notch dichro=?utf-8?Q?=C3=AFc?= filter: does it exist?

[lechristophe]

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Hi,  

On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.

On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?

Thanks for your help,

Christophe

--
Christophe Leterrier
Postdoc
INSERM UMR641 // Ionic channels Lab
IFR Jean Roche, Mediterranée University
Marseille, France
http://www.cleterrier.net

[Kenton]

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Hi

I'm not sure I understand why you have to notch out the 491 from the lamp? I am assuming you want both the laser and the lamp light travelling the same route, and you are therefore just combining the beams?
The cheapest option is a broad spectrum beam splitter (a % silvered mirror) which will lose some of your light but you probably have excess anyway.
Otherwise you think you want a prism to combine the paths.

Sorry if I have misunderstood

Regards
Kenton


Dr Kenton Arkill
MVRL
Southwell St.
Bristol
BS2 8EJ
Office Tel. [phone]

THE BIG BANG THEORY: THE PHYSICS IS THEORETICAL BUT THE FUN IS REAL

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Christophe Leterrier
Sent: 30 November 2011 13:33
To: [hidden email]
Subject: notch dichroïc filter: does it exist?

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Hi,  

On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.

On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?

Thanks for your help,

Christophe

--
Christophe Leterrier
Postdoc
INSERM UMR641 // Ionic channels Lab
IFR Jean Roche, Mediterranée University
Marseille, France
http://www.cleterrier.net

[John Oreopoulos]

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Christophe, it's a good question. I'm not sure why there are so few "notch dichroic" filters, but I imagine it is because the filter companies don't get a lot of requests for optics like that. Think about it, the dichroics are usually intended to pass broadband light (usually fluorescence) to a detector, and the idea is that you would have also used an exciter and emission filter (positioned normal to the direction of light) to pass and block the laser light respectively.

Dichroic mirrors are used in laser engines to combine laser beams into one light path, but long pass and short pass mirrors can be used in succession if your arrange your lasers in increasing or decreasing wavelengths, so you don't need a notch filter here either.

Having said that, you can use a notch filter intended for normal incidence of light at some non-zero incident angle, but the position of the notch band with shift up or down the spectrum depending on how you turn it, and the transmission efficiency will lower. There are some newer filters that actually are intended for variable incident angles of light, though. For example, you could use a filter like this from Semrock (no commercial interest):

http://www.semrock.com/FilterDetails.aspx?id=TBP02-440/16-25x36

I think Chroma and Omega Optical (no commercial interest) might also make something similar. Turn this filter about 45 or 50 degrees, and arrange your light sources such that the arc lamp reflects off the mirror (instead of transmitting) and position your laser so that it transmits straight through. I think this would do what you want it to do.

John Oreopoulos
Research Assistant
Spectral Applied Research
Richmond Hill, Ontario
Canada
www.spectral.ca


On 2011-11-30, at 8:32 AM, Christophe Leterrier wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi,  
>
> On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.
>
> On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?
>
> Thanks for your help,
>
> Christophe
>
> --
> Christophe Leterrier
> Postdoc
> INSERM UMR641 // Ionic channels Lab
> IFR Jean Roche, Mediterranée University
> Marseille, France
> http://www.cleterrier.net

[Sebastian Rhode]

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Hi,

durinh my time when I was responsible for the development of the cell FRAP
system from Olympus I request such Notch Dichroics from Semrock for various
laser lines. For instance I requested a filter which is suitable for 340/380
Excitation (Ca-Imaging), reflects a 405nm laser for FRAP, PhotoSwitching and
Photoactivation. Next there was an emmsion window (420-465nm) and again a
reflection band for a 473nm (for GFP bleaching) laser followed by emission
window from 480-700nm.
Unfortunately the complete R&D facilty in Munich was closed down, before I
could test it, but if you ask them, they will make it for you. But be
prepared for the pricing ...

Cheers, Sebi

[lechristophe]

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Hi John,

I think the best option I found for the moment is to use a multiband dichroic with a second band that is off my imaging window (for live cell experiments I use GFP and mCherry). So a 497/661 dichroic like this one will be OK:
http://www.semrock.com/FilterDetails.aspx?id=FF497/661-Di01-25x36
(plus it's on sale!)

What I don't know is why those dichroics don't exist with a single-wavelength notch (imagine the same dichroic but without the 661 dip). There is only one single-notch dichroic in the Semrock catalog but it is at 1064 nm.

Christophe  


Le mercredi 30 novembre 2011 à 15:42, John Oreopoulos a écrit :

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>  
> Christophe, it's a good question. I'm not sure why there are so few "notch dichroic" filters, but I imagine it is because the filter companies don't get a lot of requests for optics like that. Think about it, the dichroics are usually intended to pass broadband light (usually fluorescence) to a detector, and the idea is that you would have also used an exciter and emission filter (positioned normal to the direction of light) to pass and block the laser light respectively.  
>  
> Dichroic mirrors are used in laser engines to combine laser beams into one light path, but long pass and short pass mirrors can be used in succession if your arrange your lasers in increasing or decreasing wavelengths, so you don't need a notch filter here either.
>  
> Having said that, you can use a notch filter intended for normal incidence of light at some non-zero incident angle, but the position of the notch band with shift up or down the spectrum depending on how you turn it, and the transmission efficiency will lower. There are some newer filters that actually are intended for variable incident angles of light, though. For example, you could use a filter like this from Semrock (no commercial interest):
>  
> http://www.semrock.com/FilterDetails.aspx?id=TBP02-440/16-25x36
>  
> I think Chroma and Omega Optical (no commercial interest) might also make something similar. Turn this filter about 45 or 50 degrees, and arrange your light sources such that the arc lamp reflects off the mirror (instead of transmitting) and position your laser so that it transmits straight through. I think this would do what you want it to do.
>  
> John Oreopoulos
> Research Assistant
> Spectral Applied Research
> Richmond Hill, Ontario
> Canada
> www.spectral.ca (http://www.spectral.ca)
>  
>  
> On 2011-11-30, at 8:32 AM, Christophe Leterrier wrote:
>  
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > *****
> >  
> > Hi,  
> >  
> > On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.
> >  
> > On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?
> >  
> > Thanks for your help,
> >  
> > Christophe
> >  
> > --
> > Christophe Leterrier
> > Postdoc
> > INSERM UMR641 // Ionic channels Lab
> > IFR Jean Roche, Mediterranée University
> > Marseille, France
> > http://www.cleterrier.net
> >  
>  
>  
>  

[lechristophe]

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Hi Kenton,

The thing is, I don't want to loose any of the FRAP laser light (because less power means longer bleaching time and less rigourous fluorescence recovery analysis in the case of fast fluorophore exchange), and I already loose 50% of the HBO light due to another combining with a TIRF laser downstream (combined using a polarizing mirror). Plus I'm using either an HBO or a fast-switching DG4 xenon lamp which is already quite dim.

So I figured that spectrally filtering the laser line out of the lamp spectra would be more efficient (I'll loose some of the lamp light, it will depend on the width of the notch, and will keep 100% of the laser) than a 50/50 or so splitter. Exactly how much of the lamp excitation I will loose as a function of the fluorophore (here GFP) and spectral profile of the notch would be an interesting thing to estimate though.

Christophe


Le mercredi 30 novembre 2011 à 15:16, Kenton Arkill a écrit :

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>  
> Hi
>  
> I'm not sure I understand why you have to notch out the 491 from the lamp? I am assuming you want both the laser and the lamp light travelling the same route, and you are therefore just combining the beams?
> The cheapest option is a broad spectrum beam splitter (a % silvered mirror) which will lose some of your light but you probably have excess anyway.
> Otherwise you think you want a prism to combine the paths.
>  
> Sorry if I have misunderstood
>  
> Regards
> Kenton
>  
>  
> Dr Kenton Arkill
> MVRL
> Southwell St.
> Bristol
> BS2 8EJ
> Office Tel. [phone]
>  
> THE BIG BANG THEORY: THE PHYSICS IS THEORETICAL BUT THE FUN IS REAL
>  
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Christophe Leterrier
> Sent: 30 November 2011 13:33
> To: [hidden email] (mailto:[hidden email])
> Subject: notch dichroïc filter: does it exist?
>  
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>  
> Hi,  
>  
> On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.
>  
> On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?
>  
> Thanks for your help,
>  
> Christophe
>  
> --
> Christophe Leterrier
> Postdoc
> INSERM UMR641 // Ionic channels Lab
> IFR Jean Roche, Mediterranée University
> Marseille, France
> http://www.cleterrier.net
>  
>  

[David Baddeley]

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One of the issues with making a notch dichroic (or tilting an existing notch to 45 degrees) is that s and p polarisations behave differently at non-normal incidence. If you do go the tilting route, you might need to take a little care with the polarisation of your laser (if I remember rightly p retains it's shape whereas s will be broadened). 

Depending on how you do your FRAP, might be able to put a patterned mirror in a Fourier plane. If you have a FRAP beam with a reasonably broad waist, you could potentially get away with reflecting it from the centre of your mirror whilst letting the arc-lamp light round the sides. 

cheers,
David


________________________________
 From: Christophe Leterrier <[hidden email]>
To: [hidden email]
Sent: Thursday, 1 December 2011 5:18 AM
Subject: Re: notch dichroïc filter: does it exist?
 
*****
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Hi Kenton,

The thing is, I don't want to loose any of the FRAP laser light (because less power means longer bleaching time and less rigourous fluorescence recovery analysis in the case of fast fluorophore exchange), and I already loose 50% of the HBO light due to another combining with a TIRF laser downstream (combined using a polarizing mirror). Plus I'm using either an HBO or a fast-switching DG4 xenon lamp which is already quite dim.

So I figured that spectrally filtering the laser line out of the lamp spectra would be more efficient (I'll loose some of the lamp light, it will depend on the width of the notch, and will keep 100% of the laser) than a 50/50 or so splitter. Exactly how much of the lamp excitation I will loose as a function of the fluorophore (here GFP) and spectral profile of the notch would be an interesting thing to estimate though.

Christophe


Le mercredi 30 novembre 2011 à 15:16, Kenton Arkill a écrit :

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
> 
> Hi
> 
> I'm not sure I understand why you have to notch out the 491 from the lamp? I am assuming you want both the laser and the lamp light travelling the same route, and you are therefore just combining the beams?
> The cheapest option is a broad spectrum beam splitter (a % silvered mirror) which will lose some of your light but you probably have excess anyway.
> Otherwise you think you want a prism to combine the paths.
> 
> Sorry if I have misunderstood
> 
> Regards
> Kenton
> 
> 
> Dr Kenton Arkill
> MVRL
> Southwell St.
> Bristol
> BS2 8EJ
> Office Tel. [phone]
> 
> THE BIG BANG THEORY: THE PHYSICS IS THEORETICAL BUT THE FUN IS REAL
> 
> -----Original Message-----
> From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Christophe Leterrier
> Sent: 30 November 2011 13:33
> To: [hidden email] (mailto:[hidden email])
> Subject: notch dichroïc filter: does it exist?
> 
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
> 
> Hi, 
> 
> On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber coupling) with an HBO xenon lamp (direct mount) on the back of my scope. The way things are arranged, I need to put a 45° dichroic mirror so that the lamp light will go through the mirror into the scope and the laser light will be reflected into the scope. So I'm looking for a dichroic mirror that would transmit everything (from 400 to 750) but a small window arround 491 nm. The window has to be narrow so that I don't loose too much GFP excitation light from the lamp. Is that kind of dichroïc available? I could'nt find one browsing Chroma or Semrock offers. Of course there is the option of having a custom one made, but I was wondering if someone had a link to an existing offer.
> 
> On a related note, I found lots of notch filters but not a lot of notch dichroics. What is the difference between a simple filter and a dichroic? What happens to the blocked light in the case of a filter, isn't it also reflected like for a dichroic?
> 
> Thanks for your help,
> 
> Christophe
> 
> --
> Christophe Leterrier
> Postdoc
> INSERM UMR641 // Ionic channels Lab
> IFR Jean Roche, Mediterranée University
> Marseille, France
> http://www.cleterrier.net
> 
> 

[Craig Brideau]

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I will actually be covering polarization issues for my poster at this
year's Photonics West (BIOS).  Stop by the poster session if you are
interested!

Craig



On Thu, Dec 1, 2011 at 1:37 PM, David Baddeley
<[hidden email]>wrote:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> One of the issues with making a notch dichroic (or tilting an existing
> notch to 45 degrees) is that s and p polarisations behave differently at
> non-normal incidence. If you do go the tilting route, you might need to
> take a little care with the polarisation of your laser (if I remember
> rightly p retains it's shape whereas s will be broadened).
>
> Depending on how you do your FRAP, might be able to put a patterned mirror
> in a Fourier plane. If you have a FRAP beam with a reasonably broad waist,
> you could potentially get away with reflecting it from the centre of your
> mirror whilst letting the arc-lamp light round the sides.
>
> cheers,
> David
>
>
> ________________________________
>  From: Christophe Leterrier <[hidden email]>
> To: [hidden email]
> Sent: Thursday, 1 December 2011 5:18 AM
> Subject: Re: notch dichroïc filter: does it exist?
>
> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> *****
>
> Hi Kenton,
>
> The thing is, I don't want to loose any of the FRAP laser light (because
> less power means longer bleaching time and less rigourous fluorescence
> recovery analysis in the case of fast fluorophore exchange), and I already
> loose 50% of the HBO light due to another combining with a TIRF laser
> downstream (combined using a polarizing mirror). Plus I'm using either an
> HBO or a fast-switching DG4 xenon lamp which is already quite dim.
>
> So I figured that spectrally filtering the laser line out of the lamp
> spectra would be more efficient (I'll loose some of the lamp light, it will
> depend on the width of the notch, and will keep 100% of the laser) than a
> 50/50 or so splitter. Exactly how much of the lamp excitation I will loose
> as a function of the fluorophore (here GFP) and spectral profile of the
> notch would be an interesting thing to estimate though.
>
> Christophe
>
>
> Le mercredi 30 novembre 2011 à 15:16, Kenton Arkill a écrit :
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > *****
> >
> > Hi
> >
> > I'm not sure I understand why you have to notch out the 491 from the
> lamp? I am assuming you want both the laser and the lamp light travelling
> the same route, and you are therefore just combining the beams?
> > The cheapest option is a broad spectrum beam splitter (a % silvered
> mirror) which will lose some of your light but you probably have excess
> anyway.
> > Otherwise you think you want a prism to combine the paths.
> >
> > Sorry if I have misunderstood
> >
> > Regards
> > Kenton
> >
> >
> > Dr Kenton Arkill
> > MVRL
> > Southwell St.
> > Bristol
> > BS2 8EJ
> > Office Tel. [phone]
> >
> > THE BIG BANG THEORY: THE PHYSICS IS THEORETICAL BUT THE FUN IS REAL
> >
> > -----Original Message-----
> > From: Confocal Microscopy List [mailto:[hidden email]]
> On Behalf Of Christophe Leterrier
> > Sent: 30 November 2011 13:33
> > To: [hidden email] (mailto:
> [hidden email])
> > Subject: notch dichroïc filter: does it exist?
> >
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > *****
> >
> > Hi,
> >
> > On a widefield/FRAP setup, I want to combine a laser at 491 nm (fiber
> coupling) with an HBO xenon lamp (direct mount) on the back of my scope.
> The way things are arranged, I need to put a 45° dichroic mirror so that
> the lamp light will go through the mirror into the scope and the laser
> light will be reflected into the scope. So I'm looking for a dichroic
> mirror that would transmit everything (from 400 to 750) but a small window
> arround 491 nm. The window has to be narrow so that I don't loose too much
> GFP excitation light from the lamp. Is that kind of dichroïc available? I
> could'nt find one browsing Chroma or Semrock offers. Of course there is the
> option of having a custom one made, but I was wondering if someone had a
> link to an existing offer.
> >
> > On a related note, I found lots of notch filters but not a lot of notch
> dichroics. What is the difference between a simple filter and a dichroic?
> What happens to the blocked light in the case of a filter, isn't it also
> reflected like for a dichroic?
> >
> > Thanks for your help,
> >
> > Christophe
> >
> > --
> > Christophe Leterrier
> > Postdoc
> > INSERM UMR641 // Ionic channels Lab
> > IFR Jean Roche, Mediterranée University
> > Marseille, France
> > http://www.cleterrier.net
> >
> >
>