Techniques for laser remote sensing of the environment

Abstract

The principles and the basic performance of laser remote sensors are classified and compared. The present state of the art of laser remote sensing techniques and applications for monitoring environmental parameters are reviewed. Future possibilities and requirements of research and development of these techniques are discussed.

Low-power noncontact photoacoustic microscope for bioimaging applications

“…[2][3][4][5][6][7][8][9][10][11][12] The low-power PA technique has been predominantly utilized in the field of spectroscopy, [11][12][13][14][15][16][17][18] with substantial applications in trace gas detection. 5,[19][20][21][22][23] It exhibited significantly higher sensitivity than most other techniques, [24][25][26][27] with concentration sensitivity in the parts per billion. [3][4][5]25,27 PA spectroscopy is a powerful analytical tool for examining the optical absorption properties of solids as it directly measures the energy absorbed by the material on exposure to light.…”

“…5,[19][20][21][22][23] It exhibited significantly higher sensitivity than most other techniques, [24][25][26][27] with concentration sensitivity in the parts per billion. [3][4][5]25,27 PA spectroscopy is a powerful analytical tool for examining the optical absorption properties of solids as it directly measures the energy absorbed by the material on exposure to light. 28 Conventional optical absorption/transmission spectroscopy requires a sample with a specialized surface as the scattering would significantly affect the accuracy of the measurement of optical absorption coefficient.…”

DIAL, a system for atmospheric methane measurement over Guwahati: development and results

“…The multi-wavelength DIAL system is, however, capable of high-precision measurement compared to a dual-DIAL and can also simultaneously monitor several target elements (Fukuchi et al 1998). Thus, depending on applications, DIAL uses different probing frequencies (Baumgartner and Byer 1978, Measures 1984, Kobayashi 1987. The initial DIAL measurements were confined to making humidity profiles and then NO 2 detection.…”

Análise de dados de sistema LIDAR de retroespalhamento correlacionada com dados meteorológicos

“…Fonte: Rosário (2006). 53 Figura 3.7 Representação esquemática do conjunto fotodetector do MFRSR durante o seu funcionamento (Sayão, 2008 O sensoriamento remoto da atmosfera com a utilização do laser tornou-se um poderoso instrumento no seu estudo e, dada a sua semelhança de operação e princípios físicos com as técnicas de radar, recebeu o nome de LIDAR, acrônimo para Light Detection and Ranging (Kobayashi, 1987, Measures, 1984 (Maiman,1960). No mesmo ano, foi demonstrado o funcionamento do laser de He-Ne, que é o laser na região do visível mais conhecido (Jenkis, 1981).…”

“…Na aplicação de monitoração de poluentes na atmosfera, os sistemas LIDAR podem fornecer, com uma fonte de laser de comprimento de onda de largura de banda estreita, informação da presença e distribuição de partículas de uns poucos nanômetros a cerca de 100 µm de diâmetro e, se o LIDAR for operado com dois sinais distintos em comprimento de onda, pode-se obter informação da concentração específica do conteúdo de gases na atmosfera, atingindo-se um nível de sensibilidade de até 0,1 ppb, no caso das concentrações moleculares (Kobayashi, 1987).…”