Ultrafast measurement of a single-photon wave packet using an optical Kerr gate

Abstract

Ultrafast quantum optics with time-frequency entangled photons is at the forefront of progress towards future quantum technologies. However, to unravel the time domain structure of entangled photons and exploit fully their rich dimensionality, a single-photon detector with sub-picosecond temporal resolution is required. Here, we present ultrafast single-photon detection using an optical Kerr gate composed of a photonic crystal fiber (PCF) placed inside a Sagnac interferometer. A near-rectangle temporal waveform of a heralded single-photon generated via spontaneous parametric down-conversion is measured with temporal resolution as high as 224 ± 9 fs. The large nonlinearity and long effective interaction length of the PCF enables maximum detection efficiency to be achieved with only 30.5 mW gating pulse average power, demonstrating an order-of-magnitude improvement compared to optical gating with sum-frequency generation. Also, we discuss the trade-off relationship between detection efficiency and temporal resolution.

Ultrafast time-resolved single-photon detection using two-color comb based asynchronous optical sampling for quantum applications

“…In the past, there have been investigations on fast gating methods to resolve single photons temporally. Notably, optical gating methods such as sum-frequency generation 2 (SFG) and the optical Kerr gating 3 technique have demonstrated sub-picosecond down to a few hundred femtoseconds of time resolution. However, these approaches are constrained by limited detection sensitivity as they rely on mechanical translational stages, similar to traditional pump-probe ultrafast time domain measurements.…”

Single-photon level ultrafast time-resolved measurement using two-color dual-comb-based asynchronous linear optical sampling

“…The highest temporal resolution to date has been achieved via the optical Kerr gating technique, which enabled a timing resolution of 224 ± 9 fs. 8) However, these methods rely on mechanical translational stages to adjust the time delay between pump and probe pulses similar to traditional pump-probe ultrafast time-domain measurements. However, the speed of the motorized stages does not allow for rapid scan rates and poses a risk to introduce measurement uncertainties due to mechanical vibrations or backlash, beampointing instabilities, and possible wavefront deformations.…”