Miniaturized optical frequency reference for next-generation portable optical clocks
Vincent Maurice, Zachary L. Newman, Susannah Dickerson, Morgan Rivers, James Hsiao, Phillip Greene, Mark Mescher, John Kitching, Matthew T. Hummon, Cort Johnson
Abstract
Optical frequency standards, or lasers stabilized to atomic or molecular transitions, are widely used in length metrology and laser ranging, provide a backbone for optical communications and lie at the heart of next-generation optical atomic clocks. Here we demonstrate a compact, low-power optical frequency reference based on the Doppler-free, two-photon transition in rubidium-87 at 778 nm implemented on a micro-optics breadboard. Our optical reference achieves a fractional frequency instability of 2.9×10 −12 / <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msqrt> <mml:mi>τ</mml:mi> </mml:msqrt> </mml:math> for averaging times τ less than 10 3 s, has a volume of ≈35 cm 3 and operates on ≈450 mW of electrical power. The advanced optical integration presented here demonstrates a key step towards the development of compact optical clocks and the broad dissemination of SI-traceable wavelength references.