Continuous-wave difference-frequency generation based on BaGaSe crystal.

A continuous-wave mid-infrared radiation from difference frequency generation by mixing a continuous-wave Ti: sapphire laser and a continuous-wave YAG laser in a 15 mm long BaGaSe crystal is demonstrated for the first time. The tunable range from 3.15 to 7.

[Study on the Technology of the 4.4 μm Mid-Infrared Laser Heterodyne Spectrum].

In this paper, first time as our knowledge, we describe the development and performance evaluation of a 4.4 μm external cavity quantum cascade laser based laser heterodyne radiometer. Laser heterodyne spectroscopy is a high sensitive laser spectroscopy technique which offers the potential to develop a compact ground or satellite based radiometer for Earth observation and astronomy.

[Measurement and application of CO2 spectroscopic parameters near 2.0 μm].

The accuracy of absorption spectral parameters is very important for the trace gas measurement based on absorption spectroscopy techniques, especially for the isotopic abundance measurement of gas molecules. For some of the applications, spectral parameters listed in HITRAN database were used to retrieve the trace gas concentration. However, these parameters have uncertainty, in order to validate spectroscopic parameters near 2.

[Development of a photoacoustic spectroscopy system for the measurement of absorption coefficient of atmospheric aerosols].

In the present paper, the authors focus on the effect of the resonance frequency shift due to the changes in temperature and humidity on the PA signal, present several methods to control the noise derived form gas flow and vibration from the sampling pump. Based on the efforts mentioned above, a detection limit of 1.4 x 10(-8) W x cm(-1) x Hz(-1/2) was achieved for the measurement of atmospheric aerosols absorption coefficient.

[Design of a controllable low temperature cell and application].

A new cryogenic cell was developed and could operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than +/- 1 K. The structure and performance of the cryogenic cell was given in detail and the temperature stability of the sample cell was evaluated. The methane low temperature absorption spectra at 1.

[Research on vehicle-based remote sensing of natural gas pipeline leakage].

In the present paper the authors designed a vehicle-based remote sensing system using simulated platform and presented a new method of concentration calibration of natural gas pipeline leakage remote sensing. By investigating the performance of different distance, different material, different angle of topographic back scatter and different scan speed, a good coincidence was achieved between experimental results and theoretical results. The system can realize the remote detection of low-level methane concentration at a velocity of 53.

[Research on high resolution spectrum measurements of methane at 1.65 microm].

The high resolution spectrum of methane was obtained around 1.65 microm using a tunable DFB diode laser with a long adjustable optical path white * cell (46.36-1 158.

[The measurement of water vapor isotope based on mid-infrared difference frequency generation].

Stable-isotope ratio analysis of water is an important tool for geology, meteorology, and earth sciences. Measurements of water vapor isotopes are very helpful to explaining stratospheric aridity and related issues in atmospheric sciences. The absorption of water vapor near 2.

[Difference-frequency generation in PPLN and water vapor detection in air].

The continuously tunable laser source has been realized in a periodically poled LiNO3 crystal based on difference frequency generation and quasi-phase-matching technique. The pump laser is an 1 W tunable Ti: Sapphire laser with a tunable region from 770 to 870 nm. The signal laser is an 1 W diode-pumped monolithic Nd : YAG laser.

[Study on remote sensing of methane leakage using a tunable diode laser].

The leak of natural gas is not only an economic loss, but also the fountain of danger. Conventional detection techniques of natural gas pipe leak have low efficiency and slow respond time, therefore, it is difficult for them to suit practice application. Optical sensors based on NIR tunable diode laser absorption spectroscopy were widely used because of high sensitivity, small volume and less maintenance.