How to determine the vector magnetic field, when emitting light?

Question

Electronics

Light is an electromagnetic field, as far as I understand. If we take an LED, for example, what device, device, etc.
one can determine the magnetic field vectors.
As I understand it (do not kick too much), if the gradient from the radiation that we see is taken, it can be decomposed into vectors through the nabla operator, and the rotor of this vector field should not be equal to zero, in theory.
I don’t know how to do this, but it’s interesting to the point of eerily - please help, maybe there is a picture or image somewhere.

Answer 1

Almost any light source emits unpolarized radiation - many waves with different field vectors, a chaotic set. In this chaos, there is no point in looking for field vectors.
But, having passed through the polarizer, only components of one direction of oscillation remain. It is agreed that polarization refers to the electric component of the field. Therefore, the magnetic field vector will be at an angle of 90 degrees to the polarization value.
In the opposite direction, it is also possible - if you have polarized radiation with an unknown polarization, then you just have to find the polarization value to determine the vectors. This can be done with a rotary polarizer - rotate it until the light begins to pass through it. This position will correspond to the value of polarization and the plane of oscillation of the vector of the electric component of light. Magnetic again will be at an angle of 90 degrees.