A flexible eye-safe lidar instrument for elastic-backscatter and DIAL

Iain Robinson, Jim Jack, Cameron Rae, John Moncrieff

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Developments in lidar have been driven largely by improvements in two key technologies: lasers and detectors. We describe here a lidar instrument for atmospheric remote sensing using the elastic-backscatter and differential-absorption lidar (DIAL) techniques. The instrument features an all-solid-state laser source combined with a flexible approach to detection providing portability, eye-safe operation and high sensitivity. The system is built around a custom-designed Newtonian telescope with a 0.38 m diameter primary mirror. Laser sources and detectors attach directly to the side of the telescope allowing for flexible customization with a range of equipment. The laser source is based on an optical parametric oscillator (OPO). The OPO is pumped by a neodymiumbased diode-laser pumped solid-state laser and angle-tuned by rotating the nonlinear conversion crystal. This provides a wide range of available wavelengths suitable for lidar within the 1.55 µm to 3.10 µm spectral region, where there exists a relatively high exposure limit for eye safety. The OPO delivers 1 mJ output pulse energy which is expanded and then transmitted coaxially from the telescope. Our goal is to make vertically-resolved measurements of greenhouse gas concentrations using DIAL. The source can rapidly be tuned between the on-line and off-line wavelengths to make a DIAL measurement. The use of the 1.6 µm wavelength region allows for several detection schemes. Whilst photodiode detectors are a very low-cost solution their limited sensitivity restricts the maximum range over which a signal can be detected. We therefore have designed the instrument to support alternative detection schemes including avalanche photodiodes (APDs).
Original languageEnglish
Title of host publicationProceedings of SPIE
PublisherSPIE
DOIs
Publication statusPublished - 1 Nov 2012
EventSPIE Remote Sensing 2012 - Edinburgh, United Kingdom
Duration: 24 Sep 201227 Sep 2012

Conference

ConferenceSPIE Remote Sensing 2012
CountryUnited Kingdom
CityEdinburgh
Period24/09/1227/09/12

Keywords

  • Absorption
  • Atmospheric sensing
  • Avalanche photodetectors
  • Avalanche photodiodes
  • Backscatter
  • Crystals
  • Equipment and services
  • Eye
  • LIDAR
  • Laser eye protection

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