How a TFP (Thin Flim Polarizer) works?

[goodphy]

Hello.

I've been really curious about how TFP (Thin Flim Polarizer) works. I've searched TFP information through the Internet which tells that TFP utilizes Brewster's angle. This explains how the P-polarization transmits TFP with 100 % transmission, but I don't know how the S-polarization is filtered out as a high reflection. A Multi-layer dielectric coating on TFP substrate for a high reflection could be a solution, but...it could mean both P and S-polarizations are highly reflected at a TFP surface.

If the coating is precisely designed (in terms of refractive indices of coating materials and coating layer thicknesses) such that the P-polarization goes through every surfaces of coating layers and the TFP substrate at Brewster's angle, then the S-polarization is highly reflected while the P-polarization gets 100 % transmission. This is my TFP design principle, but...I'm not sure if this is a usual way of the TFP design.

Could you give me any feedback of this question?

 

[eljose79]

Hello,

Thank you for your interest in TFP and your question about how it works. TFP, or Thin Film Polarizer, is a specialized optical component that is used to separate or filter out polarized light. It works by utilizing Brewster's angle, which is an angle at which light with a specific polarization (known as P-polarization) can pass through a surface with no reflection.

To better understand how TFP works, it is important to first understand the concept of polarization. Light is made up of electromagnetic waves that vibrate in different directions. When light is polarized, it means that the vibrations are limited to a specific direction. P-polarization refers to light with vibrations that are parallel to the plane of incidence (the plane containing the incident light ray and the surface it is hitting).

TFP is designed to only transmit P-polarized light, while reflecting S-polarized light. This is achieved by using a multi-layer dielectric coating on the TFP substrate. The coating is designed in a way that the P-polarized light will be transmitted through every surface of the coating and the substrate at Brewster's angle, while the S-polarized light will be highly reflected.

The design of the coating is crucial in achieving this separation of polarized light. It involves carefully selecting the refractive indices and thicknesses of the coating layers to ensure that the P-polarized light experiences constructive interference (allowing it to pass through) while the S-polarized light experiences destructive interference (resulting in high reflection).

In short, your understanding of TFP design is correct. It is a common approach to design TFP using a multi-layer dielectric coating to achieve high transmission of P-polarized light and high reflection of S-polarized light. I hope this helps to answer your question. Please let me know if you have any further inquiries.