waveguide

The flow is to modulate each wavelength individually, mux them together, send them through a single fiber or waveguide, and then demux them on the other side.

You can show classically, using Maxwell's equations, that the group velocity of a wave of light when confined to a waveguide is less than light in free space.

So the characteristics of the waveguide (such as the conductivity of the ground) influence the speed of propagation.

The effective output impedance of a transmission line depends on the fraction of wavelengths of waveguide transmit the wave.

The solution is to use a compression driver (CD) with a waveguide but mostly for aesthetic reasons, there are virtually no commercial speakers on the market that use CDs.

So there's limited commercial demand for waveguide modelling, and no demand at all for a full-fat 3D rendered synthesis engine.

So taking out the magnetron and putting a beamforming waveguide on it was a bad idea?

If there is a waveguide involved why does the headline talk about photons in free space?

The microwave ham radio contester guys seem to like horn antennas at that band so couple it into a moderately large waveguide and attach the (homemade) waveguide to a (homemade) horn antenna.

Even if it does act as a waveguide, it might make it safe enough.

It makes more sense to use waveguide models or procedural simulations, because they produce similar results for a tiny fraction of the cycles.

You can think of a waveguide as being a highly engineered mirror, really.

I guess that means somehow they construct photons in a "waveguide-like configuration" but in free space?

The title should be corrected to something truthful, like "Photons in waveguide-like configuration travel slower than light due to self-interference, as predicted".

These two contributions balance out and cause a "waveguide" where the light essentially travels along a narrow channel, allowing the focusing pulse to travel longer without as much spatial dispersion.

So, I do a little bit of related research in this area: This is typically called a "filament", a "plasma channel", and sometimes described as a waveguide.