I need an optical FIR for experiment. where can i buy this kind of product? Thanks!
optical FIR product
Started by ●December 2, 2009
Reply by ●December 2, 20092009-12-02
gravelhe wrote:> I need an optical FIR for experiment. where can i buy this kind of product? > Thanks!Describe the experiment. -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●December 2, 20092009-12-02
On Dec 2, 7:59�am, "gravelhe" <grave...@gmail.com> wrote:> I need an optical FIR for experiment. where can i buy this kind of product? > Thanks!The hardware store. Get a piece of glass. Let the light reflect off of both the 1st and 2nd surface and interfere together. This is a simple comb filter. You may want to look it up under its fancier names like etalon or a Fabry- Perot interferometer. I assume you have a monochromatic light source. As Jerry asks, what kind of experiment do you need to do? Clay
Reply by ●December 3, 20092009-12-03
>On Dec 2, 7:59=A0am, "gravelhe" <grave...@gmail.com> wrote: >> I need an optical FIR for experiment. where can i buy this kind ofproduc=>t? >> Thanks! > >The hardware store. Get a piece of glass. Let the light reflect off of >both the 1st and 2nd surface and interfere together. This is a simple >comb filter. You may want to look it up under its fancier names like >etalon or a Fabry- Perot interferometer. I assume you have a >monochromatic light source. > >As Jerry asks, what kind of experiment do you need to do? > >Clay > I need the optical transversal filter as an OCDMA Encoder/Decoder intime domain. Thanks
Reply by ●December 3, 20092009-12-03
On Dec 3, 12:32�am, "gravelhe" <grave...@gmail.com> wrote:> >On Dec 2, 7:59=A0am, "gravelhe" <grave...@gmail.com> wrote: > >> I need an optical FIR for experiment. where can i buy this kind of > produc= > >t? > >> Thanks! > > >The hardware store. Get a piece of glass. Let the light reflect off of > >both the 1st and 2nd surface and interfere together. This is a simple > >comb filter. You may want to look it up under its fancier names like > >etalon or a Fabry- Perot interferometer. I assume you have a > >monochromatic light source. > > >As Jerry asks, what kind of experiment do you need to do? > > >Clay > > I need the optical transversal filter as an OCDMA Encoder/Decoder in > > time domain. Thanks- Hide quoted text - > > - Show quoted text -Then the piece of glass suffices.
Reply by ●December 3, 20092009-12-03
Clay wrote:> On Dec 3, 12:32 am, "gravelhe" <grave...@gmail.com> wrote: >>> On Dec 2, 7:59=A0am, "gravelhe" <grave...@gmail.com> wrote: >>>> I need an optical FIR for experiment. where can i buy this kind of >> produc= >>> t? >>>> Thanks! >>> The hardware store. Get a piece of glass. Let the light reflect off of >>> both the 1st and 2nd surface and interfere together. This is a simple >>> comb filter. You may want to look it up under its fancier names like >>> etalon or a Fabry- Perot interferometer. I assume you have a >>> monochromatic light source. >>> As Jerry asks, what kind of experiment do you need to do? >>> Clay >>> I need the optical transversal filter as an OCDMA Encoder/Decoder in >> time domain. Thanks- Hide quoted text - >> >> - Show quoted text - > > Then the piece of glass suffices.Avoiding interference when summing the taps requires great -- probably unobtainable -- mechanical stability. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●December 3, 20092009-12-03
On Dec 3, 11:08�am, Jerry Avins <j...@ieee.org> wrote:> Clay wrote: > > On Dec 3, 12:32 am, "gravelhe" <grave...@gmail.com> wrote: > >>> On Dec 2, 7:59=A0am, "gravelhe" <grave...@gmail.com> wrote: > >>>> I need an optical FIR for experiment. where can i buy this kind of > >> produc= > >>> t? > >>>> Thanks! > >>> The hardware store. Get a piece of glass. Let the light reflect off of > >>> both the 1st and 2nd surface and interfere together. This is a simple > >>> comb filter. You may want to look it up under its fancier names like > >>> etalon or a Fabry- Perot interferometer. I assume you have a > >>> monochromatic light source. > >>> As Jerry asks, what kind of experiment do you need to do? > >>> Clay > >>> I need the optical transversal filter as an OCDMA Encoder/Decoder in > >> time domain. Thanks- Hide quoted text - > > >> - Show quoted text - > > > Then the piece of glass suffices. > > Avoiding interference when summing the taps requires great -- probably > unobtainable -- mechanical stability. > > JerryThe interference resulting from combining the taps is the point. The OP wants a time domain optical filter. I gave him a simple example. He still hasn't revealed a whole lot of detail in what he needs experimentally other than "time domain." He can "tune" this filter by changing the angle of incidence whereby effectively change the delay between the 1st and 2nd reflections. If he wants something more complex (more than 2 taps), he can get a hydrogen alpha filter or something similar. These are made with many layers. Plus it is easy enough to make holographic gratings where he can have a fair number of Bragg planes (each acting like a tap in and FIR filter) What is the OP really wanting? Clay
Reply by ●December 3, 20092009-12-03
Clay wrote:> On Dec 3, 11:08 am, Jerry Avins <j...@ieee.org> wrote: >> Clay wrote: >>> On Dec 3, 12:32 am, "gravelhe" <grave...@gmail.com> wrote: >>>>> On Dec 2, 7:59=A0am, "gravelhe" <grave...@gmail.com> wrote: >>>>>> I need an optical FIR for experiment. where can i buy this kind of >>>> produc= >>>>> t? >>>>>> Thanks! >>>>> The hardware store. Get a piece of glass. Let the light reflect off of >>>>> both the 1st and 2nd surface and interfere together. This is a simple >>>>> comb filter. You may want to look it up under its fancier names like >>>>> etalon or a Fabry- Perot interferometer. I assume you have a >>>>> monochromatic light source. >>>>> As Jerry asks, what kind of experiment do you need to do? >>>>> Clay >>>>> I need the optical transversal filter as an OCDMA Encoder/Decoder in >>>> time domain. Thanks- Hide quoted text - >>>> - Show quoted text - >>> Then the piece of glass suffices. >> Avoiding interference when summing the taps requires great -- probably >> unobtainable -- mechanical stability. >> >> Jerry > > The interference resulting from combining the taps is the point.Maintaining stable interference means keeping dimensions stable to about 60 nm. That's *hard!*> The OP wants a time domain optical filter. I gave him a simple example. > He still hasn't revealed a whole lot of detail in what he needs > experimentally other than "time domain." He can "tune" this filter by > changing the angle of incidence whereby effectively change the delay > between the 1st and 2nd reflections. If he wants something more > complex (more than 2 taps), he can get a hydrogen alpha filter or > something similar. These are made with many layers. Plus it is easy > enough to make holographic gratings where he can have a fair number of > Bragg planes (each acting like a tap in and FIR filter) What is the OP > really wanting?Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●December 3, 20092009-12-03
>On Dec 3, 11:08=A0am, Jerry Avins <j...@ieee.org> wrote: >> Clay wrote: >> > On Dec 3, 12:32 am, "gravelhe" <grave...@gmail.com> wrote: >> >>> On Dec 2, 7:59=3DA0am, "gravelhe" <grave...@gmail.com> wrote: >> >>>> I need an optical FIR for experiment. where can i buy this kindof>> >> produc=3D >> >>> t? >> >>>> Thanks! >> >>> The hardware store. Get a piece of glass. Let the light reflect offo=>f >> >>> both the 1st and 2nd surface and interfere together. This is asimple>> >>> comb filter. You may want to look it up under its fancier nameslike>> >>> etalon or a Fabry- Perot interferometer. I assume you have a >> >>> monochromatic light source. >> >>> As Jerry asks, what kind of experiment do you need to do? >> >>> Clay >> >>> I need the optical transversal filter as an OCDMA Encoder/Decoderin>> >> time domain. Thanks- Hide quoted text - >> >> >> - Show quoted text - >> >> > Then the piece of glass suffices. >> >> Avoiding interference when summing the taps requires great -- probably >> unobtainable -- mechanical stability. >> >> Jerry > > [...] >He >still hasn't revealed a whole lot of detail in what he needs >experimentally other than "time domain." > [...]I thought that initially. It turns out the first line of his response had an extra greater-than, so it was lumped into your response on Google, and it's therefore easy to miss: (part of your response, but not really) "I need the optical transversal filter as an OCDMA Encoder/Decoder in" (what you probably saw, and what I initially saw) "time domain. Thanks"
Reply by ●December 3, 20092009-12-03
On Dec 3, 12:07=A0pm, Jerry Avins <j...@ieee.org> wrote:> Clay wrote: > > On Dec 3, 11:08 am, Jerry Avins <j...@ieee.org> wrote: > >> Clay wrote: > >>> On Dec 3, 12:32 am, "gravelhe" <grave...@gmail.com> wrote: > >>>>> On Dec 2, 7:59=3DA0am, "gravelhe" <grave...@gmail.com> wrote: > >>>>>> I need an optical FIR for experiment. where can i buy this kind of > >>>> produc=3D > >>>>> t? > >>>>>> Thanks! > >>>>> The hardware store. Get a piece of glass. Let the light reflect off=of> >>>>> both the 1st and 2nd surface and interfere together. This is a simp=le> >>>>> comb filter. You may want to look it up under its fancier names lik=e> >>>>> etalon or a Fabry- Perot interferometer. I assume you have a > >>>>> monochromatic light source. > >>>>> As Jerry asks, what kind of experiment do you need to do? > >>>>> Clay > >>>>> I need the optical transversal filter as an OCDMA Encoder/Decoder i=n> >>>> time domain. Thanks- Hide quoted text - > >>>> - Show quoted text - > >>> Then the piece of glass suffices. > >> Avoiding interference when summing the taps requires great -- probably > >> unobtainable -- mechanical stability. > > >> Jerry > > > The interference resulting from combining the taps is the point. > > Maintaining stable interference means keeping dimensions stable to about > 60 nm. That's *hard!* > > > The OP wants a time domain optical filter. I gave him a simple example. > > He still hasn't revealed a whole lot of detail in what he needs > > experimentally other than "time domain." He can "tune" this filter by > > changing the angle of incidence whereby effectively change the delay > > between the 1st and 2nd reflections. If he wants something more > > complex (more than 2 taps), he can get a hydrogen alpha filter or > > something similar. These are made with many layers. Plus it is easy > > enough to make holographic gratings where he can have a fair number of > > Bragg planes (each acting like a tap in and FIR filter) What is the OP > > really wanting? > > Jerry > -- > Engineering is the art of making what you want from things you can get. > =AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF==AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF= =AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF=AF- Hide qu= oted text -> > - Show quoted text -Actually it is not as hard as you think. An optical table will easily achieve this. Back when I used to make holograms, I did this sort of thing often on a sand box table. Yeap it is a 4 by 8 foot table (also 1 foot deep) filled with 2000lbs of sand. The optics are mounted onto pieces of PVC pipe stuck into the sand. You can easily adjust such optics. I would often set up a Michelson interferometer just to see how stable things are. Certainly if the heat or AC is blasting you will have problems. If one of my cats walked across the floor, the observed fringes would show the cat's walking! I would sometimes expose holograms upwards of 5 minutes on such a table. The shutter for the laser beam used a VU meter with a hole drilled through it and an aluminum foil flag attached to the needle. A little current through the meter would move the flag out of the beam. Clay
