OH sensor based on ultraviolet, continuous-wave absorption spectroscopy utilizing a frequency-quadrupled, fiber-amplified external-cavity diode laser

摘要

The development of an all-solid-state cw laser system for optical absorption measurements of the OH radical in the UV spectral range is described. The tunable output of a 1064-nm external-cavity diode laser is amplified by use of a Nd:doped, double-clad fiber amplifier. The amplified near-IR radiation is frequency doubled by a periodically poled lithium niobate crystal and then quadrupled in a beta-barium borate crystal. The design and operation of the system and measurements of OH absorption in the (2,0) band of the A~(2)Σ~(+)-X~(2)II electronic transition are discussed.