Abstract

Quantum interference may occur when coherent superposition of real close-spaced states are involved in a process. Alternatively, interfering frequency-degenerate intraatomic oscillations may originate from different correlated quantum pathways, contributing in one and the same process. Three-level schematic is a simplest model to study such interference effects. One of the applications is lasing without inversion (LWI). The requirements, which must be met in three-level optical schematics in order to optimize LWI have been studied and formulated as early as in 1969 [1]. The "double-lambda” schemes are mostly discussed recently towards inversionless amplification. Both continuous - wave (CW) Raman gain and four-wave mixing (FWM) at the transitions between is and 2p levels of Nc and in dimer Na₂ transitions were investigated in the experiments [2]. New questions, such as effects of Doppler broadening and auxiliary strong fields on constructive and destructive quantum interference have been raised.

© 1996 IEEE