On exciton squeezing in semiconductors

Abstract

We consider an optidly excited semiconductor as a coherent system of interacting excitons and phmns. Within the boson formalism and secular approximation the analytical expressions for the exciton quadrature variances are rigorously derived. The analysis of these variances over the relevant parameter space shows that initially coherent excitons can evolve into squeezed states in a finite-size senkonductor, which must possess both linear and non-linear interactions.

Density-Dependent Phonoriton States in Highly Excited Semiconductors

“…Recently the quantum optical properties of the quasiparticles in condensed matters have been investigated intensively [1][2][3][4][5][6][7][8][9][10]. In particular, the nonclassical properties of exciton-polariton were considered in [1][2][3], phonon-polariton in [4], and squeezed states of excitons were considered in [5][6][7]. Of particular interest are also the optical nonlinearities emerged from high external excitation which affect almost all the optical properties of semiconductors.…”

“…The equations of motion for the Green's functions (4,5) can be derived in standard way. Then using the RPA-type factorization which is reasonable for high densities, we obtain the closed system of equations, the solutions of which give us the spectrum of the exciton-polariton, as follows…”

“…Recently the quantum optical properties of the quasiparticles in condensed matters have been investigated intensively [1][2][3][4][5][6][7][8][9][10]. In particular, the nonclassical properties of exciton-polariton were considered in [1][2][3], phonon-polariton in [4], and squeezed states of excitons were considered in [5][6][7].…”

“…At high excitation a great number of excitons can be produced and there arise some kinds of anharmonicities such as nonlinear exciton-exciton interaction and the anharmonic exciton-photon interaction due to phase-space filling of excitons. An attempt to consider the effect of these anharmonicities on squeezed states of excitons was first made in [5][6][7]. However, in [5,6] to solve the problem the authors had to resort to rough approximation neglecting many terms in Hamiltonian which actually should be retained.…”

“…An attempt to consider the effect of these anharmonicities on squeezed states of excitons was first made in [5][6][7]. However, in [5,6] to solve the problem the authors had to resort to rough approximation neglecting many terms in Hamiltonian which actually should be retained. It is well known that for the high density systems where the fluctuations of the occupation number can be neglected, the Random Phase Approximation (RPA) [11] is the most suitable, and one can safely apply it to study nonlinear optical properties of the system.…”