Frequency reference for laser spectroscopy with the stabilized 4-m-long Fabry–Perot cavity

Abstract

A 4-m-long, stabilized Fabry–Perot interferometer for frequency reference in high-resolution laser spectroscopy is described. The interferometer works as a transfer cavity locked to one laser whose frequency is Doppler-free stabilized to an atomic transition. Another laser beam whose frequency is scanned across the investigated spectral range is transmitted across the cavity to yield the frequency markers with FSR intervals below 40 MHz. The two laser beams of very close frequencies are separated at the cavity exit by a polarization method. The described methodology is simple yet versatile and provides dense and stable frequency markers for high-resolution laser spectroscopy.