As light is a wave, it travels in an oscillating pattern:

 | _     _     _     _     _     _     _     _    
 |/_\ _ /_\___/_\ _ /_\___/_\ _ /_\___/_\ _ /_\___
 |   \_/   \_/   \_/   \_/   \_/   \_/   \_/   \_/

In my understanding, if you decrease the amplitude, the oscillation will tend to straighten out. What if you manage to straighten it out completely, i.e. make photons move completely straight (see below)?

Is this possible?

What will its properties be?

Note: My theory on how to do this (impractical/impossible)-- You first cool down the photon to 0K. This will cease all oscillations, then somehow apply a force. Does this make any sense? Are there any better theories?

  • $\begingroup$ To speak of amplitudes of a photon is tricky. In classical optics, there are many uses but in quantum physics, amplitude does not have a well defined meaning. $\endgroup$ – Horus Mar 7 '16 at 14:58
  • $\begingroup$ temperature of a photon is some way unsettling. The photon is not a particle like an atom or a molecule. Photon is a packet of energy. Photon is a term coined by Einstein for this photoelectric effect. Photon also contains electric and magnetic field have you considered that? $\endgroup$ – Vinay5forPrime Mar 7 '16 at 15:06
  • $\begingroup$ @Vinay5forPrime The unsettling thing is not that photons are "not particles". The unsettling thing is talking about the temperature of a single particle in a definite state. Temperatures are ensemble properties. A photon gas in an evacuated cavity will have a well defined temperature (namely, the temperature of the walls of the cavity). $\endgroup$ – Sebastian Riese Mar 7 '16 at 16:21

A photon doesn't oscillate, and it travels in a straight line.

The classical electromagnetic field oscillates (with the electric and magnetic components perpendicular to each other), and the amplitude corresponds to the intensity of the radiation. Nothing is following the sinusoidal path you have drawn. To have zero amplitude, you simple have zero intensity of radiation. I.e. no radiation at all. The absence of any electromagnetic radiation.

From a photon-based perspective, the EM field is a property of a collection of photons, rather than a single photon. Talking about its amplitude doesn't really mean anything when you get down to individual photons. But if you take what the wave amplitude corresponds to classically, then the limit of the amplitude being zero corresponds to having no photons.

  • $\begingroup$ Thank you. We had always been shown light as a wave so I had that misconception. $\endgroup$ – Srathi00 Mar 7 '16 at 15:17

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