Question on beamsplitter when light is backward-incident

[swengzju]

Hi all,

I'm new to this forum and not sure if this is the right place to post this question.

I know that beamsplitters normally have dielectric coating on one side and AR coating on the other side. I'm looking at this plate beamsplitter specifically: https://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=4808

I want to know what would happen if light is incident inversely, eg, it hits AR coating first then the dielectric coating. Will I get part of the light going downwards and the rest going through the beamsplitter?

Basically I'm looking for a beamsplitter that only allows on-way transmission.

Any help is greatly appreciated!

 

[mfb]

One-way transmission violates the second law of thermodynamics, it would allow to reduce entropy. I don't know how this beamsplitter would behave, but there is no one-way-transmission (neglecting exotic non-linear effects that are not relevant here).

 

[Daz]

It will work the same both ways around. There are no one-way mirrors.

 

[Andy Resnick]

Using a dielectric beamsplitter 'backwards' decreases the efficiency, as does using it at an off-nominal angle of incidence.

https://www.chroma.com/knowledge-resources/fluorescence-filters/optical-properties-specifications