Spatially patterned light amplification without inversion

Abstract

In this paper a method is proposed for achieving spatially dependent amplification without inversion (AWI) by exposing a quantum emitter to two weak probe beams carrying orbital angular momentum. The emitter has a double-V level scheme consisting of four energy levels in two interlinked V subsystems and possesses a closely spaced doublet of upper energy levels. Depending on the initial state, the system exhibits spatially patterned AWI, optical transparency, and light amplification with population inversion, which are contingent on the presence of quantum interference in spontaneous emission from the doublet. In a scenario when the emitter is positioned in proximity to a plasmonic nanostructure, the degree of AWI can be controlled by adjusting the metasurface-emitter separation. This allows precise control over light–matter interactions at the nanoscale and can lead to advanced quantum photonic devices.

Keywords

• Amplification without inversion
• Optical vortices
• Orbital angular momentum
• Plasmonic nanostructure
• Double-V quantum system
• Optical transparency