Non-blinking single-photon emitters in silica

TL;DR

This paper demonstrates that intrinsic defect centers in silica, such as borosilicate glass and quartz, can serve as stable, non-blinking single-photon emitters with specific spectral features, potentially misidentified as quantum dots.

Contribution

It reveals that intrinsic defects in common glass materials can act as stable single-photon sources, challenging the assumption that such emitters are always external nanocrystals.

Findings

Defect centers in silica fluoresce under 532 nm excitation.

These defect emitters do not blink and have nanosecond lifetimes.

Spectral features suggest coupling to silica vibrations.

Abstract

Samples for single-emitter spectroscopy are usually prepared by spin-coating a dilute solution of emitters on a microscope cover slip of silicate based glass (such as quartz). Here, we show that both borosilicate glass and quartz contain intrinsic defect colour centres that fluoresce when excited at 532 nm. In a microscope image the defect emission is indistinguishable from spin-coated emitters. The emission spectrum is characterised by multiple peaks, most likely due to coupling to a silica vibration with an energy of 160-180 meV. The defects are single-photon emitters, do not blink, and have photoluminescence lifetimes of a few nanoseconds. Photoluminescence from such defects may previously have been misinterpreted as originating from single nanocrystal quantum dots.