Real-time Spectroscopy with Sub-GHz Resolution using Amplified Dispersive Fourier Transformation

TL;DR

This paper introduces a Raman amplified dispersive Fourier transformation technique that overcomes traditional sensitivity-resolution trade-offs, enabling real-time spectroscopy with sub-GHz resolution and record-breaking single-shot gas absorption measurements.

Contribution

The authors develop a Raman amplification method to achieve lossless dispersive Fourier transformation, significantly enhancing spectral resolution in real-time spectroscopy.

Findings

Achieved 950 MHz spectral resolution in real-time gas absorption spectroscopy

Demonstrated single-shot spectroscopy with record resolution

Overcame the power loss limitations of traditional dispersive Fourier transformation

Abstract

Dispersive Fourier transformation is a powerful technique in which spectral information is mapped into the time domain using chromatic dispersion. It replaces a spectrometer with an electronic digitizer, and enables real-time spectroscopy. The fundamental problem in this technique is the trade-off between the detection sensitivity and spectral resolution, a limitation set by the digitizer's bandwidth. This predicament is caused by the power loss associated with optical dispersion. We overcome this limitation using Raman amplified spectrum-to-time transformation. An extraordinary loss-less -11.76 ns/nm dispersive device is used to demonstrate single-shot gas absorption spectroscopy with 950 MHz resolution--a record in real-time spectroscopy.