Abstract

Nonlinear optical phenomena in dense resonant media are of growing interest. These media are expected to possess an intrinsic (resonatorless) optical bistability. A lot of research¹ was devoted to the possible optical bistable response from thin layers containing "two-level atoms" (TLAs), i.e., atoms or molecules with a resonant dipole transition. A thin layer containing a "gas" of TLAs was predicted² to possess a peculiar transient response to a light pulse. Later a regime of optical bistability was discussed for the response of such a layer to a stationary optical excitation. An actual problem is the description of layers with a high density of TLAs when the "gas" approximation breaks down and the interaction of TLAs becomes important. These near-dipole-dipole interaction effects in a dense system are usually treated by means of the Lorentz-Lorenz correction to the local electric field (see Refs. 3–5 and refs, therein). In the framework of this approach the corrections to the local field modify the usual optical Bloch equation. On the basis of the modified Bloch equations, a variety of phenomena have been predicted for both the transient and the steady-state behavior of the system of the TLAs.

© 1994 IEEE