downconverting optical frequencies...
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From: glen herrmannsfeldt on 18 Jul 2010 22:09 steveu <steveu(a)n_o_s_p_a_m.coppice.org> wrote: (snip) > One crude downconvert with real world applications is to shine two lasers > on a silicon photosensor. I think most types of silicon sensor work OK for > this. The modes of a laser are typically hundreds of megahertz apart. If > you use gratings to pick out a single mode from each of the lasers, you > will see the difference frequency in the output of the sensor. I thought they used microwave mixer diodes, but maybe you don't need that to get 300MHz by now. There are diodes that go much faster than that, though. -- glen
From: Clay on 19 Jul 2010 10:08 On Jul 18, 9:41 am, "fisico32" <marcoscipioni1(a)n_o_s_p_a_m.gmail.com> wrote: > hello forum, > > I know that is it is possible to downconvert high frequencies to lower > frequencies.... > > what is the highest frequency we can downconvert and why? How is it done? > > ( I don't think the issue exists in the reverse direction: we can convert > any low frequency signal to a high frequency one) > > thanks > fisico32 How high do you want to go? Check out both the Compton and Inverse Compton scattering. http://en.wikipedia.org/wiki/Compton_scattering You can upconvert E-M radiation to make x-ray or gamma beams by upconverting uv light by ramming them head on into a electron stream (inverse compton effect). Optically heteodyning is done in the lab via nonlinear mixing. Just mix two high power laser beams in a crystal such as ammonium dihydron phospate. Clay
From: Vladimir Vassilevsky on 19 Jul 2010 11:50 fisico32 wrote: > hello forum, > > I know that is it is possible to downconvert high frequencies to lower > frequencies.... > > what is the highest frequency we can downconvert and why? ~1e35 Hz. Nothing higher then that had been discovered so far. > How is it done? All processes are nonlinear; they only seem to be linear because of the law of big numbers. > ( I don't think the issue exists in the reverse direction: we can convert > any low frequency signal to a high frequency one) > thanks > fisico32 I think you are Radium the Troll. VLV
From: Jerry Avins on 19 Jul 2010 12:46 On 7/19/2010 11:50 AM, Vladimir Vassilevsky wrote: ... > I think you are Radium the Troll. Radium >> Green Xenon Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
From: Tim Wescott on 19 Jul 2010 12:51
On 07/19/2010 07:08 AM, Clay wrote: > On Jul 18, 9:41 am, "fisico32"<marcoscipioni1(a)n_o_s_p_a_m.gmail.com> > wrote: >> hello forum, >> >> I know that is it is possible to downconvert high frequencies to lower >> frequencies.... >> >> what is the highest frequency we can downconvert and why? How is it done? >> >> ( I don't think the issue exists in the reverse direction: we can convert >> any low frequency signal to a high frequency one) >> >> thanks >> fisico32 > > How high do you want to go? Check out both the Compton and Inverse > Compton scattering. http://en.wikipedia.org/wiki/Compton_scattering > > > You can upconvert E-M radiation to make x-ray or gamma beams by > upconverting uv light by ramming them head on into a electron stream > (inverse compton effect). Does that result in light that is coherent to the source? I.e. is the amplitude of the light wave multiplied by some power function, or is the mechanism more like cyclotron radiation? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" was written for you. See details at http://www.wescottdesign.com/actfes/actfes.html |