Any device to measure frequency of photon?

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Discussion Overview

The discussion revolves around methods and devices to measure the frequency of photons, particularly in the context of visible light. Participants explore various techniques and instruments relevant to different regions of the electromagnetic spectrum.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that frequency is typically not measured directly; instead, wavelength or energy is measured, from which frequency can be calculated.
  • One participant mentions the use of a grating spectrometer as a common device for measuring wavelength.
  • Another participant proposes using an antenna to detect induced signals, particularly for RF frequencies.
  • It is noted that different methods are applicable for various frequency ranges, such as using resonance in antennas for frequencies up to ~1THz and measuring energy for higher frequencies.
  • One participant highlights the use of single crystal diffraction for measuring wavelengths in the range of ~2 keV to 200 keV, suggesting that frequency is less commonly discussed in that context.
  • A participant reiterates the use of prisms or diffraction gratings for approximating the frequency of visible light photons and mentions the need for a spectrometer for precise measurements.
  • There is a light-hearted exchange regarding the size and types of spectrometers, including Fabry Perot and pushbroom spectrometers.

Areas of Agreement / Disagreement

Participants express a range of views on the best methods for measuring photon frequency, with no clear consensus on a single approach. Multiple competing methods and instruments are discussed, indicating a lack of agreement on a definitive solution.

Contextual Notes

Participants mention various frequency ranges and corresponding measurement techniques, but the discussion does not resolve the limitations or assumptions inherent in each method.

oem7110
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Visible light, like sunlight, consists of photons. Each photon has a level of energy (radiant energy) directly proportional to its frequency. Does anyone have any suggestions on any device to measure the frequency of Photon?
Thanks in advance for any suggestions
 
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One usually does not measure the frequency, but the wavelength. The most common device to do this is a grating spectrometer.

http://en.wikipedia.org/wiki/Spectrometer

Alternatively, you could try to measure the energy, e.g. via the photoelectric effect.
 
One normally measures their energy or wavelength and then calculates the frequency.
 
One can also use an antenna and look at the induced signal. This is what is often used to measure the RF frequency in cavities and accelerating structures. Something like a pick-up loop would do the job.

Zz.
 
Short version:

For frequencies up to ~100MHz (wavelength ~3m): just measure the electric field over time (frequency detection)
For frequencies up to ~1THz (wavelength ~30µm): Use resonance in antennas or circuits (wavelength detection)
For frequencies up to ~0.3PHz (wavelength ~100nm, energy ~10 eV): Use lenses or diffraction gratings (wavelength detection)
For higher frequencies: Measure the energy of the photons

The numbers are not hard limits, of course. They are just there to indicate different regions in the electromagnetic spectrum, where different detection methods are used.
 
and above ~2 keV up to 200 keV or so, use single crystal diffraction to determine the wavelength, as (more precise) alternative to measuring the energy. In that range nobody talks about frequency anymore.
 
oem7110 said:
Visible light, like sunlight, consists of photons. Each photon has a level of energy (radiant energy) directly proportional to its frequency. Does anyone have any suggestions on any device to measure the frequency of Photon?
Thanks in advance for any suggestions

If you wanted to know the approximate frequency of a visible light photon you could use a prism or diffraction grating to spread the light out (like in a rainbow). Then you would use this table from the below Wiki page to find the frequency band. If you needed a really precise frequency measurement you would need a "spectrometer". You can google that, if you want to.

Color Frequency Wavelength

violet 668–789 THz 380–450 nm
blue 631–668 THz 450–475 nm
cyan 606–630 THz 476–495 nm
green 526–606 THz 495–570 nm
yellow 508–526 THz 570–590 nm
orange 484–508 THz 590–620 nm
red 400–484 THz 620–750 nm

By the way, THz stands for "TeraHertz" and nm stands for "nanometers"
http://en.wikipedia.org/wiki/Visible_spectrum
 
How big is *your* spectrometer? :p

Yeah, lots of spectrometers: Fabry Perot, pushbroom, and others that are (in my mind) mostly extensions of these two.
 

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