| Abstract: | We propose a new method for the formation of light-induced transient gratings in microwave-biased semiconductor crystals that exhibit a negative differential resistivity. Nonuniform heating of the electron gas in alternating electric fields induces spatially periodic modulation of the refractive index with spacing that is tunable by the external field frequency. Numerical simulations performed on a bulk GaAs sample prove that transient parametric gratings of both free-carrier and electro-optic origin can be triggered by a spatially modulated light pattern or by uniform photoexcitation. |
