Abstract:
A light controlled light modulator is disclosed wherein a low intensity, circularly polarized driving light beam can be used to modulate or switch a linearly polarized main light beam. The main beam can be as much as three orders of magnitude more powerful than the driving beam, yet the response time is measured in picoseconds. The modulator itself comprises a coherent rotator and a polarizer, and modulation is accomplished by rotating the plane of polarization of the main beam under the control of the driving beam. The coherent rotator is a completely passive device and is a light cell containing an alkali metallic vapor such as rubidium or potassium.