Enhanced Photoluminescence in High-Q Photonic Crystal Nanocavities with Er,O-Codoped GaAs

Abstract

Er,O-codoped GaAs is a promising candidate for application to light sources in fiber-optic communication, due to sharp luminescence from Er³⁺ ions at 1.54 µm and temperature insensitivity of their luminescence wavelength. In this report, we demonstrate coupling of luminescence from Er³⁺ ions in Er,O-codoped GaAs to the resonant mode of multi-step double heterostructure two-dimensional photonic crystal (PhC) nanocavities. The structure of the fabricated sample has an ultra-high designed cavity Q-factor of 1.7 × 10⁶. In micro-photoluminescence (µ-PL) measurements, ~25 and 1.7-fold enhancements of peak and integrated intensities from Er³⁺ ions are observed as the result from the coupling between Er luminescence and the cavity modes of the PhC nanocavities. Furthermore, incident pump power dependence of Er luminescence in the PhC nanocavity exhibits nonlinear behavior, whose possible models for the mechanism of the coupling are discussed. The obtained results would pave the way for understanding the interaction between cavity modes in PhC nanocavities and luminescence from rare-earth elements towards application in wavelength standards in fiber-optic communications or single photon emitters in quantum information technologies.