Spectral broadening of a single Er$^{3+}$ ion in a Si nano-transistor

Abstract

Single rare-earth ions in solids show great potential for quantum applications, including single photon emission, quantum computing, and high-precision sensing. However, homogeneous linewidths observed for single rare-earth ions are orders of magnitude larger than the sub-kilohertz linewidths observed for ensembles in bulk crystals. The spectral broadening creates a significant challenge for achieving entanglement generation and qubit operation with single rare-earth ions, so it is critical to investigate the broadening mechanisms. We report a spectral broadening study on a single Er 3+ ion in a Si nano-transistor. The Er-induced photoionisation rate is found to be an appropriate quantity to represent the optical transition probability for spectroscopic studies, and the single ion spectra display a Lorentzian lineshape at all optical powers in use. Spectral broadening is observed at relatively high optical powers and is caused by spectral diffusion on a fast time scale.

The Zeeman and hyperfine interactions of a single $^{167}Er^{3+}$ ion in Si

“…Multi-peak fitting with Lorentzian functions was used to determine the peak positions. The full width at half maximum (FWHM) of the isolated peaks was approximately 32 MHz [32]. Since the spectra were measure with a finite step size of 20 MHz, the apparent peak heights in Figs.…”