Degenerate phase-matching for multi-wavelength nonlinear mixing in aperiodic lattice lasers

TL;DR

This paper investigates how aperiodic lattice designs in THz lasers can enhance multi-wavelength nonlinear frequency conversion through degenerate phase-matching, potentially improving wavelength multiplexing in THz communication systems.

Contribution

It introduces a nonlinear transfer matrix model to analyze degenerate phase-matching in aperiodic lattice lasers, revealing resonant enhancement and conditions for multi-wavelength operation.

Findings

Resonant enhancement of nonlinear conversion efficiency at high photon lifetime frequencies

Degenerate phase-matching linked to absence of dispersion and low thresholds

Multi-wavelength defect modes with degenerate pump frequencies

Abstract

Holographically-designed aperiodic lattices have proven to be an exciting engineering technique for achieving electrically switchable single- or multi-frequency emissions in terahertz (THz) semiconductor lasers. Here, we employ the nonlinear transfer matrix modeling method to investigate multi-wavelength nonlinear (sum- or difference-) frequency generation within an integrated THz (idler) laser cavity that also supports optical (pump and signal) waves. The laser cavity includes an aperiodic lattice, which engineers the idler photon lifetimes and effective refractive indices. The key findings are: (i) the nonlinear conversion efficiency reveals resonant enhancement at those idler frequencies where the photon lifetime is high; (ii) the resonant phase-matching process between the pump and idler waves has a one-to-one link with absence of any other dispersion, the lowest threshold, multi-wavelength defect modes of the aperiodic lattice laser have degenerate phase-matched pump frequencies. This set of results will potentially have a significant impact on the wavelength multiplexing in electronically switchable THz-over-fiber communication systems [1].