Compact transient-grating self-referenced spectral interferometry for sub-nanojoule femtosecond pulses characterization

TL;DR

This paper presents a miniaturized, highly sensitive self-referenced spectral interferometry method capable of characterizing femtosecond pulses with energies as low as 0.5 nJ, expanding its application scope.

Contribution

It introduces a compact, transient-grating based SRSI technique that effectively measures ultra-weak femtosecond pulses, previously limited to microjoule energies.

Findings

Successfully characterized 3 nJ pulses at 1 kHz

Successfully characterized <0.5 nJ pulses at 84 MHz

Device size smaller than a palm

Abstract

The self-referenced spectral interferometry (SRSI) technique, which is usually used for microjoule-level femtosecond pulses characterization, is improved to characterize weak femtosecond pulses with nanojoule based on the transient-grating effect. Both femtosecond pulses from an amplifier with 3 nJ per pulse at 1 kHz repetition rates and femtosecond pulses from an oscillator with less than 0.5 nJ per pulse at 84 MHz repetition rates are successfully characterized. Furthermore, through a special design, the optical setup of the device is even smaller than a palm which will makes it simple and convenient during the application. These improvements extend the application of SRSI technique to the characterization of femtosecond pulses in a broad range. Not only pulses from an amplifier but also pulses from an oscillator or weak pulses used in ultrafast spectroscopy can be monitored with this SRSI method right now.