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It could be but I don't know, what does the manufacturer say?
Mark
On 29/04/2011, at 8:08 AM, Craig Brideau wrote:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
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>
> Is that the stuff they use on certain IR detector cards? I have a
> type that
> absorbs NIR and emits in the green. It doesn't require charging
> like the
> other types (luminescent) so I always assumed it was some sort of
> anti-stokes material.
>
> Craig
>
>
> On Thu, Apr 28, 2011 at 9:54 AM, Mark Cannell <[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
>> *****
>>
>> Yes:
>> "When a system (be it a molecule or atom) absorbs a photon, it
>> gains energy
>> and enters an excited state. One way for the system to relax is to
>> emit a
>> photon, thus losing its energy (another method would be the loss of
>> heat
>> energy). When the emitted photon has less energy than the absorbed
>> photon,
>> this energy difference is the Stokes shift. If the emitted photon
>> has more
>> energy, the energy difference is called an anti-Stokes shift;[3]
>> this extra
>> energy comes from dissipation of thermal phonons in a crystal
>> lattice,
>> cooling the crystal in the process. Yttrium oxysulfidedoped with
>> gadolinium
>> oxysulfide is a common industrial anti-Stokes pigment, absorbing in
>> the
>> near-infrared and emitting in the visible portion of the spectrum."
>> http://en.wikipedia.org/wiki/Stokes_shift
>>
>> Hope this helps, Mark
>>
>>
>>
>> On 29/04/2011, at 2:10 AM, Coutu, Cathy wrote:
>>
>> *****
>>> To join, leave or search the confocal microscopy listserv, go to:
>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>> *****
>>>
>>> Sorry, but I'm not familiar with an "antistokes shift". Would
>>> that be an
>>> emission with a shorter wavelength than the excitation???
>>>
>>> Cathy
>>>
>>> Cathy Coutu, M. Sc.
>>> Technician / Technicienne
>>> Genomics, Bioinformatics, and other Bioinformation / Génomique,
>>> Bioinformatique et Bioinformation
>>> Agriculture and Agri-Food Canada/Agriculture et Agroalimentaire
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>>>
>>> -----Original Message-----
>>> From: Confocal Microscopy List [mailto:[log in to unmask]
>>> ]
>>> On Behalf Of Mark Cannell
>>> Sent: April-28-11 4:43 AM
>>> To: [log in to unmask]
>>> Subject: Re: same excitation and emission peaks
>>>
>>> *****
>>> To join, leave or search the confocal microscopy listserv, go to:
>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>> *****
>>>
>>> Quite so. But in this case he's not looking for an antistokes shift
>>> just re-emission of the same apparent energy. It's the lower
>>> probability of re-emission at this wavelength that prevents
>>> violation
>>> of the second law.
>>>
>>> Cheers
>>>
>>> On 28/04/2011, at 10:30 PM, Andreas Bruckbauer wrote:
>>>
>>> *****
>>>> To join, leave or search the confocal microscopy listserv, go to:
>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>> *****
>>>>
>>>>
>>>>
>>>> To distinguish between Rayleigh or Mie scattering ('reflection')
>>>> and
>>>> photoluminescence you would need to measure time resolved, see e.g.
>>>> G. Plesson et al. PHYSICAL REVIEW B 70, 205424 (2004). What you
>>>> measure is most likely the excitation light, but you could try to
>>>> vary the with of the excitation line if this is possible in your
>>>> instrument and see if the peak varies accordingly.
>>>>
>>>> I think what Mark meant was the interaction of the excited electron
>>>> with phonons, usually the energy is dissipated as phonons but you
>>>> could also have phonons transferring energy to the electron in
>>>> which
>>>> case it would gain energy from the phonon. If it does not relax
>>>> further and goes back into the ground state by emitting a photon,
>>>> you will get anti stokes fluorescence. At room temperature the
>>>> energy of a single phonon would be around kT (25 meV compared to 3
>>>> eV for a blue photon), so you need a lot of electron-phonon
>>>> interaction to make a noticable shift.
>>>>
>>>> In case of the metal particle you will also have plasmon
>>>> excitation.
>>>>
>>>> best wishes
>>>>
>>>> Andreas
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Johannes-P. Koch <[log in to unmask]>
>>>> To: [log in to unmask]
>>>> Sent: Thu, 28 Apr 2011 8:27
>>>> Subject: Re: same excitation and emission peaks
>>>>
>>>>
>>>> *****
>>>> To join, leave or search the confocal microscopy listserv, go to:
>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>> *****
>>>>
>>>> Think so too; if you measure something in a fluorimeter, you always
>>>> get a scattering "line" or peak (if looking at your spectra in 2D)!
>>>>
>>>>
>>>> Mark, could you comment on your phonon stuff?
>>>>
>>>> To my knowledge, phonons as such do not fluoresce; they do interact
>>>> with photons, i.e. you can generate a fluorescing photon by
>>>> annihilating a phonon or vice versa; still wherever you go, their
>>>> is
>>>> some loss of energy, meaning that you cannot have exactly the same
>>>> peaks. - probabilistic or not!
>>>>
>>>> Johannes
>>>>
>>>> Am 28.04.2011 08:57, schrieb Sudipta Maiti:
>>>>
>>>>> *****
>>>>> To join, leave or search the confocal microscopy listserv, go to:
>>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>>> *****
>>>>>
>>>>> are you not just looking at Rayleigh scattering?
>>>>> Sudipta
>>>>> On Thu, 28 Apr 2011 12:24:29 +0530, charu tanwar wrote
>>>>>
>>>>>> *****
>>>>>> To join, leave or search the confocal microscopy listserv, go to:
>>>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>>>> *****
>>>>>>
>>>>>> yes...that is what i also thought of. But this is the data we are
>>>>>> getting after repeatedly doing the experiment. Thanks
>>>>>>
>>>>>> CHARU TANWAR
>>>>>> Imaging Specialist
>>>>>> Advanced Instrumentation Research Facility
>>>>>> Jawaharlal Nehru University
>>>>>> New Delhi 110067
>>>>>> India.
>>>>>>
>>>>>> --- On Wed, 27/4/11, Jeffrey L. Travis<[log in to unmask]> wrote:
>>>>>>
>>>>>> From: Jeffrey L. Travis<[log in to unmask]>
>>>>>> Subject: Re: same excitation and emission peaks
>>>>>> To: [log in to unmask]
>>>>>> Date: Wednesday, 27 April, 2011, 7:33 PM
>>>>>>
>>>>>> *****
>>>>>> To join, leave or search the confocal microscopy listserv, go to:
>>>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>>>> *****
>>>>>>
>>>>>> Wouldn't that violate the Second Law?
>>>>>>
>>>>>> On 4/27/2011 9:59 AM, Charu Tanwar wrote:
>>>>>>
>>>>>>> *****
>>>>>>> To join, leave or search the confocal microscopy listserv, go
>>>>>>> to:
>>>>>>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>>>>>>> *****
>>>>>>>
>>>>>>> Dear List
>>>>>>>
>>>>>>> Not a direct confocal related query.
>>>>>>> Anyone please let me know whether any metallic nanoparticle
>>>>>>> with a
>>>>>>>
>>>>>> definite size
>>>>>
>>>>>> can have the same emission peak as its excitation peak???
>>>>>>>
>>>>>>> Thanks in advance
>>>>>>>
>>>>>>> Charu Tanwar
>>>>>>> Imaging Specialist
>>>>>>> Advanced Instrumentation Research Facility
>>>>>>> Jawaharlal Nehru University
>>>>>>> New Delhi
>>>>>>> India.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>>> 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: 91-22-2280-4610
>>>>> alternate e-mail: [log in to unmask]
>>>>> url: biophotonics.wetpaint.com
>>>>>
>>>>>
>>>> -- Mag. Johannes-P. KOCHDepartment of Biochemistry and Cell Biology
>>>>
>>>> MFPL, University of Vienna
>>>> Dr. Bohrgasse 9/5
>>>> A-1030 Vienna
>>>> Austria
>>>>
>>>> phone: 0043 1 4277 52809
>>>> fax: 0043 1 4277 9528
>>>>
>>>> mail to: [log in to unmask]
>>>>
>>>>
>>>>
>>>>
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