摘要
Ultrastable continuous-wave lasers are one of the important elements for space-based gravitational wave detection.Here we present a Pound–Drever–Hall laser frequency-locked system based on a field-programmable gate array,demonstrating its potential to achieve 10-16levels of frequency stability for space applications.The system is employed to lock a spacequalified 1064-nm neodymium-doped yttrium aluminum garnet laser to a laboratory-operated 20-cm ultrastable optical cavity.Major noise contributors are identified as laser intensity fluctuation and residual amplitude modulation.The heterodyne beat measurement shows that the frequency noise spectral density of a single laser is reduced to 2.5 Hz/√Hz at a Fourier frequency of 1 m Hz,and the frequency instability is 2.1×10^(-16)at 1 s and remains below 3.5×10^(-16)up to 6000 s.
基金
supported by the National Key Research and Development Program of China(Nos.2021YFC2201800 and 2020YFC2200300)
the National Natural Science Foundation of China(Nos.11327407,11654004,and 11235004)
the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDB21010300 and XDB23030202)。
