Modulation of laser radiation in liquid thin-film waveguides

An investigation was made of liquid waveguide modulators utilizing liquid crystals and nitrobenzene. A 50% depth of amplitude modulation was achieved for He-Ne laser radiation (0.63 μ) by applying a modulation voltage of about 100 V at a frequency of 50 kHz to liquid-crystal thin-film waveguides based on the orientation modulation of absorption. Polarization modulation of the radiation emitted by an injection laser was achieved in a nitrobenzene thin-film waveguide; in this case the depth of modulation was 90% when the modulation voltage was 60 V and its frequency was of the order of 1–2 MHz.