4 ms·

Keep dreaming. Electrons interact with each other, photons don't.

mensetmanusman 6y ago
Not directly, but you can do really clever things with nonlinearity, look at this recent development: https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320.php https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320... Essentially, if you trap a few photons in little resonator cavities that rely on mostly all of the electrons making up the cavity, the next set of photons can pass through the cavity without interaction. This means the light interacts with engineered electrons in a specific way to create an optical switch. This is a critical component of photonics on a chip, and was just demonstrated with Si (which is a requirement for something in the mid term).
- octoberfranklin 6y ago
  People have been doing "neat hacks" with nonlinear optics for a long time. None of it is remotely close to being usable as a photon-controlled photon gate. All-optical switching (i.e. photonic computing) is like fusion power generation. It's been "right around the corner" for 20 years, yet we never seem to round the bend. It is, however, great for physicists writing grant applications. > look at this recent development: https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320 https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320... This was on HN here: https://news.ycombinator.com/item?id=24997573 https://news.ycombinator.com/item?id=24997573 My response here: https://news.ycombinator.com/item?id=25012670 https://news.ycombinator.com/item?id=25012670 Summary: this is converting information from the photonic domain to the thermal domain. Heat diffuses very slowly; you won't be able to put a lot of these devices near each other and run them at usable speeds without them causing each other thermal interference.
nullc 6y ago
My green laser pointer would like to have a word with you.
- octoberfranklin 6y ago
  If I were made of photons it wouldn't be able to!
  - nullc 6y ago
    Of course it would: It's coherent light! [But seriously, the green light of a standard green laser pointer is generated from the non-linear interaction of pairs of 1064nm photons.]
    - octoberfranklin 6y ago
      > the green light of a standard green laser pointer is generated from the non-linear interaction of pairs of 1064nm photons. Um, no. It is caused by stimulated emission in the lasing medium, when electrons drop from a higher to lower energy level. Pairs of photons do not interact with each other. https://en.m.wikipedia.org/wiki/Laser_pumping https://en.m.wikipedia.org/wiki/Laser_pumping In rare situations you might have an ion or an entire atom changing energy levels. But never just a photon. https://en.m.wikipedia.org/wiki/Stimulated_emission https://en.m.wikipedia.org/wiki/Stimulated_emission If you don't believe that photons are bosons I don't think we're going to get anywhere with this discussion...
      - nullc 6y ago
        > It is caused by stimulated emission in the lasing medium, when electrons drop from a higher to lower energy level. In a typical green laser pointer a 1064nm light is produced via ordinary laser mechanisms, then 1064nm light is upconverted in a non-linear medium to 523nm. https://en.wikipedia.org/wiki/Second-harmonic_generation https://en.wikipedia.org/wiki/Second-harmonic_generation Yes, in a medium. You also don't see a lot of conventional computers constructed without semiconductors. :)

Not directly, but you can do really clever things with nonlinearity, look at this recent development: https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320.php https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320... Essentially, if you trap a few photons in little resonator cavities that rely on mostly all of the electrons making up the cavity, the next set of photons can pass through the cavity without interaction. This means the light interacts with engineered electrons in a specific way to create an optical switch. This is a critical component of photonics on a chip, and was just demonstrated with Si (which is a requirement for something in the mid term).

octoberfranklin 6y ago
People have been doing "neat hacks" with nonlinear optics for a long time. None of it is remotely close to being usable as a photon-controlled photon gate. All-optical switching (i.e. photonic computing) is like fusion power generation. It's been "right around the corner" for 20 years, yet we never seem to round the bend. It is, however, great for physicists writing grant applications. > look at this recent development: https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320 https://www.eurekalert.org/pub_releases/2020-11/ou-1ei110320... This was on HN here: https://news.ycombinator.com/item?id=24997573 https://news.ycombinator.com/item?id=24997573 My response here: https://news.ycombinator.com/item?id=25012670 https://news.ycombinator.com/item?id=25012670 Summary: this is converting information from the photonic domain to the thermal domain. Heat diffuses very slowly; you won't be able to put a lot of these devices near each other and run them at usable speeds without them causing each other thermal interference.

nullc 6y ago

My green laser pointer would like to have a word with you.

octoberfranklin 6y ago
If I were made of photons it wouldn't be able to!
- nullc 6y ago
  Of course it would: It's coherent light! [But seriously, the green light of a standard green laser pointer is generated from the non-linear interaction of pairs of 1064nm photons.]
  - octoberfranklin 6y ago
    > the green light of a standard green laser pointer is generated from the non-linear interaction of pairs of 1064nm photons. Um, no. It is caused by stimulated emission in the lasing medium, when electrons drop from a higher to lower energy level. Pairs of photons do not interact with each other. https://en.m.wikipedia.org/wiki/Laser_pumping https://en.m.wikipedia.org/wiki/Laser_pumping In rare situations you might have an ion or an entire atom changing energy levels. But never just a photon. https://en.m.wikipedia.org/wiki/Stimulated_emission https://en.m.wikipedia.org/wiki/Stimulated_emission If you don't believe that photons are bosons I don't think we're going to get anywhere with this discussion...
    - nullc 6y ago
      > It is caused by stimulated emission in the lasing medium, when electrons drop from a higher to lower energy level. In a typical green laser pointer a 1064nm light is produced via ordinary laser mechanisms, then 1064nm light is upconverted in a non-linear medium to 523nm. https://en.wikipedia.org/wiki/Second-harmonic_generation https://en.wikipedia.org/wiki/Second-harmonic_generation Yes, in a medium. You also don't see a lot of conventional computers constructed without semiconductors. :)