Novel diode laser-based sensors for gas sensing applications

The development of compact spectroscopic gas sensors and their applications to environmental sensing will be described. These sensors employ mid-infra red difference-frequency generation (DFG) in periodically poled lithium nio bate (PPLN) crystals pumped by two single-frequency solid state lasers such as diode lasers, diode-pumped solid state, and fiber lasers. Ultrasensitiv e, highly selective, and real-time measurements of several important atmosp heric trace gases, including carbon monoxide, nitrous oxide, carbon dioxide , formaldehye, and methane, have been demonstrated.