Accurate alignment of a photonic crystal nanocavity with an embedded quantum dot based on optical microscopic photoluminescence imaging

Abstract

We have developed a technique to align a two-dimensional photonic-crystal nanocavity (PCNC) with an indium arsenide/gallium arsenide self-assembled quantum dot (QD), using microscopic photoluminescence (μ-PL) spectroscopy to image a wafer with a low-density of QDs and pre-formed positioning marks. Individual QD emission wavelengths were evaluated from μ-PL spectra, and positions relative to the marks were determined. The wavelength detuning between the QD-emission peak and the PCNC resonant frequency was < 4 nm, and the alignment standard deviation was < 50 nm. The emission peaks of a single QD and a PCNC aligned by this technique showed anti-crossing, implying high accuracy.