Room-temperature 1.54 $\mu$m photoluminescence of Er:O$_x$ centers at extremely low concentration in silicon

摘要

The demand for single photon sources at $\lambda~=~1.54~\mu$m, which followsfrom the consistent development of quantum networks based on commercial opticalfibers, makes Er:O$_x$ centers in Si still a viable resource thanks to theoptical transition of $Er^{3+}~:~^4I_{13/2}~\rightarrow~^4I_{15/2}$. Yet, todate, the implementation of such system remains hindered by its extremely lowemission rate. In this Letter, we explore the room-temperaturephotoluminescence (PL) at the telecomm wavelength of very low implantationdoses of $Er:O_x$ in $Si$. The emitted photons, excited by a $\lambda~=~792~nm$laser in both large areas and confined dots of diameter down to $5~\mu$m, arecollected by an inverted confocal microscope. The lower-bound number ofdetectable emission centers within our diffraction-limited illumination spot isestimated to be down to about 10$^4$, corresponding to an emission rate perindividual ion of about $4~\times~10^{3}$ photons/s.