Nanoscale optical parametric amplification through super-nonlinearity induction

Abstract

Optical parametric amplification (OPA) is a nonlinear process through which a low-power input wave is amplified by extracting energy from an interaction medium that is energized by a high-intensity pump wave. For a significant amplification of an input wave, a sufficiently long interaction medium is required, which is usually on the order of a few centimeters. Therefore, in the small scale, OPA is considered unfeasible, and this prevents it from being employed in micro and nanoscale devices. There have been recent studies that proposed microscale OPA through the use of micro-resonators. However, there is currently no study that has suggested high-gain nanoscale OPA, which could be quite useful for implementing nanoscale optical devices. This study aims to show that nanoscale OPA is feasible through the concurrent maximization of the pump wave induced electric energy density and the polarization density (nonlinear coupling strength) within the interaction medium, which enables a very high amount of energy to be transferred to the input wave that is sufficient to amplify the input wave with a gain factor that is comparable to those provided by centimeter scale nonlinear crystals. The computational results of our OPA model match with the experimental ones in the context of sum-harmonic generation, which is the wave-mixing process that gives rise to OPA, with an accuracy of 97.6%. The study aims to make room for further investigation of nanoscale OPA through adaptive optics and/or nonlinear programming algorithms for the enhancement of the process.

Plasmonic tuning of nano-antennas for super-gain light amplification

“…In the last decade there has been an interest on the use of plasmons for enhancing both the gain-factor and the gain-bandwidth of optical amplifiers [3][4][5][6]. Currently, most optical amplifiers are based on the technique of stimulated emission of radiation, which requires a gain medium, a source to energize the gain medium, and often a stable optical feedback mechanism [7,8]. These optical amplifiers are very commonly referred as lasers.…”

“…As a result, in many applications, the limited gain-bandwidth product constrains the performance and capabilities of the overall optical system as lasers are usually the most fundamental component in an integrated optical system. This limitation of stimulated emission based amplifiers can be avoided by using optical parametric amplifiers (OPAs) which can simultaneously provide a very high optical gain, and a large user-controlled bandwidth, thereby allowing for a huge gain-bandwidth product [8][9][10][11]. For this reason, at first sight OPAs may seem to be the ultimate solution to enhance the amplification capabilities of integrated optical devices.…”

“…However, OPAs require very high pump intensities to provide a gain factor that can surpass that of lasers. Furthermore, this requires large and bulky energy sources and hinders the feasibility of employing OPAs in integrated photonic devices [7,8].…”

“…Different designs and scenarios have been proposed to come up with the ideal optical amplifier configuration, especially for the case of OPAs [7][8][9][10][11]. A prominent technique is the creation of artificial materials with extraordinary electrical non-linearity to provide OPA at a lower pump wave intensity.…”

“…A prominent technique is the creation of artificial materials with extraordinary electrical non-linearity to provide OPA at a lower pump wave intensity. Other techniques involve altering the structure of an OPA system for super-nonlinearity, or to excite the structure in a special manner such that an extraordinary non-linearity is induced [8]. This indeed relaxes the high-intensity requirement for a given pump wave during OPA, but it still does not make OPAs favorable in small-scale optical devices due to the requirement of a sufficient interaction medium length, which should be on the order of centimeters [10].…”