white light source for Yokogawa SD?

[Gary Yellen]

I am interested in the possibility of using a white light source (e.g. xenon arc lamp) with a spinning disk system. We are developing fluorescent biosensors based on various GFP derivatives, and the spectral flexibility of this approach over multiple lasers would be very helpful. It seems as though the Yokogawa system with the microlenses would have the best light throughput, but the input is adapted to a singlemode fiber from a laser. I have seen two publications describing this application (both done with pre-CSU-X1 models): The first (http://www.jstage.jst.go.jp/article/csf/33/1/133/_pdf) uses the output of a mercury lamp focused into a 1-mm multimode fiber attached to the normal light input port of the CSU. It is not clear how efficient or inefficient this is - i.e. how much of this large fiber core is seen by the CSU input optics. This was done with a CSU10, and I wonder if the new beam-shaping optics on the CSU-X1 would make this better or worse. The second (http://www.olympusconfocal.com/theory/noncoherentsources.html) describes the use of a collimating lens and mirror, introduced into the CSU at the location of the single excitation filter holder, to introduce light from a liquid light guide into the optical path of the CSU, apparently after the beam-shaping optics for the laser fiber. This approach requires a bit more fabrication, and it is not clear to me whether this would even be possible with the CSU-X1. It seems (both from reading these sources and from manufacturers' specs) that there should be plenty of light from a good xenon source. For instance, the 300W xenon source (Lambda LS from Sutter Instruments) is quoted as having ~500-700 mW of power in 25 nm width bands over the visible wavelength range, and this is at the end of a 3mm liquid light guide. I would be grateful for comments or suggestions about the feasibility of this approach, or the best way to accomplish it. Gary Yellen, Ph.D. Department of Neurobiology Harvard Medical School

[Cameron, Lisa]

Hello -

I saw your post on the confocal listserv and thought I would let you know that
our facility at Dana Farber has one of the new white light lasers (a
supercontinuum laser) on the market. Ours is on the Leica SP5 confocal, so it is
a scanning confocal and not the microlens based Yokogawa, but you are welcome to
try it out. Leica gets the white light laser from a company called Koheras. It
is delivered by a single fiber optic. I am fairly certain that they are using a
fiber optic and coupler from PointSource. I'm not sure whether you can purchase
a white light laser yourself directly from Koheras or any other company. Zeiss
is also now marketing a white light laser that they call "In Tune", but it will
most certainly be in conjunction with their laser scanning system, too. I found
a listing online that advertises that you can get a white light laser from
Koheras for around $20,000 at http://optics.org/cws/product/P000000270. I'm not
sure of a reasonable price for just a white light laser, but Leica charges
around $160,000 more if you add a white light laser to their scanning confocal.
If you do end up getting one of these supercontinuum lasers from somewhere, make
sure you get a service contract or some agreement for service. I have gone
through 3 white light lasers in 6 months with Leica and a 4th will be installed
in the next month. I'm not sure if they were just replacing the whole thing
because it was easier or whether we really needed a whole new one (I have a
feeling it's a combination of both). I have to say, as long as the white light
laser is working, the Leica SP5 system works great.

- Lisa
-------------------------
Lisa Cameron, Ph.D.
Director of Confocal and Light Microscopy
Dana Farber Cancer Institute
44 Binney St. JF 220B
Boston, MA 02115
617-582-8824


-----Original Message-----
From: Confocal Microscopy List on behalf of Gary Yellen
Sent: Sat 7/25/2009 10:33 AM
To: [hidden email]
Subject: [CONFOCALMICROSCOPY] white light source for Yokogawa SD?
 
I am interested in the possibility of using a white light source (e.g. xenon arc
lamp) with a spinning disk system. We are developing fluorescent biosensors
based on various GFP derivatives, and the spectral flexibility of this approach
over multiple lasers would be very helpful. It seems as though the Yokogawa
system with the microlenses would have the best light throughput, but the input
is adapted to a singlemode fiber from a laser. I have seen two publications
describing this application (both done with pre-CSU-X1 models): The first
(http://www.jstage.jst.go.jp/article/csf/33/1/133/_pdf) uses the output of a
mercury lamp focused into a 1-mm multimode fiber attached to the normal light
input port of the CSU. It is not clear how efficient or inefficient this is -
i.e. how much of this large fiber core is seen by the CSU input optics. This was
done with a CSU10, and I wonder if the new beam-shaping optics on the CSU-X1
would make this better or worse. The second
(http://www.olympusconfocal.com/theory/noncoherentsources.html) describes the
use of a collimating lens and mirror, introduced into the CSU at the location of
the single excitation filter holder, to introduce light from a liquid light
guide into the optical path of the CSU, apparently after the beam-shaping optics
for the laser fiber. This approach requires a bit more fabrication, and it is
not clear to me whether this would even be possible with the CSU-X1. It seems
(both from reading these sources and from manufacturers' specs) that there
should be plenty of light from a good xenon source. For instance, the 300W xenon
source (Lambda LS from Sutter Instruments) is quoted as having ~500-700 mW of
power in 25 nm width bands over the visible wavelength range, and this is at the
end of a 3mm liquid light guide. I would be grateful for comments or suggestions
about the feasibility of this approach, or the best way to accomplish it. Gary
Yellen, Ph.D. Department of Neurobiology Harvard Medical School



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[Alessandro Esposito]

Dear Lisa,
   I thought the SuperK by Koheras was more expensive. I do not know the
american market, but I though they cost in excess of 60kUSD, which is
reasonable because they could replace many lasers and it is a pulsed source
useful for FLIM as well.

Is the Keheras on the SP5 providing problems? I thought Keheras was
guaranteeing their lasers for 2khrs imaging with a careful maintenence plan to
minimize unplanned downtime periods.

The truth is that supercontinuum lasers are a new technology and we'll have
to wait some more years before they get an ideal commercial product. Still, if
you do not rely exclusevly on them, they are very interesting sources.

I am not sure that with an AOTF one would have enough power in combination
with a spinning disk confocal. May be using excitation filters and using broader
excitation bands would be fine.

Cheers,

Alessandro
University of Cambridge
www.quantitative-microscopy.org

[Cameron, Lisa]

I apologize - I did not mean for my previous email to go out to the whole list,
but was replying to the poster who first asked about a white light source for a
Yokogawa SD, who also happens to have his lab close by my facility. I guess I
forgot to delete the confocal listserv email address.

Leica service has been great - both rapid in response and in getting things
working. As I understand it, the problem has been due to a part failing inside
the white light laser housing. Leica has said they are increasing their quality
control for these parts that are not built by them. I think our situation has
just been unlucky. I was only warning the previous poster that if they ended up
getting a supercontinuum laser, that a service contract is highly recommended.

And, yes, it is true that the laser is guaranteed for 2k hrs. But I don't think
it is the actual laser itself that is failing. It is a failsafe measure that
turns off the laser, as I understand it.

As for the price - it is a ballpark figure of the additional cost of adding a
white light laser to an SP5 AOBS system, but I want to be clear that it is only
a very general price. I do not know what the current price of a laser from
Koheras is or how many different models they may have. I just saw a webpage
stating a price http://optics.org/cws/product/P000000270. Upon further review of
this website, it looks like it is an ad for Koheras from April 4, 2006 promoting
their product at the 2006 Photonics West conference, so the price may be out of
date. Also, I do not know exactly what product was being advertised on this
optics.org website (whether it is a similar product to what they supply to
Leica). Certainly the supercontinuum technology is very exciting and should be
able to replace many lasers.

And let me just say, I am still happy that we bought it.

As for whether a supercontinuum laser can be coupled to a Yokogawa, I agree that
the power output at a single wavelength through an AOTF may not be enough for a
Yokogawa. On the Leica system, we can turn on several laser lines close together
to get higher power, with obviously a broader excitation.

- Lisa

---------------------------------------
Lisa Cameron, Ph.D.
Director of Confocal and Light Microscopy
Dana Farber Cancer Institute


The information in this e-mail is intended only for the person to whom it is
addressed. If you believe this e-mail was sent to you in error and the e-mail
contains patient information, please contact the Partners Compliance HelpLine at
http://www.partners.org/complianceline . If the e-mail was sent to you in error
but does not contain patient information, please contact the sender and properly
dispose of the e-mail.