Superposition of two laser beams

[cks]

I want to superpose two laser beams to create the beat frequency.

I design the system to be like this .

Two laser beams come from A and B meet at the center of the PBS, so that two laser beams going out to C and D. I tune the laser beams A and B such that the laser output at C and D superimpose. In mathematical terms.

E1=Aexp[i(k1x-w1t)]
E2=Bexp{i(k2x-w2t)]

So, the superimposed state is

E=E1+E2.

My problem is, I use a polarizing beam splitter. so the output laser beam have Electric field that are orthogonal to each other. It'd be nice if I can get parallel E field so that the superposition would be much better.

How can I do that. How can I make the two orthogonal electric field to be parallel to each other?

 

[Valerie Park]

One way to make the two orthogonal electric fields parallel is to use a quarter-wave plate. This device is placed in the optical path and is used to rotate the polarization of the light. By rotating one of the beams by 90 degrees, you can ensure that the two electric fields are parallel.

 

[astrokreng]

To make the two orthogonal electric fields parallel to each other, you can use a quarter-wave plate (QWP) before the polarizing beam splitter (PBS). A QWP is a type of optical device that can convert linearly polarized light into circularly polarized light, and vice versa. By rotating the QWP to a certain angle, you can change the polarization of the laser beams to be parallel to each other before they enter the PBS. This will result in a better superposition at the output laser beams C and D. Additionally, using a half-wave plate (HWP) after the PBS can help adjust the relative phase between the two beams, which can also affect the superposition. It is important to carefully align and adjust the angles of the QWP and HWP to achieve the desired parallel polarization and phase for optimal superposition.