Related Experiment Video
Updated: Aug 7, 2026

09:40
Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown
Published on: February 14, 2014
[The study of remote sensing CH4 concentration based on tunable diode laser absorption spectroscopy]
Shi-Mei Wang1, Wen-Qing Liu, Jian-Guo Liu
1Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
Guang Pu Xue Yu Guang Pu Fen Xi = Guang Pu
|July 11, 2006
Summary
This study details a methane (CH4) remote sensing system using tunable diode laser absorption spectroscopy. The system successfully measured CH4, laying groundwork for online monitoring applications.
Area of Science:
- Spectroscopy
- Laser Technology
- Environmental Monitoring
Context:
- Direct absorption spectroscopy and modulation spectroscopy principles are reviewed.
- Tunable diode laser (TDL) technology is applied for gas sensing.
- Methane (CH4) detection is crucial for environmental and industrial applications.
Purpose:
- To design and analyze a remote sensing system for methane (CH4) detection.
- To investigate the application of near-infrared tunable diode lasers for CH4 measurement.
- To evaluate signal-to-noise ratios and identify fundamental noise sources.
Summary:
- A near-infrared tunable diode laser system operating at 1.65 microm was developed for CH4 measurement.
- The R(6) line of the 2upsilon3 band of methane was utilized for detection.
- The system's performance, including signal-to-noise ratio and noise factors, was analyzed.
Impact:
- Provides a foundation for developing online remote sensing systems for methane (CH4).
- Demonstrates the efficacy of TDL spectroscopy for precise gas analysis.
- Contributes to advancements in environmental monitoring and industrial process control.
Related Concept Videos
UV–Vis Spectrometers
The absorbance of UV and visible (UV–visible) radiations is measured using a UV–visible spectrophotometer. Deuterium lamps, which emit UV radiation, and tungsten lamps, which produce radiation in the visible region, are used as light sources in UV–visible spectrophotometers. A monochromator or prism is used for diffraction grating, i.e., to split the incoming radiation into different wavelengths. A system of slits is used to focus the desired wavelength on the sample cell. Samples for...
UV–Vis Spectroscopy: Beer–Lambert Law
The Beer-Lambert law describes the relationship between absorbance and concentration, which combines the principles established by scientists Johann Heinrich Lambert and August Beer. Lambert's law states that when light passes through a medium, the loss in intensity is directly proportional to the original intensity and the path length of the light. Beer's law proposed that the transmittance of a solution remains constant if the product of concentration and path length is constant. The modern...
Raman Spectroscopy: Overview
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
UV–Vis Spectroscopy of Conjugated Systems
Organic compounds with conjugated double bonds show strong absorption features in the UV–visible region of the electromagnetic spectrum attributed to π → π* electronic excitations. Generally, a UV–vis absorption spectrum is recorded as a plot of absorbance vs wavelength. The wavelength of maximum absorbance, which manifests as a peak in the absorption spectrum, is denoted as λmax.
One of the factors influencing λmax is the extent of conjugation in the...
One of the factors influencing λmax is the extent of conjugation in the...

