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We set up such a system recently using a xenon arc lamp modified for 
long-wavelength output from Sutter. At 740 nm we get about 50 mW out of 
a 10x objective in a 13 nm bandwidth.  I don't know if that qualifies as 
powerful or not, but for epi-fluorescence imaging, it's pretty bright.  
More details on my blog: http://nic.ucsf.edu/blog/?p=813

On a related note, does anyone have some numbers for the power densities 
required to saturate common fluorophores? I've been curious about using 
LED strobe illumination for very high speed imaging and I'm wondering 
how high you can push the power density before you saturate the dyes.

Kurt

On 11/22/2013 7:33 AM, Judy Trogadis wrote:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
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> *****
>
> Hi All
>
> This posting of a couple of weeks ago has suddenly become relevant for us.
>
> Does anyone know of a powerful continuous white light source in the 600-800nm range? Emphasis on the word 'powerful' because in most light sources there seems to be a steep drop in power above 650nm.
>
> Thank you,
> Judy
>
> Judy Trogadis
> Bio-Imaging Coordinator
> Keenan Research Centre, St. Michael's
> 209 Victoria Street
> Toronto M5B 1T8, Canada
> office: 416-864-6060 ext. 77612
> imaging facility:           ext. 77434
> cell:        416-254-9330
> [log in to unmask]
>
>
>
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[log in to unmask]] On Behalf Of Ben Freiberg
> Sent: Thursday, November 07, 2013 10:59 PM
> To: [log in to unmask]
> Subject: Re: Brightness difference Hg vs LED
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
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>
> All,
>
> Having been involved in the lighting industry from a commercial standpoint I
> wanted to respond to this thread in an unbiased and independent experienced
> voice.
>
> As has been previously mentioned, there are many areas of the spectrum in
> which solid-state solutions have surpassed HBO in intensity at the sample
> plane.  I completely agree with the assessments that there are many
> components that go into building an illuminator and therefore many sources
> of light loss in the systems on the market.  Key to any measurement of power
> is how much light is delivered to the sample, so if anyone does take up the
> offer to compare light sources, measurement of mW//cm^2 at the sample plane
> will provide the best indication of the total performance of a light source
> on a microscope.  That being said, one must make sure that the excitation
> filters used with solid-state sources are matched to the peak of the source
> and not simply use off the shelf filters and expect them to perform optimally.
>
> There has been mention in this thread of the gaps produced when using
> multiple sources and combining them into a shared collimated beam.  As has
> been stated, in general, increasing the number of input sources decreases
> the overall throughput of light in the system as source combining optics can
> be lossy and will cut the overall intensity of any single source that could
> be coupled to the microscope.  One solution that has not been mentioned in
> this thread is the 120-LED from Lumen Dynamics.  The 120 LED overcomes the
> limits of combining multiple sources by using a high intensity white LED
> source.  This product, according to the LDGI website, covers wavelengths
> from 370nm all the way out to 700+ nm with reasonable intensity.  While HBO
> may be brighter at some wavelengths versus the 120-LED, rarely are these
> sources, HBO or solid-state, used at max power especially in live cell
> applications.
>
> I would suggest that the 120-LED be included in whatever tests come from
> this thread as it is a unique product from the standpoint of how the white
> light is generated for fluorescence applications versus the other solutions
> on the market that combine many sources.
>
> As for the overall performance of all solid state products mentioned thus
> far in this thread, one should consider the following: every mid to high end
> solid state source produces multiple times more power than 175W xenon at the
> sample plane at all wavelengths greater than 360nm and all the way out to
> the NIR.  If anyone has experience using xenon as their primary source, I
> hope this puts the current state of solid-state illuminator intensity into
> perspective.   Bottom line is for most applications, the benefits in cost of
> ownership, stability and overall function have the solid-state solutions
> greatly out-perform their HBO counterparts with an additional benefit being
> that solid-state sources are a green solution and they eliminate the threat
> of mercury contamination due to improper disposal or explosion of mercury
> burners.
>
> Ben
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On Tue, 5 Nov 2013 12:56:42 -0500, Philip Oshel <[log in to unmask]> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> All,
>>
>> I had this question put to me by a new faculty member, and don't have a
>> ready answer:
>> "Is there a ballpark percentage for how much less bright an LED vs a
>> standard mercury lamp light?"
>> This is for regular epifluorescence, not confocal.
>>
>> This is in the realm of arm-waving over a picture of beer (a good, dark
>> stout), ignoring brands, how old the Hg bulb is, ex/em cubes, which part
>> of the spectrum is used, and all that. Personally, I'd think the answer
>> is more like, "Doesn't matter, the dimmer system is still too bright to
>> use all the available light and not damage the specimen." But ... ?
>>
>> Phil
>> --
>> Philip Oshel
>> Microscopy Facility Supervisor
>> Biology Department
>> 024C Brooks Hall
>> Central Michigan University
>> Mt. Pleasant, MI 48859
>> (989) 774-3576
>