

> >

> >

> >

> >

> >

> >

> >

> >> On May 27, 2016, at 8:03 AM, Nuno Moreno <[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* <http://www.imgur.com/> and include the link in your

> posting.

> >> *****

> >>

> >> Dear Craig

> >>

> >> I sent already a message directly to Joshua with a similar statement.

> The problem is however when the burning in not at the first lens but

> somewhere inside. In this case this means that the objective was not

> assembled in a proper clean environment and has dust or other particles

> inside. Actually here at the institute we were surprised on how often this

> happens from 2 different manufacturers. Maybe we were just unlucky. If that

> is the case I would ask for a replacement free of charge. I must confess

> however that in Joshua case it does not look like but the picture is not

> clear enough. I would advice you to bring your objective to a stereoscope,

> start to focus on the first back optical element and check whether this is

> superficial or not.

> >>

> >> Kind regards and good luck

> >> Nuno Moreno

> >>

> >>> On 27 May 2016, at 15:07, 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* <http://www.imgur.com/> and include the link in your

> posting.

> >>> *****

> >>>

> >>> I had a glance at your picture. The black spots look like laser burns,

> but

> >>> there is also a clear bubble or edge that looks suspiciously like oil

> also

> >>> visible in the picture. It's possible you had some oil contamination

> and

> >>> then it burned onto the glass. Most optics will handle a surprising

> amount

> >>> of laser power as long as they are extremely clean. The instant there

> is

> >>> any dust/grease the laser will burn the surface as the contamination

> >>> increases point absorption at the interface.

> >>>

> >>> Craig

> >>>

> >>>> On Fri, May 27, 2016 at 7:28 AM, Martin Wessendorf <[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* <http://www.imgur.com/> and include the link in your

> posting.

> >>>> *****

> >>>>

> >>>> Dear Dr. Vaughan--

> >>>>

> >>>> Could it be dirt and oil on the lens, rather than being burned and/or

> >>>> unglued?

> >>>>

> >>>> Martin Wessendorf

> >>>>

> >>>>

> >>>>

> >>>>

> >>>>> On 5/27/2016 2:58 AM, Joshua Vaughan 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* <http://www.imgur.com/> and include the link in
your

> posting.

> >>>>> *****

> >>>>>

> >>>>> 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

> >>>>

> >>>> --

> >>>> Martin Wessendorf, Ph.D. office: (612) 626-0145

> >>>> Assoc Prof, Dept Neuroscience lab: (612) 624-2991

> >>>> University of Minnesota Preferred FAX: (612) 624-8118

> >>>> 6-145 Jackson Hall, 321 Church St. SE Dept Fax: (612) 626-5009

> >>>> Minneapolis, MN55455 e-mail: [hidden email]

> >>>>

Best regards,

Alexander N. Asanov, Ph.D.
President, TIRF Labs
106 Grendon Place
Cary, NC 27519
Tel: 919-463-9545 Mobile: 919-903-4792

[hidden email] <mailto:[hidden email]>

www.tirf-labs.com <http://www.tirf-labs.com/> www.TIRFmicroscopy.com
<http://www.tirfmicroscopy.com/>

*From:*Martin Wessendorf [mailto:[hidden email]]
*Sent:* Monday, May 23, 2016 1:16 PM
*To:* Alexander Asanov
*Subject:* Re: Policy for commercial postings

Dear Dr. Asanov--

My apologies for taking so long to get back to you. Typically, people
use the list if they have a question or if they can provide the answer
to another person's question. (It's sometimes used for announcements as
well.) If you have a question about TIRFM, feel free to send to me and
if it's appropriate I'll post it for you.

Again, you may want to look back through the Archives to get a sense of
how the List is used.

Sincerely,

Martin Wessendorf

On 5/10/2016 10:44 PM, Alexander Asanov wrote:

Dear Dr. Wessendorf,

I would like to initiate a discussion about TIRFM geometries. The
Confocal community will benefit of the knowledge that will be shared
in this discussion. Would you approve such discussion? Without any
intent to sell anything?

Did you know that approximately 70% of your academic subscribers are
owners, partial owners, or have financial interest in commercial
entities operating in the field of microscopy? Do you have a
mechanism to detect such hidden interests?

Sincerely,

Alexander N. Asanov, Ph.D.
President, TIRF Labs
106 Grendon Place
Cary, NC 27519
Tel: 919-463-9545 Mobile: 919-903-4792

[hidden email] <mailto:[hidden email]>

www.tirf-labs.com <http://www.tirf-labs.com> www.TIRFmicroscopy.com
<http://www.tirfmicroscopy.com/>

*From:*Martin Wessendorf [mailto:[hidden email]]
*Sent:* Tuesday, May 10, 2016 10:59 PM
*To:* Alexander Asanov
*Subject:* Re: Policy for commercial postings

Dear Dr. Asanov--

I think we've said about all we can at this point. Please study the
Policy and the Archives to get a feel for how other representatives
of the private sector act. Again, for now, if you want to post
something, send it to me and I'll post it on your behalf.

Sincerely,

Martin Wessendorf

On 5/10/2016 3:53 PM, Alexander Asanov wrote:

Dear Dr. Wessendorf,

Be sure that my post is about science and technology, rather
than commerce. It appears that you have incorrect perception
that everything which originates in industrial settings has
commercial intent.

Confocal community would benefit tremendously of comparison
lgTIRF and pTIRF with objective-type TIRF. In fact, it is quite
obvious that it was terrible idea to use low light emission
channel to pipe high-intensity excitation light. Several
brilliant papers have been published in scientific journals
about poor quality of objective-type TIRF. However,
objective-TIRF is a die-hard misconception, which has received
millions of commercial dollars to deform the perception of TIRF
users. Read TIRF posts of your subscribers.

Affiliation of annoyed subscriber does not matter. He or she can
have indirect interests and motivations at subconscience.

While super-resolution and expansion microscopy and single
molecule detection become indispensable tools, the significance
of TIRF increases.

It appears that you failed to distinguish between science and
commerce. I feel strongly that it is too difficult if not
impossible for an industrial subscriber to contribute knowledge
value to the confocal forum under your moderation.

I agree with you only to your point that rules established by a
moderator should be complied with. No questions. I did not
intend to go over your rules. I reiterate my apologies.

However, I firmly disagree with your attempt to downsize the
significance of my TIRF posting to commercial intent. It appears
that regardless of the content and knowledge value, all posting
originated from industry will be considered as commercial. It is
sad method of perception.

All 2,000+ of confocal subscribers would benefit tremendously of
the knowledge about the advantages and disadvantages of lgTIRF
and pTIRF with objective TIRF.

I wish I would be wrong, because you state in your rules that
you appreciate the contribution from industrial players. Could
you point out to a single knowledge posting at your list from an
industrial player?

Sincerely,

Alexander N. Asanov, Ph.D.
President, TIRF Labs
106 Grendon Place
Cary, NC 27519
Tel: 919-463-9545 *www*.tirf-labs.com
<http://www.tirf-labs.com/>www.TIRFmicroscopy.com
<http://www.TIRFmicroscopy.com>
Mobile: 919-903-4792 [hidden email]
<mailto:[hidden email]>

*From:*Martin Wessendorf [mailto:[hidden email]]
*Sent:* Tuesday, May 10, 2016 12:04 PM
*To:* Alexander Asanov <[hidden email]>
<mailto:[hidden email]>
*Subject:* Policy for commercial postings

Dear Dr. Asanov--

I apologize for again bringing up an uncomfortable subject
again, but there were a couple things that I thought worth
mentioning:

1) I think your idea of reformatting the Policy was excellent
and I used it when I reposted the Policy today.

2) The rules of conduct on the List are important to some of
its members. Minutes after re-posting the Policy, I received
the following note. I've removed any identifiers but it came
from the marketing director of company involved in optics and
microscopy. --People who make a point of playing by the rules
are probably the most adamant about others playing by the rules.

Sincerely,

Martin Wessendorf
-----------------------------------

*Subject: *

Thank you

*Date: *

Tue, 10 May 2016 16:39:05 +0100

*To: *

Martin Wessendorf <[hidden email]> <mailto:[hidden email]>

I appreciate the post as I was quite annoyed with tirf-labs.

Thank you for all you do!

----------------------------------

--

Martin Wessendorf, Ph.D. office: (612) 626-0145

Assoc Prof, Dept Neuroscience lab: (612) 624-2991

University of Minnesota Preferred FAX: (612) 624-8118

6-145 Jackson Hall, 321 Church St. SE Dept Fax: (612) 626-5009

Minneapolis, MN 55455 e-mail:[hidden email] <mailto:[hidden email]>

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--

Martin Wessendorf, Ph.D. office: (612) 626-0145

Assoc Prof, Dept Neuroscience lab: (612) 624-2991

University of Minnesota Preferred FAX: (612) 624-8118

6-145 Jackson Hall, 321 Church St. SE Dept Fax: (612) 626-5009

Minneapolis, MN 55455 e-mail:[hidden email] <mailto:[hidden email]>

<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon>
Virus-free. www.avast.com
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