Coherent amplification and inversion less lasing of surface plasmon polaritons in a negative index metamaterial with a resonant atomic medium

Saeid Asgarnezhad-Zorgabad

doi:10.1038/s41598-021-82909-7

Abstract

Surface plasmon polaritons (SPPs) lasing requires population inversion, it is inefficient and possesses poor spectral properties. We develop an inversion-less concept for a quantum plasmonic waveguide that exploits unidirectional superradiant SPP (SSPP) emission of radiation to produce intense coherent surface plasmon beams. Our scheme includes a resonantly driven cold atomic medium in a lossless dielectric situated above an ultra-low loss negative index metamaterial (NIMM) layer. We propose generating unidirectional superradiant radiation of the plasmonic field within an atomic medium and a NIMM layer interface and achieve amplified SPPs by introducing phase-match between the superradiant SPP wave and coupled laser fields. We also establish a parametric resonance between the weak modulated plasmonic field and the collective oscillations of the atomic ensemble, thereby suppressing decoherence of the stably amplified directional polaritonic mode. Our method incorporates the quantum gain of the atomic medium to obtain sufficient conditions for coherent amplification of superradiant SPP waves, and we explore this method to quantum dynamics of the atomic medium being coupled with the weak polaritonic waves. Our waveguide configuration acts as a surface plasmon laser and quantum plasmonic transistor and opens prospects for designing controllable nano-scale lasers for quantum and nano-photonic applications.

Highlights

Inversion-less lasing and coherent amplification of SPP waves need three concepts that are intensively investigate in previous studies: (i) superradiant emission of radiation, (ii) parametric resonance, and (iii) weak field amplification and stability analysis
We present the main results of this paper in four sections: First, we give a qualitative description of directional SSPP propagation and directional SPP lasing operation in “Brief description of SSPP launching and SPP lasing operation”
“Surface plasmon polariton amplification” we present the details of weak SPP field amplification in the presence of this directional plasmonic superradiant radiation

Summary

Introduction

Inversion-less lasing and coherent amplification of SPP waves need three concepts that are intensively investigate in previous studies: (i) superradiant emission of radiation, (ii) parametric resonance, and (iii) weak field amplification and stability analysis. We begin this section by briefly reviewing the superradiant emission of radiation in “Superradiant emission of radiation”. We introduce the parametric resonance and discuss the possibility of providing gain for a weak driving field “Parametric resonance”. We review the salient aspect of the weak field amplification using the Mathieu equation. This concept is discussed in “Weak field amplification and dynamical stability”. We elucidate the pertinent concept of the superradiant emission of radiation[36,37,38]. For a N two-level atoms with ground state |b and excited state |a that are situated within a cell of radius R much smaller than the radiation wavelength , a uniform absorption of photon by a single quantum emitter prepares the atomic ensemble to the so called Dicke-state

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