Oral: Programmable formation of telecom band quantum emitters in silicon*

Silicon-based quantum emitters are candidates for large-scale qubit integration due to their single-photon emission properties and potential for spin-photon interfaces with long spin coherence times.  Here, we demonstrate local writing and erasing of selected light-emitting defects using fs laser pulses in combination with hydrogen-based defect activation and passivation. By selecting forming gas (N₂/H₂) during thermal annealing of carbon-implanted silicon, we form C_i centers while passivating the more common G-centers.  The C_i center is a telecom S-band emitter with very promising spin properties that consists of a single interstitial carbon atom in the silicon lattice.  Density functional theory calculations show that the C_i center brightness is enhanced by several orders of magnitude in the presence of hydrogen.   Fs-laser pulses locally affect the passivation or activation of quantum emitters with hydrogen and enable programmable quantum emitter formation in a qubit-by-design paradigm.