Photoluminescence excitation and spectral hole burning spectroscopy of silicon vacancy centers in diamond

TL;DR

This study investigates silicon-vacancy centers in diamond using advanced spectroscopy techniques, revealing their spectral properties, linewidths, and coherence, which are crucial for quantum information and sensing applications.

Contribution

The paper provides high-resolution measurements of SiV center fine structure, demonstrates spectral hole burning to achieve near lifetime-limited linewidths, and shows coherent interactions in SiV ensembles.

Findings

Linewidths of about 10 GHz due to inhomogeneous broadening

Spectral hole burning reveals nearly lifetime-limited linewidth of 279 MHz

Evidence of coherent interaction via a $bc$-scheme

Abstract

Silicon-vacancy (SiV) centers in diamond are promising systems for quantum information applications due to their bright single photon emission and optically accessible spin states. Furthermore, SiV centers in low-strain diamond are insensitive to pertubations of the dielectric environment, i.e. they show very weak spectral diffusion. This property renders ensembles of SiV centers interesting for sensing applications. We here report on photoluminescence excitation (PLE) spectroscopy on an SiV ensemble in a low strain, CVD-grown high quality diamond layer, where we measure the fine structure with high resolution and obtain the linewidths and splittings of the SiV centers. We investigate the temperature dependence of the width and position of the fine structure peaks. Our measurements reveal linewidths of about 10 GHz as compared to a lifetime limited width on the order of 0.1 GHz. This difference arises from the inhomogeneous broadening of the transitions caused by residual strain. To overcome inhomogeneous broadening we use spectral hole burning spectroscopy which enables us to measure a nearly lifetime limited homogeneous linewidth of 279 MHz. Furthermore, we demonstrate evidence of coherent interaction in the system by driving a $\Lambda$-scheme. Additional measurements on single emitters created by ion implantation confirm the homogeneous linewidths seen in the spectral hole burning experiments and relate the ground state splitting to the decoherence rate.