January 3, 2022
Laser stability is critical for sensing low concentrations of harmful gases in the air. Wavelength’s low noise laser diode driver, the WLD3343, can precisely deliver 500 mA of current to the laser diode without any heat dissipation accessories required and has the convenient option for voltage-controlled setpoint to further protect the laser. Because each study used some form of modulation, the initial sinusoidal or sawtooth signal was sent to the laser driver to modulate the output current to the laser.
For stable output power and accurate wavelength scanning with repeatable results, researchers used Wavelength Electronics’ WTC3243 temperature controller to control the laser temperature with stability better than 0.0009ºC. The benefits of the temperature controller can also help narrow linewidth and can ensure stable wavelength.
Now Available. CS-LDTC09: Ammonia Gas Detection With Laser Absorption Spectroscopy for Livestock
Gas emissions from large-scale livestock facilities increase directly with operation growth due to animals’ breath, waste fermentation, and the physical decomposition of the waste.
Researchers from China have developed a laser absorption spectrometer for high precision ammonia gas detection in livestock and poultry housing. Two different techniques are discussed: Open path laser absorption spectroscopy (OPLAS) and tunable diode laser absorption spectroscopy (TDLAS). Both provide support for precision air quality detection and control for this application. TDLAS achieves ammonia detection concentrations of lower than 5 ppm using harmonic absorption signals in the long path gas absorption well with total path length traveled for the light around 4.3 m. Laser absorption spectroscopy has similar results to other gas detection methods, while providing rapid and precise gas detection in portable systems.