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

Masahiro Yabuno, Takahiro Takumi, Fumihiro China, Shigehito Miki, Hirotaka Terai, Peter J. Mosley, Rui-Bo Jin, Ryosuke Shimizu

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)


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.
Original languageEnglish
Pages (from-to)4999-5007
Number of pages9
JournalOptics Express
Issue number4
Publication statusPublished - 14 Feb 2022

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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