Indistinguishable Single Photons from Nanowire Quantum Dots in the Telecom O-Band

Abstract

On-demand single-photon sources operating at telecom wavelengths are crucial for quantum communication and photonic quantum technologies. In this work, we demonstrate high-purity, indistinguishable single-photon generation in the telecom O-band from an InAsP/InP nanowire quantum dot. We measured a single-photon purity of $g^2(0)=0.006(3)$ under aboveband excitation. Furthermore, we characterize two-photon interference via Hong-Ou-Mandel measurements and achieve a photon indistinguishability of $94.6\,\%$ with a temporal postselection of 100 ps time window and $5.58\,\%$ without temporal postselection. We measure a first-lens source efficiency of $\sim28\,\%$. These results highlight the potential of nanowire quantum dots as a promising source of telecom single photons for photonic quantum applications, offering deterministic positioning, efficient photon extraction, and scalable production.

Figures (4)

• Figure 1: (a) The quantum light source consists of an InP core, an InAsP quantum dot (QD), and an InP shell. The figure shows an SEM image of the nanowire QD on the growth chip. Experimental setup: (b) Confocal microscopy setup, (c) nitrogen-cooled InGaAs spectrometer, (d) HOM setup, and (e) superconducting nanowire single-photon detectors (SNSPDs)
• Figure 2: Spectral characterization of the quantum dot emission (a) Emission spectra of the nanowire quantum dot under above band excitation at 793 nm. (b) Radiative lifetime of the charged exciton fitted to a single exponential (red line). (c) Autocorrelation function of the charged exciton under above band pulsed excitation at 793 nm wavelength.
• Figure 3: Two photon interference under pulsed excitation at saturation power. (a) and (b) Co-polarized. (c) and (d) Cross-polarized. (b) and (d) are a zoom into the zero delay peak.
• Figure 4: Extracted visibility and fraction of coincidences for different integration time windows.