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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy ***** Dear All, Immersion lens, especially high NA ones: Although not simple to setup, the most accurate way to measure transmittance/power is to use two objectives focused on a coverslip sandwich. The position in XY&Z can be tweaked to give the maximum power. Infinity corrected lens this is easier. I would be happy to provide more details off line. Happy imaging Rich Richard Cole Research Scientist V Director: Advanced Light Microscopy Core Unit Wadsworth Center Research Assistant Professor Dept. of Biomedical Sciences School of Public Health State University of New York P.O. Box 509 Albany N.Y. 12201-0509 518-474-7048 Phone 518-474-4430 Fax Email <mailto:[hidden email]> [hidden email] Website <http://www.wadsworth.org/cores/alm/index.htm> www.wadsworth.org/cores/alm/index.htm |
John Oreopoulos |
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy ***** Richard, that sounds like an interesting protocol. I'd like to learn about it. John Oreopoulos On 2013-03-13, at 9:41 AM, Richard Cole <[hidden email]> wrote: > ***** > To join, leave or search the confocal microscopy listserv, go to: > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy > ***** > > Dear All, > > > > Immersion lens, especially high NA ones: Although not simple to setup, the > most accurate way to measure transmittance/power is to use two objectives > focused on a coverslip sandwich. The position in XY&Z can be tweaked to > give the maximum power. Infinity corrected lens this is easier. I would be > happy to provide more details off line. > > > > Happy imaging > > > > Rich > > > > Richard Cole > Research Scientist V > Director: Advanced Light Microscopy Core Unit > Wadsworth Center > > > > Research Assistant Professor > Dept. of Biomedical Sciences > School of Public Health State University of New York > > > P.O. Box 509 Albany N.Y. 12201-0509 > 518-474-7048 Phone > 518-474-4430 Fax > > > > Email <mailto:[hidden email]> [hidden email] > > Website <http://www.wadsworth.org/cores/alm/index.htm> > www.wadsworth.org/cores/alm/index.htm > > > > > > |
James Jonkman |
In reply to this post by Richard Cole
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To join, leave or search the confocal microscopy listserv, go to: http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy ***** Hi, Martin. Nearly any of these power meters will do, but I agree that these measurements should be limited to dry objectives, leaving you to estimate the transmission of the high-NA objectives. Your application might be different than mine, but for me my main concern was laser instabilities on many of our confocals - it turned out to be more common than i thought, and i and my users were oblivious to thes problems until I started measuring it. I'm less interested in the absolute power at the sample for the high-NA lenses, and it's just too difficult to measure even if one of my users wanted to know it, so I just help them to estimate it. As per the best one to buy, my vote would be for the X-Cite XR2100 with sensor XP750, which seems to be the only power meter designed specifically for microscopy. It may seem like a small point, but having the sensor in the shape of a microscope slide makes it just that much easier to mount on the scopes. For the inverted scopes (and most of mine are inverted) I like that they have a target on the back of the sensor that i can aim my brightfield lamp at, so i know i'm in the middle of the objective. Also, for my widefield scopes, it has an extra sensor built into the power meter controller itself that lets me plug in my liquid light guides (X-Cite, Zeiss HXP, etc.) and measure the power of those lamps directly and very quickly. And i like that i can store my favourite wavelengths that correspond to my laser lines - makes it faster to switch between them. I have 2 other power meters (Coherent, Thorlabs), but i only use the X-Cite now. I must make a small disclaimer, though. Lumen Dynamics is just down the road from me, so they had me test-drive the power meter and wanted me to write an app note. I couldn't believe how many of my lasers were all over the place, once i started measuring them! When i saw this, i gladly bought the power meter (they gave me a 25% discount for my efforts with the app note, so hence the small financial disclaimer). Actually, i operate 2 sites and i just bought a second one so i'm putting my money where my mouth is. I don't have a good sense of how the X-Cite compares price-wise to other power meters, but for microscopists I think this one makes a lot of sense. Cheers, James |
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