Pulse broadening in multiphoton micoscopes

[Andreas Bruckbauer]

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope?

[Mayandi Sivaguru]

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use. These measurements are typically done by Application Scientists of the microscope vendors using the lasers either from Spectra or Coherent. Perhaps you can directly contact the head of applications of respective scope manufacturer that whether they have ever measured these peak widths directly on the objectives (air, oil and water immersions) using autocorrelators and so on. For example, you can contact Renee Hessling, Head of Applications, Carl Zeiss, Jena for such data from Zeiss ([hidden email]).
Shiv
 

At 12:25 PM 9/26/2008, you wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope? 

Mayandi Sivaguru, PhD, PhD
Microscopy Facility Manager
8, Institute for Genomic Biology
University of Illinois at Urbana-Champaign
1206 West Gregory Dr.
Urbana, IL 61801 USA

Office: 217.333.1214
Fax: [phone]
[hidden email]
http://core.igb.uiuc.edu

[Periasamy, Ammasi (ap3t)]

I do not expect any company can provide these details and its involved work. I know Dr. Warren Zipfel, David Wokosin and others measured these parameters. You can visit the web site given below or talk to Warren

http://www.drbio.cornell.edu/personnel/wrz2.html

Hope this helps

Ammasi

 

 

Ammasi Periasamy, Ph.D.

Director, Keck Center for Cellular Imaging (KCCI)

Professor of Biology and Biomedical Engineering

Biology, Gilmer Hall (064), McCormick Rd

University of Virginia

Charlottesville, VA 22904

Voice: 434-243-7602 (Office); 982-4869 (lab)

Fax:[phone]; Email:[hidden email]

http//:www.kcci.virginia.edu

************************

Workshop on FRET Microscopy, March 3-7, 2009

http://www.kcci.virginia.edu/workshop/workshop2009/index.php

 *************************

 

From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Mayandi Sivaguru
Sent: Friday, September 26, 2008 3:11 PM
To: [hidden email]
Subject: Re: Pulse broadening in multiphoton micoscopes

 

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use. These measurements are typically done by Application Scientists of the microscope vendors using the lasers either from Spectra or Coherent. Perhaps you can directly contact the head of applications of respective scope manufacturer that whether they have ever measured these peak widths directly on the objectives (air, oil and water immersions) using autocorrelators and so on. For example, you can contact Renee Hessling, Head of Applications, Carl Zeiss, Jena for such data from Zeiss ([hidden email]).
Shiv
 

At 12:25 PM 9/26/2008, you wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope? 

Mayandi Sivaguru, PhD, PhD
Microscopy Facility Manager
8, Institute for Genomic Biology
University of Illinois at Urbana-Champaign
1206 West Gregory Dr.
Urbana, IL 61801 USA

Office: 217.333.1214
Fax: [phone]
[hidden email]
http://core.igb.uiuc.edu

[Alison J. North]

The Rockefeller University is seeking a qualified and motivated
full-time microscopist for its expanding Bio-Imaging Resource Center.
The new Research Support Specialist will assist in advising and training
users in all areas of optical microscopy, including microscope set-up,
experimental design, sample preparation and data evaluation. The
Specialist will also perform trouble-shooting, microscope maintenance
and miscellaneous laboratory maintenance and job-related duties as
required and will report to the Director of the Center.  Collaborative
studies with RU researchers will also be encouraged for motivated
individuals.

The Bio-Imaging Resource Center is used by around 65 of the 75
laboratories at RU and we enjoy strong support within the University.
Equipment in the center currently includes a new Olympus upright
multiphoton system, a Zeiss LSM 510 inverted multiphoton system, two
Zeiss LSM 510 confocal microscopes (one with META detector), two
DeltaVision image restoration microscopes (including lasers for FRAP and
photoactivation), a Yokogawa-type spinning disk confocal microscope
fitted with the Photonics Instruments Digital Mosaic system for
FRAP/Photoactivation, an MMI laser microdissection system, and various
widefield fluorescence microscopes.  In 2008, we will add a multi-line
TIRF system with FLIM and photobleaching/photoactivation capabilities.

Requirements include a Master’s degree or Ph.D. in biology or a related
field and a minimum of two years of experience in advanced fluorescence
microscopy, preferably involving live cell imaging, plus experience with
sample preparation and image analysis.  Must have excellent
interpersonal and communication skills, an enthusiastic approach towards
new techniques, motivation to maintain a broad knowledge of
state-of-the-art imaging technology and the flexibility to interact with
a diverse group of researchers.  Strong organizational and multi-tasking
skills are also essential.

The Rockefeller University is located on a beautiful campus on
Manhattan's Upper East Side and offers an excellent benefits package and
a competitive salary.

To apply for this position, please visit the URL below and apply to job
code IRC5422 with a resume/CV and cover letter:

http://www.rockefeller.edu/hr/jobs.php

Questions about the application process or employment should be directed
to: [hidden email]
For specific technical questions about the BIRC’s instrumentation or
services, please feel free to contact Dr. Alison North, the Director of
the BIRC, at: [hidden email]


--
Alison J. North, Ph.D.,
Research Assistant Professor and
Director of the Bio-Imaging Resource Center,
The Rockefeller University,
1230 York Avenue,
New York,
NY 10065.
Tel: office ++ 212 327 7488
Tel: lab     ++ 212 327 7486
Fax:         ++ 212 327 7489

[Adrian Smith-6]

On 27/09/2008, at 5:10 AM, Mayandi Sivaguru wrote:

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use.

But that does not stop the laser manufacturers from using such concepts in the their sales pitch... which, (given I had exactly the same question about 2 years ago and never got a completely straight answer) is where I suspect the original poster is coming from :)

Regards,

Adrian

[Christian Soeller]

I believe this topic came up before in one guise or another. I searched
the archives

  http://lists.umn.edu/cgi-bin/wa?A0=CONFOCALMICROSCOPY

with the strings "chirp" or "pulse broadening" and got a number of hits.
One of those contains reference to a paper by us on the question.

My personal bottom line: with moderately long pulses (~120 fs) this does
not tend to be much of an issue. If you go to short pulses (why?) and
need extreme penetration depth you *might* consider it. The archived
messages talk about prechirping setups.

HTH

Christian


Andreas Bruckbauer wrote:
> Short pulses out of an IR laser broaden considerably when travelling through
> dispersive medium, e.g. glass lenses and acoustic optic modulator of a
> multi-photon microscope. It is often claimed that shorter pulses broaden
> more than longer ones. Does anybody know good literature on this? You can
> compensate for this by negative prechirp, would the small difference in
> initial pulse width between the Spectra Physics and Coherent lasers have an
> effect after prechirp and passing through the microscope?  
>  

[Warren Zipfel]

The listserve rejected my PDF.  It just had typical dispersion data for a couple of "typical" MPM configs. If anyone wants it, email me.

At 04:03 PM 9/26/2008, you wrote:

I do not expect any company can provide these details and its involved work. I know Dr. Warren Zipfel, David Wokosin and others measured these parameters. You can visit the web site given below or talk to Warren
http://www.drbio.cornell.edu/personnel/wrz2.html
Hope this helps
Ammasi
 
 
Ammasi Periasamy, Ph.D.
Director, Keck Center for Cellular Imaging (KCCI)
Professor of Biology and Biomedical Engineering
Biology, Gilmer Hall (064), McCormick Rd
University of Virginia
Charlottesville, VA 22904
Voice: 434-243-7602 (Office); 982-4869 (lab)
Fax:[phone]; Email:[hidden email]
http//:www.kcci.virginia.edu
************************
Workshop on FRET Microscopy, March 3-7, 2009
http://www.kcci.virginia.edu/workshop/workshop2009/index.php
 *************************
 
From: Confocal Microscopy List [[hidden email]] On Behalf Of Mayandi Sivaguru
Sent: Friday, September 26, 2008 3:11 PM
To: [hidden email]
Subject: Re: Pulse broadening in multiphoton micoscopes
 

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use. These measurements are typically done by Application Scientists of the microscope vendors using the lasers either from Spectra or Coherent. Perhaps you can directly contact the head of applications of respective scope manufacturer that whether they have ever measured these peak widths directly on the objectives (air, oil and water immersions) using autocorrelators and so on. For example, you can contact Renee Hessling, Head of Applications, Carl Zeiss, Jena for such data from Zeiss ([hidden email]).
Shiv
 

At 12:25 PM 9/26/2008, you wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope? 

Mayandi Sivaguru, PhD, PhD
Microscopy Facility Manager
8, Institute for Genomic Biology
University of Illinois at Urbana-Champaign
1206 West Gregory Dr.
Urbana, IL 61801 USA

Office: 217.333.1214
Fax: [phone]
[hidden email]
http://core.igb.uiuc.edu

[Peng Xi-2]

 Hi Andreas,
     You may want to read these articles:

R.Wolleschensky1, T. Feurer1, R. Sauerbrey1, U. Simon2 "Characterization and optimization of a laser-scanning microscope in the femtosecond regime", Appl. Phys. B 67, 87–94 (1998)
This paper descirbed how much GDD the microscope system gives.

Jeffrey B. Guild, Chris Xu, and Watt W. Webb, "Measurement of group delay dispersion of high numerical aperture objective lenses using two-photon excited fluorescence",Vol. 36, No. 1 APPLIED OPTICS (1997)

M. Mu¨ ller, J. Squier, R. Wolleschensky, U. Simon, G.J. Brakenhoff, J. Microsc.–Oxford 191 (1998) 141

This two papers measures the GDD of different objectives. The second paper shows how the performance can be improved when GDD is compensated.

P. Xi, Y. Andegeko, L. R. Weisel, V. V. Lozovoy, M. Dantus, "Greater signal, increased depth, and less photobleaching in two-photon microscopy with 10 femtosecond pulses", Optics Communications 281(4), 1841-1849 (2008).
This paper show how the TPM can be improved when both GDD and high-order dispersion is compensated.  :)

    Thank you!

On Sat, Sep 27, 2008 at 1:25 AM, Andreas Bruckbauer <[hidden email]> wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope?

[Peng Xi-2]

Hi Andreas,
     You may want to read these articles:

R.Wolleschensky1, T. Feurer1, R. Sauerbrey1, U. Simon2 "Characterization and optimization of a laser-scanning microscope in the femtosecond regime", Appl. Phys. B 67, 87–94 (1998)
This paper descirbed how much GDD the microscope system gives.

Jeffrey B. Guild, Chris Xu, and Watt W. Webb, "Measurement of group delay dispersion of high numerical aperture objective lenses using two-photon excited fluorescence",Vol. 36, No. 1 APPLIED OPTICS (1997)

M. Mu¨ ller, J. Squier, R. Wolleschensky, U. Simon, G.J. Brakenhoff, J. Microsc.–Oxford 191 (1998) 141

This two papers measures the GDD of different objectives. The second paper shows how the performance can be improved when GDD is compensated.

P. Xi, Y. Andegeko, L. R. Weisel, V. V. Lozovoy, M. Dantus, "Greater signal, increased depth, and less photobleaching in two-photon microscopy with 10 femtosecond pulses", Optics Communications 281(4), 1841-1849 (2008).
This paper show how the TPM can be improved when both GDD and high-order dispersion is compensated.  :)

    Thank you!

Best,
Peng Xi
Head, Laboratory of Biomedical Imaging
Institute for Laser Medicine and Biophotonics
Shanghai Jiao Tong University
800 Dongchuan Rd.
Shanghai 200240, China
Tel: [phone]
Email: [hidden email]
http://biophotonics.sjtu.edu.cn/xipeng/

On Sat, Sep 27, 2008 at 1:25 AM, Andreas Bruckbauer <[hidden email]> wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope?

[Warren Zipfel]

The PDF  I mentioned with some typical MPM dispersion data is on our FTP site at:

ftp://ftp.ccmr.cornell.edu/pub/drbio/Dispersion/

I didn't realize the confocal listserve doesn't allow attachments.

At 04:03 PM 9/26/2008, you wrote:

I do not expect any company can provide these details and its involved work. I know Dr. Warren Zipfel, David Wokosin and others measured these parameters. You can visit the web site given below or talk to Warren
http://www.drbio.cornell.edu/personnel/wrz2.html
Hope this helps
Ammasi
 
 
Ammasi Periasamy, Ph.D.
Director, Keck Center for Cellular Imaging (KCCI)
Professor of Biology and Biomedical Engineering
Biology, Gilmer Hall (064), McCormick Rd
University of Virginia
Charlottesville, VA 22904
Voice: 434-243-7602 (Office); 982-4869 (lab)
Fax:[phone]; Email:[hidden email]
http//:www.kcci.virginia.edu
************************
Workshop on FRET Microscopy, March 3-7, 2009
http://www.kcci.virginia.edu/workshop/workshop2009/index.php
 *************************
 
From: Confocal Microscopy List [[hidden email]] On Behalf Of Mayandi Sivaguru
Sent: Friday, September 26, 2008 3:11 PM
To: [hidden email]
Subject: Re: Pulse broadening in multiphoton micoscopes
 

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use. These measurements are typically done by Application Scientists of the microscope vendors using the lasers either from Spectra or Coherent. Perhaps you can directly contact the head of applications of respective scope manufacturer that whether they have ever measured these peak widths directly on the objectives (air, oil and water immersions) using autocorrelators and so on. For example, you can contact Renee Hessling, Head of Applications, Carl Zeiss, Jena for such data from Zeiss ([hidden email]).
Shiv
 

At 12:25 PM 9/26/2008, you wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope? 

Mayandi Sivaguru, PhD, PhD
Microscopy Facility Manager
8, Institute for Genomic Biology
University of Illinois at Urbana-Champaign
1206 West Gregory Dr.
Urbana, IL 61801 USA

Office: 217.333.1214
Fax: [phone]
[hidden email]
http://core.igb.uiuc.edu

[Craig Brideau]

I'm actually working on a paper regarding this very topic.  I'll be presenting it (if all goes well) at Photonics West this February.  I'll be sure to make sure you folks know about it when it's complete.  The short and sweet answer is that it completely depends on your microscope optics, and the laser companies tend to base their estimates on a 'typical' system.  Understanding of what a typical system is though seems to be a bit spotty, which is why I'm going to try to generate some hard numbers on a variety of lasers and systems.

Craig

On Sat, Sep 27, 2008 at 9:25 AM, Warren Zipfel <[hidden email]> wrote:

The PDF  I mentioned with some typical MPM dispersion data is on our FTP site at:

ftp://ftp.ccmr.cornell.edu/pub/drbio/Dispersion/

I didn't realize the confocal listserve doesn't allow attachments.

At 04:03 PM 9/26/2008, you wrote:

I do not expect any company can provide these details and its involved work. I know Dr. Warren Zipfel, David Wokosin and others measured these parameters. You can visit the web site given below or talk to Warren
http://www.drbio.cornell.edu/personnel/wrz2.html
Hope this helps
Ammasi
 
 
Ammasi Periasamy, Ph.D.
Director, Keck Center for Cellular Imaging (KCCI)
Professor of Biology and Biomedical Engineering
Biology, Gilmer Hall (064), McCormick Rd
University of Virginia
Charlottesville, VA 22904
Voice: 434-243-7602 (Office); 982-4869 (lab)
Fax:[phone]; [hidden email]
http//:www.kcci.virginia.edu
************************
Workshop on FRET Microscopy, March 3-7, 2009
http://www.kcci.virginia.edu/workshop/workshop2009/index.php
 *************************
 
From: Confocal Microscopy List [[hidden email]] On Behalf Of Mayandi Sivaguru
Sent: Friday, September 26, 2008 3:11 PM
To: [hidden email]
Subject: Re: Pulse broadening in multiphoton micoscopes
 

Andreas, I do not think it is the responsibility of the laser manufacturer to provide this data, as this data vary with what kind of optics you use. These measurements are typically done by Application Scientists of the microscope vendors using the lasers either from Spectra or Coherent. Perhaps you can directly contact the head of applications of respective scope manufacturer that whether they have ever measured these peak widths directly on the objectives (air, oil and water immersions) using autocorrelators and so on. For example, you can contact Renee Hessling, Head of Applications, Carl Zeiss, Jena for such data from Zeiss ([hidden email]).
Shiv
 

At 12:25 PM 9/26/2008, you wrote:

Short pulses out of an IR laser broaden considerably when travelling through
dispersive medium, e.g. glass lenses and acoustic optic modulator of a
multi-photon microscope. It is often claimed that shorter pulses broaden
more than longer ones. Does anybody know good literature on this? You can
compensate for this by negative prechirp, would the small difference in
initial pulse width between the Spectra Physics and Coherent lasers have an
effect after prechirp and passing through the microscope? 

Mayandi Sivaguru, PhD, PhD
Microscopy Facility Manager
8, Institute for Genomic Biology
University of Illinois at Urbana-Champaign
1206 West Gregory Dr.
Urbana, IL 61801 USA

Office: 217.333.1214
Fax: [phone]
[hidden email]
http://core.igb.uiuc.edu

[Andreas Bruckbauer]

Thanks a lot for all who replied to my question on and off the list. It
seems that microscope and laser manufacturers now work closely together to
optimize their systems. I came to the conclusion that the remark: "short
pulses will broaden much more"  is not relevant for systems with dispersion
compensation like the current Olympus FV1000 or the MaiTai Deepsee or the
new Coherent vision. These systems have enough compensation to achieve puls
widths out of the objective which are very close to what comes out of the
laser. But the initial difference (140 fs for the Coherent and 100 fs for
the Spectra Physics MaiTai HP) remains. By detuning the dispersion
compensation i can generate longer pulses on the system i am working with
(MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a loss
in fluorescence intensity on a test sample. From this i conclude that the
shorter pulses of the MaiTai can be an advantage.

[Craig Brideau]

Well you can never have pulses shorter than what you start out with.  This means that the 100fs out of the MaiTai will be superior to the Chameleon's 140fs, IF YOU ARE USING DISPERSION CONTROL.  If you are NOT using dispersion control then the Chameleon's 140fs will not broaden as much so you will have better performance.  Bottom line is that pulse width is inversely proportional to dispersion sensitivity.  If you are controlling dispersion with compensation then having short pulses out of the laser is a good thing since you can keep dispersion in check.  Otherwise it will actually perform poorly.  I'm hoping to make this a lot clearer (and backed up with some data) in my paper...

Craig

On Mon, Sep 29, 2008 at 2:16 PM, Andreas Bruckbauer <[hidden email]> wrote:

Thanks a lot for all who replied to my question on and off the list. It
seems that microscope and laser manufacturers now work closely together to
optimize their systems. I came to the conclusion that the remark: "short
pulses will broaden much more"  is not relevant for systems with dispersion
compensation like the current Olympus FV1000 or the MaiTai Deepsee or the
new Coherent vision. These systems have enough compensation to achieve puls
widths out of the objective which are very close to what comes out of the
laser. But the initial difference (140 fs for the Coherent and 100 fs for
the Spectra Physics MaiTai HP) remains. By detuning the dispersion
compensation i can generate longer pulses on the system i am working with
(MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a loss
in fluorescence intensity on a test sample. From this i conclude that the
shorter pulses of the MaiTai can be an advantage.

[Sudipta Maiti]

That's not quite true, the pulses are not necessaily bandwidth limited
as they come out of the box. So after compressing, the 140fs pulse may
become shorter than 100fs. For sure, Chameleon's predecessor (MIRA),
had a chirped output that could be shortened.
Sudipta
On Mon, 29 Sep 2008, Craig
Brideau
wrote:

> Well you can never have pulses shorter than what you start out with.  This
> means that the 100fs out of the MaiTai will be superior to the Chameleon's
> 140fs, IF YOU ARE USING DISPERSION CONTROL.  If you are NOT using dispersion
> control then the Chameleon's 140fs will not broaden as much so you will have
> better performance.  Bottom line is that pulse width is inversely
> proportional to dispersion sensitivity.  If you are controlling dispersion
> with compensation then having short pulses out of the laser is a good thing
> since you can keep dispersion in check.  Otherwise it will actually perform
> poorly.  I'm hoping to make this a lot clearer (and backed up with some
> data) in my paper...
>
> Craig
>
>
> On Mon, Sep 29, 2008 at 2:16 PM, Andreas Bruckbauer <[hidden email]>wrote:
>
>> Thanks a lot for all who replied to my question on and off the list. It
>> seems that microscope and laser manufacturers now work closely together to
>> optimize their systems. I came to the conclusion that the remark: "short
>> pulses will broaden much more"  is not relevant for systems with dispersion
>> compensation like the current Olympus FV1000 or the MaiTai Deepsee or the
>> new Coherent vision. These systems have enough compensation to achieve puls
>> widths out of the objective which are very close to what comes out of the
>> laser. But the initial difference (140 fs for the Coherent and 100 fs for
>> the Spectra Physics MaiTai HP) remains. By detuning the dispersion
>> compensation i can generate longer pulses on the system i am working with
>> (MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a loss
>> in fluorescence intensity on a test sample. From this i conclude that the
>> shorter pulses of the MaiTai can be an advantage.
>>
>

--
Sudipta Maiti
Dept. of Chemical Sciences
Tata Institute of Fundamental Research
Homi Bhabha Road, Colaba, Mumbai 400005, India
91-22-2278-2716
www.tifr.res.in/~biophotonics

[Craig Brideau]

Yes, you always have to base your assumptions on transform limited pulses.  (transform limited = pulse is as short as possible for its bandwidth) Again I hope to get some measurements on all this very soon.  Really, if you assume the availability of a compressor, that means the critical parameter out of an ultrafast laser is its bandwidth rather than its pulsewidth since pulsewidth can be manipulated but its very hard to add more bandwidth.

Thanks for bringing up that point!  It's definitely something I will have to consider.

Craig

On Mon, Sep 29, 2008 at 9:53 PM, Sudipta Maiti <[hidden email]> wrote:

That's not quite true, the pulses are not necessaily bandwidth limited as they come out of the box. So after compressing, the 140fs pulse may become shorter than 100fs. For sure, Chameleon's predecessor (MIRA), had a chirped output that could be shortened.
Sudipta

On Mon, 29 Sep 2008, Craig Brideau wrote:

Well you can never have pulses shorter than what you start out with.  This
means that the 100fs out of the MaiTai will be superior to the Chameleon's
140fs, IF YOU ARE USING DISPERSION CONTROL.  If you are NOT using dispersion
control then the Chameleon's 140fs will not broaden as much so you will have
better performance.  Bottom line is that pulse width is inversely
proportional to dispersion sensitivity.  If you are controlling dispersion
with compensation then having short pulses out of the laser is a good thing
since you can keep dispersion in check.  Otherwise it will actually perform
poorly.  I'm hoping to make this a lot clearer (and backed up with some
data) in my paper...

Craig


On Mon, Sep 29, 2008 at 2:16 PM, Andreas Bruckbauer <[hidden email]>wrote:

Thanks a lot for all who replied to my question on and off the list. It
seems that microscope and laser manufacturers now work closely together to
optimize their systems. I came to the conclusion that the remark: "short
pulses will broaden much more"  is not relevant for systems with dispersion
compensation like the current Olympus FV1000 or the MaiTai Deepsee or the
new Coherent vision. These systems have enough compensation to achieve puls
widths out of the objective which are very close to what comes out of the
laser. But the initial difference (140 fs for the Coherent and 100 fs for
the Spectra Physics MaiTai HP) remains. By detuning the dispersion
compensation i can generate longer pulses on the system i am working with
(MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a loss
in fluorescence intensity on a test sample. From this i conclude that the
shorter pulses of the MaiTai can be an advantage.

--
Sudipta Maiti
Dept. of Chemical Sciences
Tata Institute of Fundamental Research
Homi Bhabha Road, Colaba, Mumbai 400005, India
91-22-2278-2716
www.tifr.res.in/~biophotonics

[A Crane]

There is some information on this from Spectra-Physics at Neuroscience...

Craig Brideau wrote

Yes, you always have to base your assumptions on transform limited pulses.
(transform limited = pulse is as short as possible for its bandwidth) Again
I hope to get some measurements on all this very soon.  Really, if you
assume the availability of a compressor, that means the critical parameter
out of an ultrafast laser is its bandwidth rather than its pulsewidth since
pulsewidth can be manipulated but its very hard to add more bandwidth.

Thanks for bringing up that point!  It's definitely something I will have to
consider.

Craig


On Mon, Sep 29, 2008 at 9:53 PM, Sudipta Maiti
<[e-mail]>wrote:

> That's not quite true, the pulses are not necessaily bandwidth limited as
> they come out of the box. So after compressing, the 140fs pulse may become
> shorter than 100fs. For sure, Chameleon's predecessor (MIRA), had a chirped
> output that could be shortened.
> Sudipta
>
> On Mon, 29 Sep 2008, Craig Brideau wrote:
>
>  Well you can never have pulses shorter than what you start out with.  This
>> means that the 100fs out of the MaiTai will be superior to the Chameleon's
>> 140fs, IF YOU ARE USING DISPERSION CONTROL.  If you are NOT using
>> dispersion
>> control then the Chameleon's 140fs will not broaden as much so you will
>> have
>> better performance.  Bottom line is that pulse width is inversely
>> proportional to dispersion sensitivity.  If you are controlling dispersion
>> with compensation then having short pulses out of the laser is a good
>> thing
>> since you can keep dispersion in check.  Otherwise it will actually
>> perform
>> poorly.  I'm hoping to make this a lot clearer (and backed up with some
>> data) in my paper...
>>
>> Craig
>>
>>
>> On Mon, Sep 29, 2008 at 2:16 PM, Andreas Bruckbauer <[e-mail]
>> >wrote:
>>
>>  Thanks a lot for all who replied to my question on and off the list. It
>>> seems that microscope and laser manufacturers now work closely together
>>> to
>>> optimize their systems. I came to the conclusion that the remark: "short
>>> pulses will broaden much more"  is not relevant for systems with
>>> dispersion
>>> compensation like the current Olympus FV1000 or the MaiTai Deepsee or the
>>> new Coherent vision. These systems have enough compensation to achieve
>>> puls
>>> widths out of the objective which are very close to what comes out of the
>>> laser. But the initial difference (140 fs for the Coherent and 100 fs for
>>> the Spectra Physics MaiTai HP) remains. By detuning the dispersion
>>> compensation i can generate longer pulses on the system i am working with
>>> (MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a
>>> loss
>>> in fluorescence intensity on a test sample. From this i conclude that the
>>> shorter pulses of the MaiTai can be an advantage.
>>>
>>>
>>
> --
> Sudipta Maiti
> Dept. of Chemical Sciences
> Tata Institute of Fundamental Research
> Homi Bhabha Road, Colaba, Mumbai 400005, India
> 91-22-2278-2716
> www.tifr.res.in/~biophotonics <http://www.tifr.res.in/%7Ebiophotonics>
>

[Craig Brideau]

The ultra-broadband lasers just coming out like the one you mention REQUIRE dispersion control.  There is so much spectral content in them that they disperse if you look at them funny. @:-)  On the other hand you can get ~5-10fs pulses with these types of lasers.

Craig

On Tue, Nov 18, 2008 at 3:57 AM, A Crane <[hidden email]> wrote:

Would a system that offered a broader bandwidth be of interest then?

I am not here to advertise but I know that SP have announced a new Mai Tai
at Neuroscience.

Craig Brideau wrote:
>
> Yes, you always have to base your assumptions on transform limited pulses.
> (transform limited = pulse is as short as possible for its bandwidth)
> Again
> I hope to get some measurements on all this very soon.  Really, if you
> assume the availability of a compressor, that means the critical parameter
> out of an ultrafast laser is its bandwidth rather than its pulsewidth
> since
> pulsewidth can be manipulated but its very hard to add more bandwidth.
>
> Thanks for bringing up that point!  It's definitely something I will have
> to
> consider.
>
> Craig
>
>
> On Mon, Sep 29, 2008 at 9:53 PM, Sudipta Maiti
> <[hidden email]>wrote:
>
>> That's not quite true, the pulses are not necessaily bandwidth limited as
>> they come out of the box. So after compressing, the 140fs pulse may
>> become
>> shorter than 100fs. For sure, Chameleon's predecessor (MIRA), had a
>> chirped
>> output that could be shortened.
>> Sudipta
>>
>> On Mon, 29 Sep 2008, Craig Brideau wrote:
>>
>>  Well you can never have pulses shorter than what you start out with.
>> This
>>> means that the 100fs out of the MaiTai will be superior to the
>>> Chameleon's
>>> 140fs, IF YOU ARE USING DISPERSION CONTROL.  If you are NOT using
>>> dispersion
>>> control then the Chameleon's 140fs will not broaden as much so you will
>>> have
>>> better performance.  Bottom line is that pulse width is inversely
>>> proportional to dispersion sensitivity.  If you are controlling
>>> dispersion
>>> with compensation then having short pulses out of the laser is a good
>>> thing
>>> since you can keep dispersion in check.  Otherwise it will actually
>>> perform
>>> poorly.  I'm hoping to make this a lot clearer (and backed up with some
>>> data) in my paper...
>>>
>>> Craig
>>>
>>>
>>> On Mon, Sep 29, 2008 at 2:16 PM, Andreas Bruckbauer <[hidden email]
>>> >wrote:
>>>
>>>  Thanks a lot for all who replied to my question on and off the list. It
>>>> seems that microscope and laser manufacturers now work closely together
>>>> to
>>>> optimize their systems. I came to the conclusion that the remark:
>>>> "short
>>>> pulses will broaden much more"  is not relevant for systems with
>>>> dispersion
>>>> compensation like the current Olympus FV1000 or the MaiTai Deepsee or
>>>> the
>>>> new Coherent vision. These systems have enough compensation to achieve
>>>> puls
>>>> widths out of the objective which are very close to what comes out of
>>>> the
>>>> laser. But the initial difference (140 fs for the Coherent and 100 fs
>>>> for
>>>> the Spectra Physics MaiTai HP) remains. By detuning the dispersion
>>>> compensation i can generate longer pulses on the system i am working
>>>> with
>>>> (MaiTai, Olympus FV1000 with Olympus pre-chirp), this indeed causes a
>>>> loss
>>>> in fluorescence intensity on a test sample. From this i conclude that
>>>> the
>>>> shorter pulses of the MaiTai can be an advantage.
>>>>
>>>>
>>>
>> --
>> Sudipta Maiti
>> Dept. of Chemical Sciences
>> Tata Institute of Fundamental Research
>> Homi Bhabha Road, Colaba, Mumbai 400005, India
>> 91-22-2278-2716

>> www.tifr.res.in/~biophotonics <http://www.tifr.res.in/%7Ebiophotonics>
>>
>
>

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