# How to make a rotating linearly polarized (not circular polarization) beam from a single beam?

One way to make a linearly polarized beam rotating at frequency $\Delta f\approx10\mbox{MHz}$ is by combining two circularly polarized beams, one left-handed and one right-handed, and where one beam is at a frequency $f$ and the other at $f\pm\Delta f$. Is there another way to do this using only a single beam passed through some active optical device (eg electro-optic-modulator)? I'm interested in the mid-infrared (10.6um).

• Just put a polarizing filter there and rotate it with an electric motor, if you don't need very high rotation frequency that would do what you want. Oct 14, 2014 at 16:59
• Unfortunately I would need frequency of about 10MHz. I'll edit the question. Oct 14, 2014 at 18:10