instrument to measure laser intensity on slide

[Martin Schattat]

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Hallo List members,

we are imaging plant cells with a Zeiss780 and are wondering how much laser light we actually expose our cells too. I was told that there are instruments with which it is possible to measure the laser intensity at the opening of the microscope lens. It would be nice if any one could share experience with such measurements.

thanks in advance,

Martin


-------------------------------------------------------------------
Dr. Martin Schattat
Martin-Luther-Universität Halle-Wittenberg
Institutsbereich Pflanzenphysiologie
Weinbergweg 10, 06120 Halle (Saale), Germany

Tel.:     [phone]
Email: [hidden email]

[Martin Seem]

*****
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 Martin,

are you thinking of a laser power meter? If so, there are multiple ones
available that will allow you measure laser line output at the stage.
However if you specifically want to measure output from high NA
immersion objectives things become more complicated. You might find that
this thread from March 2013 contains some useful information.

http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=14761

Martin Seem



On 04.07.2014 11:00, Martin Schattat 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.
> *****
>
> Hallo List members,
>
> we are imaging plant cells with a Zeiss780 and are wondering how much laser light we actually expose our cells too. I was told that there are instruments with which it is possible to measure the laser intensity at the opening of the microscope lens. It would be nice if any one could share experience with such measurements.
>
> thanks in advance,
>
> Martin
>
>
> -------------------------------------------------------------------
> Dr. Martin Schattat
> Martin-Luther-Universität Halle-Wittenberg
> Institutsbereich Pflanzenphysiologie
> Weinbergweg 10, 06120 Halle (Saale), Germany
>
> Tel.:     [phone]
> Email: [hidden email]

[Martin Schattat]

*****
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.
*****

Hello List,

thanks for the fast replies, I am always fascinated how fast one get reactions :) pascal pointed thorlabs out to me and I think this was the company I was told about. The Microscope Photodiode Power Sensor S170C sounds good and seems to also work with immersion lenses. Does anyone has experience with this kind of sensor?

thanks also for the other recommendations!

Martin
-------------------------------------------------------------------
Dr. Martin Schattat
Martin-Luther-Universität Halle-Wittenberg
Institutsbereich Pflanzenphysiologie
Weinbergweg 10, 06120 Halle (Saale), Germany

Tel.:     [phone]
Email: [hidden email]





Am 04.07.2014 um 13:41 schrieb Martin Seem <[hidden email]>:

> *****
> 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 Martin,
>
> are you thinking of a laser power meter? If so, there are multiple ones available that will allow you measure laser line output at the stage. However if you specifically want to measure output from high NA immersion objectives things become more complicated. You might find that this thread from March 2013 contains some useful information.
>
> http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=14761
>
> Martin Seem
>
>
>
> On 04.07.2014 11:00, Martin Schattat 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.
>> *****
>>
>> Hallo List members,
>>
>> we are imaging plant cells with a Zeiss780 and are wondering how much laser light we actually expose our cells too. I was told that there are instruments with which it is possible to measure the laser intensity at the opening of the microscope lens. It would be nice if any one could share experience with such measurements.
>>
>> thanks in advance,
>>
>> Martin
>>
>>
>> -------------------------------------------------------------------
>> Dr. Martin Schattat
>> Martin-Luther-Universität Halle-Wittenberg
>> Institutsbereich Pflanzenphysiologie
>> Weinbergweg 10, 06120 Halle (Saale), Germany
>>
>> Tel.:     [phone]
>> Email: [hidden email]

[Zdenek Svindrych]

*****
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 Martin,



It has been discussed in detail some time ago. The bottom line is: it's not
trivial. 

Thorlabs does not say anything about angular dependence of the photodiode,
but it's substantial. You may search for specs sheets of Ophir power
sensors. If you use large part of the back focal aperture of your objective
for illumination (that's always the case for a confocal microscope), the
beam will be very divergent in the sample space for high NA immersion lenses
and your measurement will be wrong (you'll measure too low a value).

I always measure the power with the objective removed, the light outside the
back focal aperture blocked, and assuming some 25 percent loss in the
objective (can be measured to some accuracy with low NA illumination). It's
just a rough estimate anyway...




Regards,

zdenek svindrych






---------- Původní zpráva ----------
Od: Martin Schattat <[hidden email]>
Komu: [hidden email]
Datum: 4. 7. 2014 13:54:22
Předmět: Re: instrument to measure laser intensity on slide

"*****
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.
*****

Hello List,

thanks for the fast replies, I am always fascinated how fast one get
reactions :) pascal pointed thorlabs out to me and I think this was the
company I was told about. The Microscope Photodiode Power Sensor S170C
sounds good and seems to also work with immersion lenses. Does anyone has
experience with this kind of sensor?

thanks also for the other recommendations!

Martin
-------------------------------------------------------------------
Dr. Martin Schattat
Martin-Luther-Universität Halle-Wittenberg
Institutsbereich Pflanzenphysiologie
Weinbergweg 10, 06120 Halle (Saale), Germany

Tel.: [phone]
Email: [hidden email]





Am 04.07.2014 um 13:41 schrieb Martin Seem <[hidden email]>:

> *****
> 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 Martin,
>
> are you thinking of a laser power meter? If so, there are multiple ones
available that will allow you measure laser line output at the stage.
However if you specifically want to measure output from high NA immersion
objectives things become more complicated. You might find that this thread
from March 2013 contains some useful information.
>
> http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=
14761

>
> Martin Seem
>
>
>
> On 04.07.2014 11:00, Martin Schattat 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.
>> *****
>>
>> Hallo List members,
>>
>> we are imaging plant cells with a Zeiss780 and are wondering how much

laser light we actually expose our cells too. I was told that there are
instruments with which it is possible to measure the laser intensity at the
opening of the microscope lens. It would be nice if any one could share
experience with such measurements.

>>
>> thanks in advance,
>>
>> Martin
>>
>>
>> -------------------------------------------------------------------
>> Dr. Martin Schattat
>> Martin-Luther-Universität Halle-Wittenberg
>> Institutsbereich Pflanzenphysiologie
>> Weinbergweg 10, 06120 Halle (Saale), Germany
>>
>> Tel.: [phone]
>> Email: [hidden email]"

[Craig Brideau]

*****
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.
*****

I helped Thorlabs design the S170C slide power sensor. It has an
index-matching layer between the protective glass window and the photodiode
to help keep the light from reflecting off the surface of the sensor. It's
one of the first (*the* first to my knowledge) sensor to address this
problem. I use it myself to measure power from high NA oil and water
lenses. I recommend isopropanol at a high purity with lens tissues for
cleaning oil off the sensor window after use.

Craig Brideau


On Fri, Jul 4, 2014 at 7:07 AM, Zdenek Svindrych <[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 Martin,
>
>
>
> It has been discussed in detail some time ago. The bottom line is: it's not
> trivial.
>
> Thorlabs does not say anything about angular dependence of the photodiode,
> but it's substantial. You may search for specs sheets of Ophir power
> sensors. If you use large part of the back focal aperture of your objective
> for illumination (that's always the case for a confocal microscope), the
> beam will be very divergent in the sample space for high NA immersion
> lenses
> and your measurement will be wrong (you'll measure too low a value).
>
> I always measure the power with the objective removed, the light outside
> the
> back focal aperture blocked, and assuming some 25 percent loss in the
> objective (can be measured to some accuracy with low NA illumination). It's
> just a rough estimate anyway...
>
>
>
>
> Regards,
>
> zdenek svindrych
>
>
>
>
>
>
> ---------- Původní zpráva ----------
> Od: Martin Schattat <[hidden email]>
> Komu: [hidden email]
> Datum: 4. 7. 2014 13:54:22
> Předmět: Re: instrument to measure laser intensity on slide
>
> "*****
> 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.
> *****
>
> Hello List,
>
> thanks for the fast replies, I am always fascinated how fast one get
> reactions :) pascal pointed thorlabs out to me and I think this was the
> company I was told about. The Microscope Photodiode Power Sensor S170C
> sounds good and seems to also work with immersion lenses. Does anyone has
> experience with this kind of sensor?
>
> thanks also for the other recommendations!
>
> Martin
> -------------------------------------------------------------------
> Dr. Martin Schattat
> Martin-Luther-Universität Halle-Wittenberg
> Institutsbereich Pflanzenphysiologie
> Weinbergweg 10, 06120 Halle (Saale), Germany
>
> Tel.: [phone]
> Email: [hidden email]
>
>
>
>
>
> Am 04.07.2014 um 13:41 schrieb Martin Seem <[hidden email]>:
>
> > *****
> > 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 Martin,
> >
> > are you thinking of a laser power meter? If so, there are multiple ones
> available that will allow you measure laser line output at the stage.
> However if you specifically want to measure output from high NA immersion
> objectives things become more complicated. You might find that this thread
> from March 2013 contains some useful information.
> >
> > http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=
> 14761
> >
> > Martin Seem
> >
> >
> >
> > On 04.07.2014 11:00, Martin Schattat 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.
> >> *****
> >>
> >> Hallo List members,
> >>
> >> we are imaging plant cells with a Zeiss780 and are wondering how much
> laser light we actually expose our cells too. I was told that there are
> instruments with which it is possible to measure the laser intensity at the
> opening of the microscope lens. It would be nice if any one could share
> experience with such measurements.
> >>
> >> thanks in advance,
> >>
> >> Martin
> >>
> >>
> >> -------------------------------------------------------------------
> >> Dr. Martin Schattat
> >> Martin-Luther-Universität Halle-Wittenberg
> >> Institutsbereich Pflanzenphysiologie
> >> Weinbergweg 10, 06120 Halle (Saale), Germany
> >>
> >> Tel.: [phone]
> >> Email: [hidden email]"
>

[Zdenek Svindrych]

*****
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.
*****

That sounds good. Then the Fresnel losses should not be such a problem (at
least for nonpolarised and/or axially symmetric illumination). If Thorlabs
provided the angular dependence curves (I've failed to find it), this would
shed some more light into the matter. Though, I know it's complicated by the
polarisation and wavelength dependence.
Also, users should always exercise caution when measuring in the objective
focus, as the max power density (20W/cm^2, probably very conservative) can
easily be exceeded.

Best, Zdenek Svindrych



---------- Původní zpráva ----------
Od: Craig Brideau <[hidden email]>
Komu: [hidden email]
Datum: 6. 7. 2014 1:04:06
Předmět: Re: instrument to measure laser intensity on slide

"*****
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.
*****

I helped Thorlabs design the S170C slide power sensor. It has an
index-matching layer between the protective glass window and the photodiode
to help keep the light from reflecting off the surface of the sensor. It's
one of the first (*the* first to my knowledge) sensor to address this
problem. I use it myself to measure power from high NA oil and water
lenses. I recommend isopropanol at a high purity with lens tissues for
cleaning oil off the sensor window after use.

Craig Brideau


On Fri, Jul 4, 2014 at 7:07 AM, Zdenek Svindrych <[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 Martin,
>
>
>
> It has been discussed in detail some time ago. The bottom line is: it's

not
> trivial.
>
> Thorlabs does not say anything about angular dependence of the photodiode,
> but it's substantial. You may search for specs sheets of Ophir power
> sensors. If you use large part of the back focal aperture of your
objective
> for illumination (that's always the case for a confocal microscope), the
> beam will be very divergent in the sample space for high NA immersion
> lenses
> and your measurement will be wrong (you'll measure too low a value).
>
> I always measure the power with the objective removed, the light outside
> the
> back focal aperture blocked, and assuming some 25 percent loss in the
> objective (can be measured to some accuracy with low NA illumination). It'
s

> just a rough estimate anyway...
>
>
>
>
> Regards,
>
> zdenek svindrych
>
>
>
>
>
>
> ---------- Původní zpráva ----------
> Od: Martin Schattat <[hidden email]>
> Komu: [hidden email]
> Datum: 4. 7. 2014 13:54:22
> Předmět: Re: instrument to measure laser intensity on slide
>
> "*****
> 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.
> *****
>
> Hello List,
>
> thanks for the fast replies, I am always fascinated how fast one get
> reactions :) pascal pointed thorlabs out to me and I think this was the
> company I was told about. The Microscope Photodiode Power Sensor S170C
> sounds good and seems to also work with immersion lenses. Does anyone has
> experience with this kind of sensor?
>
> thanks also for the other recommendations!
>
> Martin
> -------------------------------------------------------------------
> Dr. Martin Schattat
> Martin-Luther-Universität Halle-Wittenberg
> Institutsbereich Pflanzenphysiologie
> Weinbergweg 10, 06120 Halle (Saale), Germany
>
> Tel.: [phone]
> Email: [hidden email]
>
>
>
>
>
> Am 04.07.2014 um 13:41 schrieb Martin Seem <[hidden email]>:
>
> > *****
> > 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 Martin,
> >
> > are you thinking of a laser power meter? If so, there are multiple ones
> available that will allow you measure laser line output at the stage.
> However if you specifically want to measure output from high NA immersion
> objectives things become more complicated. You might find that this thread
> from March 2013 contains some useful information.
> >
> > http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=
> 14761
> >
> > Martin Seem
> >
> >
> >
> > On 04.07.2014 11:00, Martin Schattat 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.
> >> *****
> >>
> >> Hallo List members,
> >>
> >> we are imaging plant cells with a Zeiss780 and are wondering how much
> laser light we actually expose our cells too. I was told that there are
> instruments with which it is possible to measure the laser intensity at

the

> opening of the microscope lens. It would be nice if any one could share
> experience with such measurements.
> >>
> >> thanks in advance,
> >>
> >> Martin
> >>
> >>
> >> -------------------------------------------------------------------
> >> Dr. Martin Schattat
> >> Martin-Luther-Universität Halle-Wittenberg
> >> Institutsbereich Pflanzenphysiologie
> >> Weinbergweg 10, 06120 Halle (Saale), Germany
> >>
> >> Tel.: [phone]
> >> Email: [hidden email]"
>"

[Martin Schattat]

*****
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 guys,

thanks for the comments on the S170C slide power sensor. We use normally 40x air objectives and a CLSM for our movies and this will as it seems not cause that much problems. However it is good to know that the sensor also gives a good estimate for higher NA objectives. Thanks again,

Martin

-------------------------------------------------------------------
Dr. Martin Schattat
Martin-Luther-Universität Halle-Wittenberg
Institutsbereich Pflanzenphysiologie
Weinbergweg 10, 06120 Halle (Saale), Germany

Tel.:     [phone]
Email: [hidden email]

On Jul 7, 2014, at 7:58 AM, Zdenek Svindrych <[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.
> *****
>
> That sounds good. Then the Fresnel losses should not be such a problem (at
> least for nonpolarised and/or axially symmetric illumination). If Thorlabs
> provided the angular dependence curves (I've failed to find it), this would
> shed some more light into the matter. Though, I know it's complicated by the
> polarisation and wavelength dependence.
> Also, users should always exercise caution when measuring in the objective
> focus, as the max power density (20W/cm^2, probably very conservative) can
> easily be exceeded.
>
> Best, Zdenek Svindrych
>
>
>
> ---------- Původní zpráva ----------
> Od: Craig Brideau <[hidden email]>
> Komu: [hidden email]
> Datum: 6. 7. 2014 1:04:06
> Předmět: Re: instrument to measure laser intensity on slide
>
> "*****
> 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.
> *****
>
> I helped Thorlabs design the S170C slide power sensor. It has an
> index-matching layer between the protective glass window and the photodiode
> to help keep the light from reflecting off the surface of the sensor. It's
> one of the first (*the* first to my knowledge) sensor to address this
> problem. I use it myself to measure power from high NA oil and water
> lenses. I recommend isopropanol at a high purity with lens tissues for
> cleaning oil off the sensor window after use.
>
> Craig Brideau
>
>
> On Fri, Jul 4, 2014 at 7:07 AM, Zdenek Svindrych <[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 Martin,
>>
>>
>>
>> It has been discussed in detail some time ago. The bottom line is: it's
> not
>> trivial.
>>
>> Thorlabs does not say anything about angular dependence of the photodiode,
>> but it's substantial. You may search for specs sheets of Ophir power
>> sensors. If you use large part of the back focal aperture of your
> objective
>> for illumination (that's always the case for a confocal microscope), the
>> beam will be very divergent in the sample space for high NA immersion
>> lenses
>> and your measurement will be wrong (you'll measure too low a value).
>>
>> I always measure the power with the objective removed, the light outside
>> the
>> back focal aperture blocked, and assuming some 25 percent loss in the
>> objective (can be measured to some accuracy with low NA illumination). It'
> s
>> just a rough estimate anyway...
>>
>>
>>
>>
>> Regards,
>>
>> zdenek svindrych
>>
>>
>>
>>
>>
>>
>> ---------- Původní zpráva ----------
>> Od: Martin Schattat <[hidden email]>
>> Komu: [hidden email]
>> Datum: 4. 7. 2014 13:54:22
>> Předmět: Re: instrument to measure laser intensity on slide
>>
>> "*****
>> 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.
>> *****
>>
>> Hello List,
>>
>> thanks for the fast replies, I am always fascinated how fast one get
>> reactions :) pascal pointed thorlabs out to me and I think this was the
>> company I was told about. The Microscope Photodiode Power Sensor S170C
>> sounds good and seems to also work with immersion lenses. Does anyone has
>> experience with this kind of sensor?
>>
>> thanks also for the other recommendations!
>>
>> Martin
>> -------------------------------------------------------------------
>> Dr. Martin Schattat
>> Martin-Luther-Universität Halle-Wittenberg
>> Institutsbereich Pflanzenphysiologie
>> Weinbergweg 10, 06120 Halle (Saale), Germany
>>
>> Tel.: [phone]
>> Email: [hidden email]
>>
>>
>>
>>
>>
>> Am 04.07.2014 um 13:41 schrieb Martin Seem <[hidden email]>:
>>
>>> *****
>>> 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 Martin,
>>>
>>> are you thinking of a laser power meter? If so, there are multiple ones
>> available that will allow you measure laser line output at the stage.
>> However if you specifically want to measure output from high NA immersion
>> objectives things become more complicated. You might find that this thread
>> from March 2013 contains some useful information.
>>>
>>> http://lists.umn.edu/cgi-bin/wa?A2=ind1303&L=confocalmicroscopy&D=0&P=
>> 14761
>>>
>>> Martin Seem
>>>
>>>
>>>
>>> On 04.07.2014 11:00, Martin Schattat 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.
>>>> *****
>>>>
>>>> Hallo List members,
>>>>
>>>> we are imaging plant cells with a Zeiss780 and are wondering how much
>> laser light we actually expose our cells too. I was told that there are
>> instruments with which it is possible to measure the laser intensity at
> the
>> opening of the microscope lens. It would be nice if any one could share
>> experience with such measurements.
>>>>
>>>> thanks in advance,
>>>>
>>>> Martin
>>>>
>>>>
>>>> -------------------------------------------------------------------
>>>> Dr. Martin Schattat
>>>> Martin-Luther-Universität Halle-Wittenberg
>>>> Institutsbereich Pflanzenphysiologie
>>>> Weinbergweg 10, 06120 Halle (Saale), Germany
>>>>
>>>> Tel.: [phone]
>>>> Email: [hidden email]"
>> "