General Properties of the Linear Optical Response

Philippe Tamarat, Fedor Jelezko, Ch. Brunel +3 more

Haruki Watanabe, Yankang Liu, Masaki Oshikawa

Abstract The optical conductivity is the basic defining property of materials characterizing the current response toward time-dependent electric fields. In this work, following the approach of Kubo’s response theory, we study the general properties of the nonlinear optical conductivities of quantum many-body systems both in equilibrium and non-equilibrium. We obtain an expression of the second- and the third-order optical conductivity in terms of correlation functions and present a perturbative proof of the generalized Kohn formula proposed recently. We also discuss a generalization of the f-sum rule to a non-equilibrium setting by focusing on the instantaneous response.

Mohammad H. Asghari, José Azaña

We introduce and numerically demonstrate a simple and general concept for direct reconstruction of the temporal phase profile of an optical signal from temporal intensity measurements at the input and output of an arbitrary linear optical filter. The concept is based on exploiting the linearity and causality properties of any physical filter. Very few restrictions need to be imposed on the optical filter response to ensure an unambiguous phase reconstruction. The filter can be specifically designed to minimize the noise influence on the measurement process.

M. Dagenais, Wayne F. Sharfin

A general discussion of the linear-optical properties of free and bound excitons in direct-gap semiconductors at low temperature is presented. This discussion then specializes to CdS. The nonlinear-optical response of CdS is introduced by first discussing the saturation behavior of bound excitons. A new type of cavityless optical bistability based on induced absorption near the free and bound excitons is described. Finally, fast all-optical switching (<1 nsec) at very low switching energies (<8 pJ) is demonstrated, using the giant nonlinearity associated with bound excitons.