Abstract. Lidar is an effective tool for high-altitude atmospheric measurement in which
a weak absorption line for the target gas is selected to ensure a large
optical depth. The laser frequency stabilization to the line center is
required, and a sub-Doppler (sD) spectroscopy of the target line is preferred
as a frequency reference. In this paper, a novel universal sD noise-immune cavity-enhanced optical heterodyne molecular
spectroscopy
(NICE-OHMS)
instrumentation based on a fiber-coupled optical single-sideband
electro-optic modulator (f-SSM) for the potential application in atmospheric
lidar for different target gases with different types of lasers is reported.
The f-SSM can replace all frequency actuators in the system, so as to
eliminate the individual design of feedback servos that often are tailored
for each laser. The universality of the instrumentation was demonstrated by
the alternative use of either an Er-doped fiber laser or a whispering-gallery-mode laser. Then the instruments based on both lasers were used to produce
the sD signals of acetylene, which worked as a frequency reference to
stabilize the laser. By performing the lockings, relative frequency
stabilizations of 8.3×10-13 and 7.5×10-13 at
an integration time of 240 s were demonstrated.
Laser frequency stabilization based on an universal sub-Doppler NICE-OHMS instrumentation for the potential application in atmospheric Lidar
