Any real EM oscillarion if superposition of waves of many frequencies, oscillating in multiple planes, or changing planes of polarization irratically. The waves thus described have discontinuities (in terms of sudden 'jumps and falls' of EM fields) , and the phase relation between oscillation along direction of propagation is randomized every short distance. One may read about spatial/transverse coherency and temporal/longitudinal coherency of EM waves.

BTW, any oscillation in 3D can be broken into two oscillations working in mutually perpendicular directions, and any periodic function can be written as sum of sines and cosines using fourier transform. almost all EM oscillations are vibratory plus erratic in that sense, and the wave can be broken diown to two planes, and wave oscillation on the planes can be expresses as combination of constituent frequencies.

Sumit Bhowmick

In general, you are right but, I can of coarse chose any kind of EM-oscillation for the discussion above. So, I chose a perfect EM-wave.

I believe you are a bit too theoretical, in practice you can very well obtain a clean EM-wave having a perfect oscillation at one specific frequency.

JES

A laser is an amplifier, but an electromagnetic wave is not.

You are talking about the wave-particle duality in quantum mechanics. Photons are light and can be thought of as both waves and particles. Extensive literature is available on this topic.

Unfortunately, the mixing of light is a particle (a photon) or light is a wave (EM wave) is confusing and false physics. There are several experimental observations that reject the wave model of light AND several other experimental observations that reject the photon model of light. The challenge is to explain both types of observation with one model (either a wave model of the particle supporting experiments or a particle model of the wave supporting experiments such as interference). The wave-particle duality has been rejected by experiment (Afshar's experiment). The wave modelof light has been rejected by an interference experiment (the Hodge experiment which can be done with little investment - by amateurs

)Interference Experiment with a Transparent Mask Rejects Wave Models of Lght

Optics and photonics journal vol. 9, No. 6 jun 2019

https://www.scirp.org/journal/paperinformation.aspx?paperid=93056

https://doi.org/10.4236/opj.2019.96008

https://www.youtube.com/watch?v=qFDB-K_sSjU

https://www.youtube.com/watch?v=A07bogzzMEI )

Further, the Biot-Savart law for EM waves has been rejected, also by experiment.

Article Magnetostatics relation to gravity with experiment that reje...

https://www.youtube.com/watch?v=qFDB-K_sSjU&t=3s

Here, moving photons (particles) induce waves in a medium which are the EM part of the experiments. But the photons are particles, So particle AND wave in each of the experiments.

John Hodge - how does Biot-Savart law apply to EM waves. It is about a moving current of electrons and magnetostatics as far as I know.

Hiçbir zaman bir elektromanyetik dalga ortamın aynı olması şartıyla fotonun gösterdiği özelliği göstermez.

Nicholas Edward Schlotter

Moving electrons in a wire (read antenna) produces the EM wave. The model of the wave is an EM field where the ``M'' denoted magnetism. The STOE suggests the magnetic field causes the electric field. Some suggest the E causes the M. But either way, the field extends only perpendicular to the wire by the referenced experiment rather than the usual Maxwell's Equations interpretation. Further, the EM (radio signal) travels at the speed of light. Whereas the coulomb field travels much much faster than the speed of light as measured by de Sangro and others. The STOE solution to the theoretical issues is to have photons (particles) emitted as the antenna radiation and the coulomb field being an ether field. This also the solves the wave-particle interference vs particle experiments as the references describe.

John Hodge

You shouldn't think of interactions as some thing done by an exchange of particles. If its an exchange of particles then you should have a "delayed potential".

If you have no delay in potential then it must be an interaction between fields surrounding the participants. Like static EM-fields or gravitation.

JES

Stellan Gustafsson

I don't. Interaction is one thing CAUSES another to change. In the STOE, the photon causes a change in the plenum (spacetime, vacuum, zero point field, etc.) which then causes a force on another photon. Not exchange.

I will stay with Maxwell and quantum mechanics. John Hodge has an eclectic viewpoint and I will not debate right or wrong. However, a new student needs to learn accepted quantum mechanics before studying a controversial view. IMHO

A wave is a fiction, a collective effect visible in the macrocosm, while physically one has particles.

Do anyone no of the detection of a photon within an EM-wave?

I'm thinking of electrostatic platforms (used for ion sources in accelerators). If there were photons flying around they should have been detected by the sensible electronics on such platforms!?

JES

SG: QM does show that continuity experimentally does not exist, even though some opinions may diverge, reacting to bias, as in the famous ref.[6], published by Springer Verlag.

Now, the work at my profile in RG (where ref.[6] is cited) shows that continuity may exist in mathematics, but leads to wrong results. The wave-particle duality is a conundrum, waves only exist macroscopicallly as a collective effect. Microscopically, one has particles -- only. This is caused by Universality, as it is called in physics.

I hope to have clarified the text, after some useful feedback demonstrating the value of RG. The new text is at:

https://www.researchgate.net/publication/366124503/

Thank you.

In a coherent beam, such as from a microwave antenna, or a laser, the beam consists of photons each of which spreads over the entire beam, and have a length depending on the coherence time.

A photon will only be detected in one place, somewhere in its extent in time and space, at the particular detector it interacts with. This does not indicate the size of the photon.

Most light beams are incoherent and the photon size cannot be related to the size of the beam, and the photons may also be very short in length. There is a lot of maths to do with coherent and incoherent radiation, see for instance radiation statistics and the theory of coherence, e.g. Chapter 14 of Electromagnetic waves, 2nd Ed, Someda.

Malcolm White

microwave antenna and a Laser is not the same thing. In a Laser you have photons with the same wavelength and phase. They don't spread out within the beam. They travels parallel to each other without strong interaction leading to an almost parallel beam. This is completely different from an EM-wave which is spread out like a wave on the surface of water.

JES

A microwave beam will travel just as a laser does, and a laser just as a microwave beam does, if the microwave antenna is many many wavelengths wide, as the mirror for a laser is, or if the laser is passed through a few wavelength wide aperture. Gaussian beam optics, for instance, describes laser beams and microwave beams equally well, as does physical optics.

Microwave photons do not interact with each other, except in non-linear materials, which is just the same as laser photons.

Look up Gaussian beam optics. The maths for the fundamental mode is simple and the divergence of a laser beam or a microwave beam can be calculated easily, and is a direct consequence of the size of the aperture in wavelengths, not whether it is light or microwaves.

We normally see laser beams in the near-field, where the beam looks parallel (near the waist of a Gaussian beam). The beam starts to noticeably diverge at a distance equal to twice the width of the aperture, multiplied by the number of wavelengths across the aperture. When the wavelength is about a micron and the aperture diameter is 1 mm it doesn't start to diverge for 2 m, and the divergence is 1/1000 radians (1/number of wavelengths across the aperture), or about 1/16 degrees.

See https://www.rp-photonics.com/beam_divergence.html for instance.

A 1000 wavelength wide microwave antenna would have the same beamwidth (and would be 30 m wide!). The microwave beam would look substantially parallel for 30 to 60 km. SAR uses this to get synthetic narrow beams from tens of metres of satellite track to map the earth with the resolution given by the width of the synthetic beam