Sub-megahertz homogeneous linewidth for Er in Si via in situ single photon detection

TL;DR

This study demonstrates ultra-narrow homogeneous linewidths in Er-doped silicon using in situ single photon detection, revealing promising properties for quantum communication.

Contribution

Introduces a novel, fabrication-free method for high-efficiency detection of Er resonances in silicon, discovering 63 new resonances and significantly narrowing linewidths.

Findings

Homogeneous linewidths as narrow as 0.75 MHz observed.

Detected 70 excitation frequencies, 63 of which are novel.

Optical lifetimes range from 0.5 ms to 1.5 ms.

Abstract

We studied the optical properties of a resonantly excited trivalent Er ensemble in Si accessed via in situ single photon detection. A novel approach which avoids nanofabrication on the sample is introduced, resulting in a highly efficient detection of 70 excitation frequencies, of which 63 resonances have not been observed in literature. The center frequencies and optical lifetimes of all resonances have been extracted, showing that 5% of the resonances are within 1 GHz of our electrically detected resonances and that the optical lifetimes range from 0.5 ms up to 1.5 ms. We observed inhomogeneous broadening of less than 400 MHz and an upper bound on the homogeneous linewidth of 1.4 MHz and 0.75 MHz for two separate resonances, which is a reduction of more than an order of magnitude observed to date. These narrow optical transition properties show that Er in Si is an excellent candidate for future quantum information and communication applications.