Multi-heterodyne differential absorption lidar based on dual-comb spectroscopy for simultaneous greenhouse gas and wind speed measurements

TL;DR

This paper presents a dual-comb spectroscopy-based multi-heterodyne differential absorption lidar system capable of simultaneously measuring atmospheric greenhouse gases and wind speed over a 1.4 km path, demonstrating its potential for advanced environmental monitoring.

Contribution

It introduces a novel lidar architecture that combines dual-comb spectroscopy with multi-frequency Doppler wind measurements for concurrent greenhouse gas and wind speed sensing.

Findings

Successful atmospheric CO2 measurement over 1.4 km

Simultaneous wind speed and gas concentration measurements achieved

High power per comb tooth enhances measurement capabilities

Abstract

In a recent study [1], we demonstrated a multi-heterodyne differential absorption lidar (DIAL) for greenhouse gas monitoring utilizing solid targets. The multi-frequency absorption measurement was achieved using electro-optic dual-comb spectroscopy (DCS) with a minimal number of comb teeth to maximize the optical power per tooth. In this work, we examine the lidar's working principle and architecture. Additionally, we present measurements of atmospheric CO2 at 1572 nm over a 1.4 km optical path conducted in summer 2023. Furthermore, we show that, due to the high power per comb tooth, multi-frequency Doppler wind speed measurements can be performed using the DCS signal from aerosol backscattering. This enables simultaneous radial wind speed and path-average gas concentration measurements, offering promising prospects for novel concepts of tunable multi-frequency lidar systems capable of simultaneously monitoring wind speed and gas concentrations. [1] W. Pati\~no Rosas and N. C\'ezard, "Greenhouse gas monitoring using an IPDA lidar based on a dual-comb spectrometer," Opt. Express 32, 13614-13627 (2024).