Shooting photons 1 per second?

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Discussion Overview

The discussion revolves around the feasibility and mechanisms of generating single photons, particularly in the context of experimental setups. Participants explore the nature of photons, their emission, and the implications of quantum mechanics on these processes.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants express confusion about how a machine can emit one photon at a time, given the complexities surrounding the nature of photons.
  • Others argue that photons are well-defined within quantum electrodynamics, suggesting that the mystery surrounding them may be overstated.
  • A participant proposes that generating one photon per second on average is feasible, but emphasizes the randomness of photon arrival times.
  • Some mention specific setups, such as microspheres and quantum dots, that can control photon emission on demand.
  • There is a request for elaboration on how single-photon emitters work, particularly regarding the excitation processes involved.
  • Concerns are raised about the potential for multiple excitations during the pumping process, questioning the mechanisms that ensure single photon emission.
  • Participants share resources and references related to single-photon emitters and their applications.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the understanding of photons and the methods for their emission. There is no consensus on the mechanisms or the implications of photon emission processes.

Contextual Notes

Participants note limitations in understanding the excitation processes and the conditions under which single photons are emitted, highlighting the complexity of the topic.

Who May Find This Useful

This discussion may be of interest to those studying quantum optics, experimental physics, and anyone curious about the nature of light and photon emission technologies.

pivoxa15
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We might set up an experiment at University shooting photons one per second through slits. I think this experiment was done long ago and proved that light was a wave that was everywhere in that the photon seem to trave through both slits at the same time.

But I read in the Halliday, Resnick and Walker textbook that we still do not know a lot about the photon. So my question is how can a machine shoot out 1 photon at a time?

A photon is not matter so it does not have size or mass. How do we know that the machine is shooting out 1 photon if the photon itself is a mystery?

Thanks
 
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pivoxa15 said:
But I read in the Halliday, Resnick and Walker textbook that we still do not know a lot about the photon. So my question is how can a machine shoot out 1 photon at a time?

A photon is not matter so it does not have size or mass. How do we know that the machine is shooting out 1 photon if the photon itself is a mystery?

First of all, the photon is not such a big mystery (well, to some, it is :smile:). It is a relatively well-defined concept in a theory called quantum electrodynamics. So I don't know where H&R get their statement from! Maybe they just wanted to say that at the level of education they work (freshmen?) usually students don't know a lot about photons ?
Hey, this year, the guy who wrote down the entire theoretical framework for optical photons just got the Nobel prize. And he didn't invent the theory, (which was older) he just worked out the framework for optics!

However, to construct a machine that "sends out 1 photon per second" is going to be another piece of cake. I can think of 2 ways: sending out one photon per second ON AVERAGE (meaning, in 1000 seconds, the machine shot out about 1000 photons) is not difficult to do: take a light bulb, and calculate the thickness of the absorber needed. But the photons will arrive randomly.
I could also think of a more pulsed source, which shoots out regularly (every second) an attenuated light pulse, but the pulse will then contain 0, 1 or 2 or 3 photons. No way to let you have exactly ONE photon exactly every second.

cheers,
Patrick.
 
There are some setups in which you can control photon emission in order to produce photon on demand. May be, the mode I which this photon goes out is not so well determined. Look up microspheres, quantum dots and photon on demand. Probably you'll find it.

Best Regards

DaTario
 
DaTario said:
There are some setups in which you can control photon emission in order to produce photon on demand.

Could you elaborate ? I've indeed vaguely read about having something like an excited atom in a cavity ready to be "triggered" but I'd like to learn more about it.
 
An electrically driven single-photon emitter:
http://www.photonics.com/spectra/tech/XQ/ASP/techid.1353/QX/read.htm
http://www.mqc2.it/MQC204/Stevenson.pdf

Single photon emitters from pyramidal quantum dots:
http://nccr-qp.epfl.ch/webdav/site/nccr-qp/shared/import/migration/Project02b-3b.pdf

Enhanced single-photon emission from a quantum dot in a micropost microcavity:
http://www.stanford.edu/group/nqp/jv_files/papers/single_photons_APL_May03.pdf

Quantum Dots Emit Single Photons at High Temperatures:
http://oemagazine.com/fromTheMagazine/may04/pdf/eyeontech.pdf All the above, Microspheres, Quantum dots, pyramids and posts:
http://www.its.caltech.edu/~mankei/ee150sp03/qdots.ppt Regards, Hans.
 
Last edited by a moderator:
Hans de Vries said:
An electrically driven single-photon emitter:
http://www.photonics.com/spectra/tech/XQ/ASP/techid.1353/QX/read.htm
http://www.mqc2.it/MQC204/Stevenson.pdf

Single photon emitters from pyramidal quantum dots:
http://nccr-qp.epfl.ch/webdav/site/nccr-qp/shared/import/migration/Project02b-3b.pdf

Enhanced single-photon emission from a quantum dot in a micropost microcavity:
http://www.stanford.edu/group/nqp/jv_files/papers/single_photons_APL_May03.pdf

Quantum Dots Emit Single Photons at High Temperatures:
http://oemagazine.com/fromTheMagazine/may04/pdf/eyeontech.pdf


All the above, Microspheres, Quantum dots, pyramids and posts:
http://www.its.caltech.edu/~mankei/ee150sp03/qdots.ppt


Regards, Hans.


Thanks a lot ! I learned something new here.
However, there's one thing that bugs me: how come that the pumping doesn't induce several down-up-down transitions ?
 
Last edited by a moderator:
vanesch said:
Thanks a lot ! I learned something new here.
However, there's one thing that bugs me: how come that the pumping doesn't induce several down-up-down transitions ?
They talk about single photons from single exitations, that is, single electron hole pairs.


Regards, Hans

BTW: I've just received my copy of "Optical Coherence and Quantum Optics"
from Mandel and Wolf.
https://www.amazon.com/gp/product/0521417112/?tag=pfamazon01-20

Partly because of Glaubers Nobel price (Leonard Mandel is praised in
the Nobel price text for carrying Glaubers work further) and partly
because of our friend nightlight who claimed that the knowledge of
Glaubers work was mandadory for interpreting the results of:
"Observing the quantum behavior of light in an undergraduate laboratory"
http://marcus.whitman.edu/~beckmk/QM/grangier/Thorn_ajp.pdf

The latter fortunately isn't true (it wouldn't be an undergraduate
experiment) The math used for the experiment is rather simple.
 
Last edited by a moderator:
Hans de Vries said:
They talk about single photons from single exitations, that is, single electron hole pairs.

Yes, I understand that. What I don't understand, is why this single pair, during pumping, doesn't get excited, emits, gets excited again, emits again...
Because the same mechanism that is responsible for the exciting should also be responsible for stimulated emission.

BTW: I've just received my copy of "Optical Coherence and Quantum Optics"
from Mandel and Evans.
https://www.amazon.com/gp/product/0521417112/?tag=pfamazon01-20

It's a great book I have the impression. I read parts of it, but far from everything. I'd like to study it in detail one day...

cheers,
Patrick.
 
vanesch said:
It's a great book I have the impression. I read parts of it, but far from everything. I'd like to study it in detail one day...
It's almost 1200 pages :eek:. More a book to pick interesting topics from
instead of working your way through from beginning to end... :smile:


Regards, Hans
 
  • #10
Hans de Vries said:
It's almost 1200 pages :eek:. More a book to pick interesting topics from
instead of working your way through from beginning to end... :smile:
Regards, Hans

Yes, that's what I tried to do too, but it "builds up". You need to read quite a bit from previous chapters to even know what the next chapter is talking about. Happily, the first part is rather classical optics.
 

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