Beam deflection and amplitude modulation of 10.6‐μm guided waves by free‐carrier injection in GaAs–AlGaAs heterostructures

Beam deflection and amplitude modulation of 10.6‐μm guided waves by photoinjected free carriers are demonstrated in thin‐film GaAs–AlGaAs heterostructure waveguides. At high injection levels (N ≳ 5 × 1017 cm−3), amplitude modulation (up to 100%) of the 10.6‐μm guided wave dominates, but at lower injection levels beam deflection is dominant. External deflection angles of the order of 1° are obtained with nanosecond response times.