Abstract

In a dc biased or built-in asymmetric quantum well (QW) structure, a net charge polarization would be induced by virtual excitations caused by an off-resonant pump light with a photon energy h_ω far below the fundamental excitonic gap of the QW. The induced virtual charge polarizations may partially screen the original field E₀, resulting in a decrease of the internal field,^1,2 One of the most striking features of this modulation scheme, named virtual charge- Induced optical nonlinearity (VCON),¹ is the possibility of generation of ultrafast voltage pulses in a diode exhibiting multi-QW structure.² The possibility of ultrafast electrostatic control of quantum interference currents through the voltage pulse generation has been discussed.³ We propose and discuss a new modulation scheme of the quantum interference currents based on more direct interactions, i.e., exchange interactions between coherent election waves and photoexcited virtual pairs.

© 1990 Optical Society of America