What's Laser Absorption Spectroscopy？
Laser absorption spectroscopy is a technique used to measure the concentration of specific gases or molecules in a sample by analyzing the absorption of laser light as it passes through the sample. This method is highly sensitive and precise, making it valuable in a wide range of applications, including environmental monitoring, industrial process control, and fundamental scientific research.
How It Works:
Laser Source: A laser is chosen with a wavelength that corresponds to the absorption lines of the target molecule or gas. Different molecules absorb light at different wavelengths, so the laser is tuned to match these specific wavelengths.
Sample Interaction: The laser beam is directed through the sample, which can be in the form of a gas, liquid, or solid. As the laser light passes through the sample, molecules that resonate with the laser's wavelength absorb some of the light.
Detection: The light that emerges from the sample is measured using a detector. By comparing the intensity of the transmitted light with the initial intensity, the amount of light absorbed by the sample can be determined.
Data Analysis: The absorption data is analyzed to determine the concentration of the target molecule in the sample. This is based on the Beer-Lambert law, which relates the absorption of light to the concentration of the absorbing species.
Applications:
Environmental Monitoring: Measuring pollutants like carbon dioxide, methane, or other greenhouse gases in the atmosphere.
Medical Diagnostics: Non-invasive monitoring of gases in breath, such as detecting volatile organic compounds that may indicate diseases.
Industrial Processes: Monitoring gas concentrations in combustion processes, chemical reactions, or in semiconductor manufacturing.
Fundamental Research: Investigating molecular structures and dynamics by studying how molecules absorb light.
Laser absorption spectroscopy is favored for its high selectivity, sensitivity, and the ability to provide real-time, in situ measurements.