Multiphoton - femto vs pico

[Manja Schubert]

Dear Confocal list members,

I have a question to multiphoton technology - femto second IR laser
versus pico second IR laser.
We run in following problem. We have a femto second laser but because of
patent law we can use it only with attenuation filter and a pulse
stretcher meaning in the end we scanning with a pico second IR laser.

Has anyone experienced how that effect the scanning outcome? For
example, the possible deepness of the scan. Any thoughts are highly
appreciated.

Many thanks in advance!

Cheers,
Manja

Dr. Manja Schubert
University of Bergen
Department of Biomedicine
Jonas Lies  vei 91
5009 Bergen
Norway
Tel:[phone]

[Alberto Diaspro]

I would simply remove the crystal, the customer has no patent  
problems...
On Oct 13, 2009, at 9:14 AM, Manja Schubert wrote:

> Dear Confocal list members,
>
> I have a question to multiphoton technology - femto second IR laser  
> versus pico second IR laser.
> We run in following problem. We have a femto second laser but  
> because of patent law we can use it only with attenuation filter and  
> a pulse stretcher meaning in the end we scanning with a pico second  
> IR laser.
>
> Has anyone experienced how that effect the scanning outcome? For  
> example, the possible deepness of the scan. Any thoughts are highly  
> appreciated.
>
> Many thanks in advance!
>
> Cheers,
> Manja
>
> Dr. Manja Schubert
> University of Bergen
> Department of Biomedicine
> Jonas Lies  vei 91
> 5009 Bergen
> Norway
> Tel:[phone]

----------------------------------------
Alberto Diaspro
Head, Nanophysics Unit
Senior Scientist
The Italian Institute of Technology -IIT
Via Morego, 30
16163 - Genova (Italy)
phone: [phone]
mobile: [phone]
fax:   [phone]
http://www.iit.it
[hidden email]

Professor of Applied Physics
Department of Physics
University of Genova
Via Dodecaneso, 33
16146 Genova - Italy
tel.  [phone]
fax. [phone]
http://www.lambs.it
[hidden email]
-------------------------------------------------------

[Christian Liebig]

But that would also involve realignment of the laser, doesn't it?

Kind regards,

Christian



Alberto Diaspro wrote:

> I would simply remove the crystal, the customer has no patent  
> problems...
> On Oct 13, 2009, at 9:14 AM, Manja Schubert wrote:
>
>  
>> Dear Confocal list members,
>>
>> I have a question to multiphoton technology - femto second IR laser  
>> versus pico second IR laser.
>> We run in following problem. We have a femto second laser but  
>> because of patent law we can use it only with attenuation filter and  
>> a pulse stretcher meaning in the end we scanning with a pico second  
>> IR laser.
>>
>> Has anyone experienced how that effect the scanning outcome? For  
>> example, the possible deepness of the scan. Any thoughts are highly  
>> appreciated.
>>
>> Many thanks in advance!
>>
>> Cheers,
>> Manja
>>
>> Dr. Manja Schubert
>> University of Bergen
>> Department of Biomedicine
>> Jonas Lies  vei 91
>> 5009 Bergen
>> Norway
>> Tel:[phone]
>>    
>
> ----------------------------------------
> Alberto Diaspro
> Head, Nanophysics Unit
> Senior Scientist
> The Italian Institute of Technology -IIT
> Via Morego, 30
> 16163 - Genova (Italy)
> phone: [phone]
> mobile: [phone]
> fax:   [phone]
> http://www.iit.it
> [hidden email]
>
> Professor of Applied Physics
> Department of Physics
> University of Genova
> Via Dodecaneso, 33
> 16146 Genova - Italy
> tel.  [phone]
> fax. [phone]
> http://www.lambs.it
> [hidden email]
> -------------------------------------------------------
>  

--



Christian Liebig, PhD

FILM - Facility for Imaging by Light Microscopy
- Facility Assistant -
Sir Alexander Fleming Building, desk 403
Imperial College London / South Kensington
Exhibition Road
London SW7 2AZ
UK

Tel. [phone]
Fax [phone]
E-mail [hidden email]
Website: http://imperial.ac.uk/imagingfacility

[Alberto Diaspro]

yes but it is simpler than when you have the crystal
On Oct 13, 2009, at 10:44 AM, Christian Liebig wrote:

> But that would also involve realignment of the laser, doesn't it?
>
> Kind regards,
>
> Christian
>
>
>
> Alberto Diaspro wrote:
>> I would simply remove the crystal, the customer has no patent  
>> problems...
>> On Oct 13, 2009, at 9:14 AM, Manja Schubert wrote:
>>
>>
>>> Dear Confocal list members,
>>>
>>> I have a question to multiphoton technology - femto second IR  
>>> laser  versus pico second IR laser.
>>> We run in following problem. We have a femto second laser but  
>>> because of patent law we can use it only with attenuation filter  
>>> and  a pulse stretcher meaning in the end we scanning with a pico  
>>> second  IR laser.
>>>
>>> Has anyone experienced how that effect the scanning outcome? For  
>>> example, the possible deepness of the scan. Any thoughts are  
>>> highly  appreciated.
>>>
>>> Many thanks in advance!
>>>
>>> Cheers,
>>> Manja
>>>
>>> Dr. Manja Schubert
>>> University of Bergen
>>> Department of Biomedicine
>>> Jonas Lies  vei 91
>>> 5009 Bergen
>>> Norway
>>> Tel:[phone]
>>>
>>
>> ----------------------------------------
>> Alberto Diaspro
>> Head, Nanophysics Unit
>> Senior Scientist
>> The Italian Institute of Technology -IIT
>> Via Morego, 30
>> 16163 - Genova (Italy)
>> phone: [phone]
>> mobile: [phone]
>> fax:   [phone]
>> http://www.iit.it
>> [hidden email]
>>
>> Professor of Applied Physics
>> Department of Physics
>> University of Genova
>> Via Dodecaneso, 33
>> 16146 Genova - Italy
>> tel.  [phone]
>> fax. [phone]
>> http://www.lambs.it
>> [hidden email]
>> -------------------------------------------------------
>>
>
>
> --
>
>
>
> Christian Liebig, PhD
>
> FILM - Facility for Imaging by Light Microscopy
> - Facility Assistant -
> Sir Alexander Fleming Building, desk 403
> Imperial College London / South Kensington
> Exhibition Road
> London SW7 2AZ
> UK
>
> Tel. [phone]
> Fax [phone]
> E-mail [hidden email]
> Website: http://imperial.ac.uk/imagingfacility

----------------------------------------
Alberto Diaspro
Head, Nanophysics Unit
Senior Scientist
The Italian Institute of Technology -IIT
Via Morego, 30
16163 - Genova (Italy)
phone: [phone]
mobile: [phone]
fax:   [phone]
http://www.iit.it
[hidden email]

Professor of Applied Physics
Department of Physics
University of Genova
Via Dodecaneso, 33
16146 Genova - Italy
tel.  [phone]
fax. [phone]
http://www.lambs.it
[hidden email]
-------------------------------------------------------

[Sudipta Maiti]

Of course, Alby has a simple solution. Otherwise:

Your two photon excitation probability is inversely proportional to the
pulsewidth, so by going to 1 ps from 100 fs you would lose a factor of 10.
Can make it up by factor of 3.1 (sq. rt. 10) higher power, but the sample
may burn.
Two points:
1) if you can re-jig the stretcher to give you negatively chirped ps pulses,
you may effectively be doing fs excitation at the sample - do check if the
laws allow it.
2) The two photon patent must be coming to an end about now - check with
your supplier!

Sudipta

and On Tue, 13 Oct 2009 10:48:16 +0200, Alberto Diaspro wrote

> yes but it is simpler than when you have the crystal
> On Oct 13, 2009, at 10:44 AM, Christian Liebig wrote:
>
> > But that would also involve realignment of the laser, doesn't it?
> >
> > Kind regards,
> >
> > Christian
> >
> >
> >
> > Alberto Diaspro wrote:
> >> I would simply remove the crystal, the customer has no patent  
> >> problems...
> >> On Oct 13, 2009, at 9:14 AM, Manja Schubert wrote:
> >>
> >>
> >>> Dear Confocal list members,
> >>>
> >>> I have a question to multiphoton technology - femto second IR  
> >>> laser  versus pico second IR laser.
> >>> We run in following problem. We have a femto second laser but  
> >>> because of patent law we can use it only with attenuation filter  
> >>> and  a pulse stretcher meaning in the end we scanning with a pico  
> >>> second  IR laser.
> >>>
> >>> Has anyone experienced how that effect the scanning outcome? For  
> >>> example, the possible deepness of the scan. Any thoughts are  
> >>> highly  appreciated.
> >>>
> >>> Many thanks in advance!
> >>>
> >>> Cheers,
> >>> Manja
> >>>
> >>> Dr. Manja Schubert
> >>> University of Bergen
> >>> Department of Biomedicine
> >>> Jonas Lies  vei 91
> >>> 5009 Bergen
> >>> Norway
> >>> Tel:[phone]
> >>>
> >>
> >> ----------------------------------------
> >> Alberto Diaspro
> >> Head, Nanophysics Unit
> >> Senior Scientist
> >> The Italian Institute of Technology -IIT
> >> Via Morego, 30
> >> 16163 - Genova (Italy)
> >> phone: [phone]
> >> mobile: [phone]
> >> fax:   [phone]
> >> http://www.iit.it
> >> [hidden email]
> >>
> >> Professor of Applied Physics
> >> Department of Physics
> >> University of Genova
> >> Via Dodecaneso, 33
> >> 16146 Genova - Italy
> >> tel.  [phone]
> >> fax. [phone]
> >> http://www.lambs.it
> >> [hidden email]
> >> -------------------------------------------------------
> >>
> >
> >
> > --
> >
> >
> >
> > Christian Liebig, PhD
> >
> > FILM - Facility for Imaging by Light Microscopy
> > - Facility Assistant -
> > Sir Alexander Fleming Building, desk 403
> > Imperial College London / South Kensington
> > Exhibition Road
> > London SW7 2AZ
> > UK
> >
> > Tel. [phone]
> > Fax [phone]
> > E-mail [hidden email]
> > Website: http://imperial.ac.uk/imagingfacility
>
> ----------------------------------------
> Alberto Diaspro
> Head, Nanophysics Unit
> Senior Scientist
> The Italian Institute of Technology -IIT
> Via Morego, 30
> 16163 - Genova (Italy)
> phone: [phone]
> mobile: [phone]
> fax:   [phone]
> http://www.iit.it
> [hidden email]
>
> Professor of Applied Physics
> Department of Physics
> University of Genova
> Via Dodecaneso, 33
> 16146 Genova - Italy
> tel.  [phone]
> fax. [phone]
> http://www.lambs.it
> [hidden email]
> -------------------------------------------------------

Dr. Sudipta Maiti
Associate Professor
Dept. of Chemical Sciences
Tata Institute of Fundamental Research
Homi Bhabha Raod, Colaba, Mumbai 400005
Ph. 91-22-2278-2716 / 2539
Fax: [phone]
alternate e-mail: [hidden email]
url: biophotonics.wetpaint.com

[Evangelos Gatzogiannis]

      Femto is not always necessarily better.   You can safely use more
average power with picosecond compared to femtosecond to go deep into
brain or muscle tissue.  I have found that picosecond is /sometimes/
better than femtosecond, even for SHG.  Femtosecond will give more
initial signal but picosecond signal will stay constant, longer, at the
same power, in tissue.  Also, for our confocal core's speciality: CARS
microscopy, picosecond is far superior in that it matches the
vibrational linewidths and doesn't dump a lot of energy in a broad
spectral region like femtosecond pulses.  Dispersion is far less of a
problem with pico and not as much need to pre-comp, but I do believe for
THG, and if you have very weak 2-photon signal you would have to used
pre-chirped compressed femtosecond pulses, with SHG on collagen,
2-photon with more average power, and CARS you're ok with pico,
otherwise you need femto.

Best,
Evangelos

Advanced Biological Imaging Scientist
Harvard Center for Nanoscale Systems
11 Oxford Street
Cambridge, MA 02138

Manja Schubert wrote:

> Dear Confocal list members,
>
> I have a question to multiphoton technology - femto second IR laser
> versus pico second IR laser.
> We run in following problem. We have a femto second laser but because
> of patent law we can use it only with attenuation filter and a pulse
> stretcher meaning in the end we scanning with a pico second IR laser.
>
> Has anyone experienced how that effect the scanning outcome? For
> example, the possible deepness of the scan. Any thoughts are highly
> appreciated.
>
> Many thanks in advance!
>
> Cheers,
> Manja
>
> Dr. Manja Schubert
> University of Bergen
> Department of Biomedicine
> Jonas Lies  vei 91
> 5009 Bergen
> Norway
> Tel:[phone]

[Craig Brideau]

You must have some strange patent issues.  I am not a lawyer, so take
what I say with a grain of salt, however it seems that as long as it
is for use in your own lab and you are not selling a product involving
fs lasers or otherwise profiting then you should be within your rights
to simply remove the stretcher block from your system.

Craig


On Tue, Oct 13, 2009 at 7:26 AM, Evangelos <[hidden email]> wrote:

>     Femto is not always necessarily better.   You can safely use more
> average power with picosecond compared to femtosecond to go deep into brain
> or muscle tissue.  I have found that picosecond is /sometimes/ better than
> femtosecond, even for SHG.  Femtosecond will give more initial signal but
> picosecond signal will stay constant, longer, at the same power, in tissue.
>  Also, for our confocal core's speciality: CARS microscopy, picosecond is
> far superior in that it matches the vibrational linewidths and doesn't dump
> a lot of energy in a broad spectral region like femtosecond pulses.
>  Dispersion is far less of a problem with pico and not as much need to
> pre-comp, but I do believe for THG, and if you have very weak 2-photon
> signal you would have to used pre-chirped compressed femtosecond pulses,
> with SHG on collagen, 2-photon with more average power, and CARS you're ok
> with pico, otherwise you need femto.
>
> Best,
> Evangelos
>
> Advanced Biological Imaging Scientist
> Harvard Center for Nanoscale Systems
> 11 Oxford Street
> Cambridge, MA 02138
>
> Manja Schubert wrote:
>>
>> Dear Confocal list members,
>>
>> I have a question to multiphoton technology - femto second IR laser versus
>> pico second IR laser.
>> We run in following problem. We have a femto second laser but because of
>> patent law we can use it only with attenuation filter and a pulse stretcher
>> meaning in the end we scanning with a pico second IR laser.
>>
>> Has anyone experienced how that effect the scanning outcome? For example,
>> the possible deepness of the scan. Any thoughts are highly appreciated.
>>
>> Many thanks in advance!
>>
>> Cheers,
>> Manja
>>
>> Dr. Manja Schubert
>> University of Bergen
>> Department of Biomedicine
>> Jonas Lies  vei 91
>> 5009 Bergen
>> Norway
>> Tel:[phone]
>

[Alberto Diaspro]

Friends
I think that everything is really simpler. Removing the crystal is a  
simple operation and re-alignement as well.
I agree that fs is not always better than ps, this can depend on your  
own need.

We performed imaging both using ps and fs. I do not have any strange  
patent issue, I simply try to make research. I fully understand all  
the patent issues and I do respect them, even if I continue thinking  
that the TPE patent blocked research in the field for some years with  
exceptions. It is well now that ALL microscopy companies can provide  
systems that can be adapted for multiphoton imaging including SHG  
etc... It is also very well known that in some cases there is the need  
for special techniques but people managing the microscopy lab do not  
have resources or time that can be devoted to users, bright users,  
that do not want to be active part of the image formation process  
having their own research plan. I think that any attempt of perfoming  
microscopy imaging has to be helped and favoured, when possible.

This list is a great source of help, so please, make your experimental  
designs without thinking about patents, ask your questions...get the  
answers...not always you can get the right one but everything can help  
growth ...
All the best
Alby


On Oct 13, 2009, at 5:26 PM, Craig Brideau wrote:

> You must have some strange patent issues.  I am not a lawyer, so take
> what I say with a grain of salt, however it seems that as long as it
> is for use in your own lab and you are not selling a product involving
> fs lasers or otherwise profiting then you should be within your rights
> to simply remove the stretcher block from your system.
>
> Craig
>
>
> On Tue, Oct 13, 2009 at 7:26 AM, Evangelos <[hidden email]
> > wrote:
>>     Femto is not always necessarily better.   You can safely use more
>> average power with picosecond compared to femtosecond to go deep  
>> into brain
>> or muscle tissue.  I have found that picosecond is /sometimes/  
>> better than
>> femtosecond, even for SHG.  Femtosecond will give more initial  
>> signal but
>> picosecond signal will stay constant, longer, at the same power, in  
>> tissue.
>>  Also, for our confocal core's speciality: CARS microscopy,  
>> picosecond is
>> far superior in that it matches the vibrational linewidths and  
>> doesn't dump
>> a lot of energy in a broad spectral region like femtosecond pulses.
>>  Dispersion is far less of a problem with pico and not as much need  
>> to
>> pre-comp, but I do believe for THG, and if you have very weak 2-
>> photon
>> signal you would have to used pre-chirped compressed femtosecond  
>> pulses,
>> with SHG on collagen, 2-photon with more average power, and CARS  
>> you're ok
>> with pico, otherwise you need femto.
>>
>> Best,
>> Evangelos
>>
>> Advanced Biological Imaging Scientist
>> Harvard Center for Nanoscale Systems
>> 11 Oxford Street
>> Cambridge, MA 02138
>>
>> Manja Schubert wrote:
>>>
>>> Dear Confocal list members,
>>>
>>> I have a question to multiphoton technology - femto second IR  
>>> laser versus
>>> pico second IR laser.
>>> We run in following problem. We have a femto second laser but  
>>> because of
>>> patent law we can use it only with attenuation filter and a pulse  
>>> stretcher
>>> meaning in the end we scanning with a pico second IR laser.
>>>
>>> Has anyone experienced how that effect the scanning outcome? For  
>>> example,
>>> the possible deepness of the scan. Any thoughts are highly  
>>> appreciated.
>>>
>>> Many thanks in advance!
>>>
>>> Cheers,
>>> Manja
>>>
>>> Dr. Manja Schubert
>>> University of Bergen
>>> Department of Biomedicine
>>> Jonas Lies  vei 91
>>> 5009 Bergen
>>> Norway
>>> Tel:[phone]
>>

----------------------------------------
Alberto Diaspro
Head, Nanophysics Unit
Senior Scientist
The Italian Institute of Technology -IIT
Via Morego, 30
16163 - Genova (Italy)
phone: [phone]
mobile: [phone]
fax:   [phone]
http://www.iit.it
[hidden email]

Professor of Applied Physics
Department of Physics
University of Genova
Via Dodecaneso, 33
16146 Genova - Italy
tel.  [phone]
fax. [phone]
http://www.lambs.it
[hidden email]
-------------------------------------------------------

[Patrick Van Oostveldt]

Dear Friends,

I like to express my sympathy witk Alberto.
Indeed as he stated a lot of patenting has retarded TPE. The pitty  
thing is that our universities purge us to do research and validate  
our research with patents, and the results is that to continu research  
we need spend money to pay the royalties of our collegas at the  
university.

In this way, the snake is byting its tail.

Greetings hut not seeing a reasonable solution

Patrick

Quoting Alberto Diaspro <[hidden email]>:

> Friends
> I think that everything is really simpler. Removing the crystal is a
> simple operation and re-alignement as well.
> I agree that fs is not always better than ps, this can depend on your
> own need.
>
> We performed imaging both using ps and fs. I do not have any strange
> patent issue, I simply try to make research. I fully understand all the
> patent issues and I do respect them, even if I continue thinking that
> the TPE patent blocked research in the field for some years with
> exceptions. It is well now that ALL microscopy companies can provide
> systems that can be adapted for multiphoton imaging including SHG
> etc... It is also very well known that in some cases there is the need
> for special techniques but people managing the microscopy lab do not
> have resources or time that can be devoted to users, bright users, that
> do not want to be active part of the image formation process having
> their own research plan. I think that any attempt of perfoming
> microscopy imaging has to be helped and favoured, when possible.
>
> This list is a great source of help, so please, make your experimental
> designs without thinking about patents, ask your questions...get the
> answers...not always you can get the right one but everything can help
> growth ...
> All the best
> Alby
>
>
> On Oct 13, 2009, at 5:26 PM, Craig Brideau wrote:
>
>> You must have some strange patent issues.  I am not a lawyer, so take
>> what I say with a grain of salt, however it seems that as long as it
>> is for use in your own lab and you are not selling a product involving
>> fs lasers or otherwise profiting then you should be within your rights
>> to simply remove the stretcher block from your system.
>>
>> Craig
>>
>>
>> On Tue, Oct 13, 2009 at 7:26 AM, Evangelos  
>> <[hidden email]> wrote:
>>>    Femto is not always necessarily better.   You can safely use more
>>> average power with picosecond compared to femtosecond to go deep into brain
>>> or muscle tissue.  I have found that picosecond is /sometimes/ better than
>>> femtosecond, even for SHG.  Femtosecond will give more initial signal but
>>> picosecond signal will stay constant, longer, at the same power, in tissue.
>>> Also, for our confocal core's speciality: CARS microscopy, picosecond is
>>> far superior in that it matches the vibrational linewidths and doesn't dump
>>> a lot of energy in a broad spectral region like femtosecond pulses.
>>> Dispersion is far less of a problem with pico and not as much need to
>>> pre-comp, but I do believe for THG, and if you have very weak 2-photon
>>> signal you would have to used pre-chirped compressed femtosecond pulses,
>>> with SHG on collagen, 2-photon with more average power, and CARS you're ok
>>> with pico, otherwise you need femto.
>>>
>>> Best,
>>> Evangelos
>>>
>>> Advanced Biological Imaging Scientist
>>> Harvard Center for Nanoscale Systems
>>> 11 Oxford Street
>>> Cambridge, MA 02138
>>>
>>> Manja Schubert wrote:
>>>>
>>>> Dear Confocal list members,
>>>>
>>>> I have a question to multiphoton technology - femto second IR laser versus
>>>> pico second IR laser.
>>>> We run in following problem. We have a femto second laser but because of
>>>> patent law we can use it only with attenuation filter and a pulse  
>>>>  stretcher
>>>> meaning in the end we scanning with a pico second IR laser.
>>>>
>>>> Has anyone experienced how that effect the scanning outcome? For example,
>>>> the possible deepness of the scan. Any thoughts are highly appreciated.
>>>>
>>>> Many thanks in advance!
>>>>
>>>> Cheers,
>>>> Manja
>>>>
>>>> Dr. Manja Schubert
>>>> University of Bergen
>>>> Department of Biomedicine
>>>> Jonas Lies  vei 91
>>>> 5009 Bergen
>>>> Norway
>>>> Tel:[phone]
>>>
>
> ----------------------------------------
> Alberto Diaspro
> Head, Nanophysics Unit
> Senior Scientist
> The Italian Institute of Technology -IIT
> Via Morego, 30
> 16163 - Genova (Italy)
> phone: [phone]
> mobile: [phone]
> fax:   [phone]
> http://www.iit.it
> [hidden email]
>
> Professor of Applied Physics
> Department of Physics
> University of Genova
> Via Dodecaneso, 33
> 16146 Genova - Italy
> tel.  [phone]
> fax. [phone]
> http://www.lambs.it
> [hidden email]
> -------------------------------------------------------

--
Dep. Moleculaire Biotechnologie
Coupure links 653
B 9000 GENT

tel [phone]
fax [phone]

[Guy Cox]

As I understand it, it was stated from the start that the Cornell patent
on two-photon imaging was never going to be used to prosecute labs
making their own systems.  So there is no problem with a 'do it
yourself' removal of the pulse stretcher.  What is also relevant is that
Leica has now licensed to use femtosecond, so they could presumably
convert your system (but I suppose they'd have to charge you the license
fee).  

                                  Guy



Optical Imaging Techniques in Cell Biology
by Guy Cox    CRC Press / Taylor & Francis
    http://www.guycox.com/optical.htm
______________________________________________
Associate Professor Guy Cox, MA, DPhil(Oxon)
Electron Microscope Unit, Madsen Building F09,
University of Sydney, NSW 2006
______________________________________________
Phone [phone]     Fax [phone]
Mobile [phone]
______________________________________________
     http://www.guycox.net
-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]]
On Behalf Of Patrick Van Oostveldt
Sent: Thursday, 15 October 2009 4:18 AM
To: [hidden email]
Subject: Re: Multiphoton - femto vs pico

Dear Friends,

I like to express my sympathy witk Alberto.
Indeed as he stated a lot of patenting has retarded TPE. The pitty thing
is that our universities purge us to do research and validate our
research with patents, and the results is that to continu research we
need spend money to pay the royalties of our collegas at the university.

In this way, the snake is byting its tail.

Greetings hut not seeing a reasonable solution

Patrick

Quoting Alberto Diaspro <[hidden email]>:

> Friends
> I think that everything is really simpler. Removing the crystal is a
> simple operation and re-alignement as well.
> I agree that fs is not always better than ps, this can depend on your
> own need.
>
> We performed imaging both using ps and fs. I do not have any strange
> patent issue, I simply try to make research. I fully understand all
> the patent issues and I do respect them, even if I continue thinking
> that the TPE patent blocked research in the field for some years with
> exceptions. It is well now that ALL microscopy companies can provide
> systems that can be adapted for multiphoton imaging including SHG
> etc... It is also very well known that in some cases there is the need

> for special techniques but people managing the microscopy lab do not
> have resources or time that can be devoted to users, bright users,
> that do not want to be active part of the image formation process
> having their own research plan. I think that any attempt of perfoming
> microscopy imaging has to be helped and favoured, when possible.
>
> This list is a great source of help, so please, make your experimental

> designs without thinking about patents, ask your questions...get the
> answers...not always you can get the right one but everything can help

> growth ...
> All the best
> Alby
>
>
> On Oct 13, 2009, at 5:26 PM, Craig Brideau wrote:
>
>> You must have some strange patent issues.  I am not a lawyer, so take

>> what I say with a grain of salt, however it seems that as long as it
>> is for use in your own lab and you are not selling a product
>> involving fs lasers or otherwise profiting then you should be within
>> your rights to simply remove the stretcher block from your system.
>>
>> Craig
>>
>>
>> On Tue, Oct 13, 2009 at 7:26 AM, Evangelos  
>> <[hidden email]> wrote:
>>>    Femto is not always necessarily better.   You can safely use more
>>> average power with picosecond compared to femtosecond to go deep
>>> into brain or muscle tissue.  I have found that picosecond is
>>> /sometimes/ better than femtosecond, even for SHG.  Femtosecond will

>>> give more initial signal but picosecond signal will stay constant,
longer, at the same power, in tissue.
>>> Also, for our confocal core's speciality: CARS microscopy,
>>> picosecond is far superior in that it matches the vibrational
>>> linewidths and doesn't dump a lot of energy in a broad spectral
region like femtosecond pulses.
>>> Dispersion is far less of a problem with pico and not as much need
>>> to pre-comp, but I do believe for THG, and if you have very weak
>>> 2-photon signal you would have to used pre-chirped compressed
>>> femtosecond pulses, with SHG on collagen, 2-photon with more average

>>> power, and CARS you're ok with pico, otherwise you need femto.
>>>
>>> Best,
>>> Evangelos
>>>
>>> Advanced Biological Imaging Scientist Harvard Center for Nanoscale
>>> Systems
>>> 11 Oxford Street
>>> Cambridge, MA 02138
>>>
>>> Manja Schubert wrote:
>>>>
>>>> Dear Confocal list members,
>>>>
>>>> I have a question to multiphoton technology - femto second IR laser

>>>> versus pico second IR laser.
>>>> We run in following problem. We have a femto second laser but
>>>> because of patent law we can use it only with attenuation filter
>>>> and a pulse  stretcher meaning in the end we scanning with a pico
>>>> second IR laser.
>>>>
>>>> Has anyone experienced how that effect the scanning outcome? For
>>>> example, the possible deepness of the scan. Any thoughts are highly
appreciated.

>>>>
>>>> Many thanks in advance!
>>>>
>>>> Cheers,
>>>> Manja
>>>>
>>>> Dr. Manja Schubert
>>>> University of Bergen
>>>> Department of Biomedicine
>>>> Jonas Lies  vei 91
>>>> 5009 Bergen
>>>> Norway
>>>> Tel:[phone]
>>>
>
> ----------------------------------------
> Alberto Diaspro
> Head, Nanophysics Unit
> Senior Scientist
> The Italian Institute of Technology -IIT Via Morego, 30
> 16163 - Genova (Italy)
> phone: [phone]
> mobile: [phone]
> fax:   [phone]
> http://www.iit.it
> [hidden email]
>
> Professor of Applied Physics
> Department of Physics
> University of Genova
> Via Dodecaneso, 33
> 16146 Genova - Italy
> tel.  [phone]
> fax. [phone]
> http://www.lambs.it
> [hidden email]
> -------------------------------------------------------

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[Evangelos Gatzogiannis]

  From what I thought with Leica and the patent that is now up, you are free
to do what you want with your laser - but the Leica support is gone and the
Leica reps won't be in the room and won't help you if you do.  But that is
chaning, Zeiss of course sub-licensed two photon for the Olympus FV1000 and
should be doing so with Leica now.  The ridiculous thing in my view, for
people like me who build oscillators/opos and go back and forth from
femtosecond to picosecond all the time in my lab depending on what is best
for the student, is the idea that some day there may be a patent, "imaging
with sub 100fs" or "imaging with 2+ps" putting us all in a tight box, but I
have hope - when your lab gets to be like mine, all wires, all
home-modified, older equipment, jerry-rigged there are neither
service/support or patent issues to worry about.  If you're willing to be on
your own without help you can do what you wish, but I'm not a lawyer.

-Evangelos