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
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-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]]
On Behalf Of Patrick Van Oostveldt
Sent: Thursday, 15 October 2009 4:18 AM
To: [log in to unmask]
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 <[log in to unmask]>:
> 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
>> <[log in to unmask]> 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:+47-55 58 67 15
>>>
>
> ----------------------------------------
> Alberto Diaspro
> Head, Nanophysics Unit
> Senior Scientist
> The Italian Institute of Technology -IIT Via Morego, 30
> 16163 - Genova (Italy)
> phone: +39 010 71781503
> mobile: +393666719968
> fax: +39 010 720321
> http://www.iit.it
> [log in to unmask]
>
> Professor of Applied Physics
> Department of Physics
> University of Genova
> Via Dodecaneso, 33
> 16146 Genova - Italy
> tel. +39 010 353 6426
> fax. +39 010 314218
> http://www.lambs.it
> [log in to unmask]
> -------------------------------------------------------
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