Spectral broadening and shaping of nanosecond pulses: towards shaping of single photons from quantum emitters

TL;DR

This paper demonstrates spectral broadening and shaping of nanosecond pulses using nonlinear mixing in PPLN, enabling potential spectral and temporal control of single photons for quantum applications.

Contribution

It introduces a method for spectral shaping of nanosecond pulses compatible with single photon states, including experimental demonstration and numerical feasibility analysis.

Findings

Spectral broadening up to 10 times shorter than original pulses.

Feasibility of spectral phase correction for temporal compression.

Compatible with quantum single photon states.

Abstract

We experimentally demonstrate spectral broadening and shaping of exponentially-decaying nanosecond pulses via nonlinear mixing with a phase-modulated pump in a periodically-poled lithium niobate (PPLN) waveguide. A strong, 1550~nm pulse is imprinted with a temporal phase and used to upconvert a weak 980 nm pulse to 600 nm while simultaneously broadening the spectrum to that of a Lorentzian pulse up to 10 times shorter. While the current experimental demonstration is for spectral shaping, we also provide a numerical study showing the feasibility of subsequent spectral phase correction to achieve temporal compression and re-shaping of a 1~ns mono-exponentially decaying pulse to a 250 ps Lorentzian, which would constitute a complete spectro-temporal waveform shaping protocol. This method, which uses quantum frequency conversion in PPLN with >100:1 signal-to-noise ratio, is compatible with single photon states of light.