Ultra-Narrow Laser for Optical Frequency Reference

Abstract

We present ultra-narrow line width, tunable diode laser system which will be used as a local oscillator in an optical atomic clock and for precision spectroscopy of Sr near 689 nm. Design of the high nesse optical cavity used as short-term frequency reference is optimized with respect to insensitivity to vibrations. We achieved laser line width of about 8 Hz, measured by comparison of two identical systems. The relative phase lock of two lasers is better than 150 mHz. Laser tunability and usefulness for precison spectroscopy were demonstrated through line shape measurement of a 20 kHz wide resonance of the optical cavity.

Strontium optical lattice clocks for practical realization of the metre and secondary representation of the second

“…The design of the cavity and the 689 nm laser system is described in details in Ref. [25]. In short, the Pound-Drever-Hall (PDH) locking scheme [26] is used to narrow the laser line width well below the width of the 1 S 0 -3 P 1 transition.…”

Low-pressure line-shape study in molecular oxygen with absolute frequency reference

“…It has allowed determination of absolute frequencies of Dopplerlimited optical transitions with accuracy of 1.2 MHz 27 or even 9 kHz. 28 Here we present a new improved experimental system based on the CRDS spectrometer linked to the OFC via the ultra-narrow (UN) laser 29 which enables determination of the absolute frequency at each point of recorded spectra, which was not possible with our earlier system. 27 The new setup also enables to obtain a higher accuracy of resulting line-shape parameters.…”

Dual Hg-Rb magneto-optical trap

“…The UV laser frequency is stabilized to the narrow (7.5 kHz) | 1 S 0 → | 3 P 1 transition in Sr by a stability transfer from an ultra-stable laser [64,65]. The ultra-stable laser is a part of an optical strontium lattice clock [66].…”