Trace Gas Measurement Using Ir Laser Diodes
نویسندگان
چکیده
The properties of semiconductor laser diodes for trace gas measurements are reviewed. First, the modulation characteristics of these lasers are discussed. Then, two sensitive spectroscopic methods using a frequency-modulated near-IR laser are presented and their performance compared. In the λ = 2 μm range, second-harmonic optical detection has shown a 20 times better detection limit than photoacoustic detection. The extension of these methods to longer wavelengths is finally discussed.
منابع مشابه
Diode laser absorption sensors for gas-dynamic and combustion flows.
Recent advances in room-temperature, near-IR and visible diode laser sources for tele-communication, high-speed computer networks, and optical data storage applications are enabling a new generation of gas-dynamic and combustion-flow sensors based on laser absorption spectroscopy. In addition to conventional species concentration and density measurements, spectroscopic techniques for temperatu...
متن کاملField detection of CO and CH4 by NIR 2f modulation laser spectroscopy
A novel compact fiber-coupled NIR system based on a DFB diode laser source is employed as a portable and sensitive gas sensor for trace detection of combustion pollutant molecules. We demonstrate the performance of such an NIR gas sensor by tracing the absorption lines of CO and CH4 using 2f-WMS technique at moderate temperature of T ~ 600°C in the recuperator channel of an industrial furnace...
متن کاملDevelopment of a tunable mid-IR difference frequency laser source for highly sensitive airborne trace gas detection.
The development of a compact tunable mid-IR laser system at 3.5 micrometers for quantitative airborne spectroscopic trace gas absorption measurements is reported. The mid-IR laser system is based on difference frequency generation (DFG) in periodically poled LiNbO3 and utilizes optical fiber amplified near-IR diode and fiber lasers as pump sources operating at 1083 nm and 1562 nm, respectively....
متن کاملA Fast Room Temperature NH3 Sensor Based on an Al/p-Si/Al Structure with Schottky Electrodes
In this paper, an electrical-based NH₃ sensor with an Al/p-Si/Al structure is reported. The p-Si substrate is microstructured by fs-laser irradiation and then etched by 30% alkaline solution. This sensor works well at room temperature with fast response/recovery for NH₃ gas at 5-100 ppm concentration. However, when the sensor is annealed in N₂/H₂ forming gas or short-circuited for Al/Si electro...
متن کاملChirped Laser Dispersion Spectroscopy for Remote Open-Path Trace-Gas Sensing
In this paper we present a prototype instrument for remote open-path detection of nitrous oxide. The sensor is based on a 4.53 μm quantum cascade laser and uses the chirped laser dispersion spectroscopy (CLaDS) technique for molecular concentration measurements. To the best of our knowledge this is the first demonstration of open-path laser-based trace-gas detection using a molecular dispersion...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2001