Local Density-of-States Mapping in Photonic Crystal Resonators by Deterministically Positioned Germanium Quantum Dots

TL;DR

This study demonstrates a scalable method for mapping the local density of states in photonic crystal resonators using precisely positioned germanium quantum dots, with results aligning well with simulations.

Contribution

We developed a scalable, deterministic positioning technique for Ge quantum dots in photonic crystal cavities, enabling detailed local density-of-states mapping.

Findings

High alignment precision (<20 nm) of quantum dots achieved.

Successful correlation between experimental coupling and simulations.

Scalable fabrication process compatible with standard silicon technology.

Abstract

We report on mapping of the local density of states in L3 photonic crystal resonators (PCR) via deterministically positioned single Ge quantum dots (QDs). Perfect site-control of Ge QDs on pre-patterned silicon-on-insulator substrates was exploited to fabricate in one processing run almost 300 L3 PCRs containing single QDs in systematically varying positions in the cavities. The alignment precision of the QD emitters was better than 20 nm. This type of parallel processing is essentially based on standard Si device technologies and is therefore scalable to any number and configuration of PCR structures. As a first demonstrator, we probed the coupling efficiency of a single Ge QD to the L3 cavity modes as a function of their spatial overlap. The results are in very good agreement with finite-difference time-domain simulations.