Tittel, F.Lancaster, D.Richter, D.2010-08-112010-08-112000Laser Physics: international journal, 2000; 10(1):348-3541054-660Xhttp://hdl.handle.net/2440/59682The development of compact spectroscopic gas sensors and their applications to environmental sensing will be described. These sensors employ mid-infrared difference-frequency generation (DFG) in periodically poled lithium niobate (PPLN) crystals pumped by two single-frequency solid state lasers such as diode lasers, diode-pumped solid state, and fiber lasers. Ultrasensitive, highly selective, and real-time measurements of several important atmospheric trace gases, including carbon monoxide, nitrous oxide, carbon dioxide, formaldehyde [correction of formaldehye], and methane, have been demonstrated.enCopyright © 2000 by MAIK “Nauka /InterperiodicaJournal article003000115165157