title: Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry incorporating an optical circulator.
abstract: To reduce the complexity of fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry, a system incorporating a fiber-coupled optical circulator to deflect the cavity-reflected light for laser stabilization has been realized. Detection near the shot-noise limit has been demonstrated for both Doppler-broadened and sub-Doppler signals, yielding a lowest detectable absorption and optical phase shift of 2.2×10(-12)  cm(-1) and 4.0×10(-12)  cm(-1), respectively, both for a 10 s integration time, where the former corresponds to a detection limit of C2H2 of 5 ppt.
authors.forename: Patrick
authors.initials: P
authors.lastname: Ehlers
authors.forename: Isak
authors.initials: I
authors.lastname: Silander
authors.forename: Junyang
authors.initials: J
authors.lastname: Wang
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Foltynowicz
authors.forename: Ove
authors.initials: O
authors.lastname: Axner