Light from a Nd:YAG laser at 1064 nm is independently stabilized to two Fabry–Perot etalons situated on separate vibration-isolation platforms. A heterodyne beat measurement shows their relative frequency stability to be at the part-in- 1015 level at 5 s and the relative linewidth to be less than 1 Hz.
© 2004 Optical Society of America
Stephen A. Webster, Mark Oxborrow, and Patrick Gill, "Subhertz-linewidth Nd:YAG laser," Opt. Lett. 29, 1497-1499 (2004)