Frequency-stabilized diode laser with the Zeeman shift in an atomic vapor

Abstract

We demonstrate a robust method of stabilizing a diode laser frequency to an atomic transition. This technique employs the Zeeman shift to generate an antisymmetric signal about a Doppler-broadened atomic resonance, and therefore offers a large recapture range as well as high stability. The frequency of a 780-nm diode laser, stabilized to such a signal in Rb, drifted less than 0.5 MHz peak-peak (1 part in 10(9)) in 38 h. This tunable frequency lock can be constructed inexpensively, requires little laser power, rarely loses lock, and can be extended to other wavelengths by use of different atomic species.

Observation and optimization of DAVLL spectra on the 1S0–3P1 transition of neutral mercury atom

“…balanced detection, the DAVLL spectra are obtained. We adopt AS as the frequency reference instead of saturated absorption spectroscopy (SAS) that was used in the DAVLL of rubidium [10], because the SAS of mercury atoms is almost indiscernible in a complete DAVLL line shape (3 GHz width).…”

“…The line shape with larger amplitude and slope is preferable, because the locked frequency can be insensitive to noise sources that cause the laser frequency drifting [10]. For a given probe power, the amplitudes and slopes of DAVLL signals are mainly influenced by the magnetic field and cell temperature.…”

“…To ensure frequency stability, the diode laser is locked at the atomic resonance transition, by modulating the laser frequency, such as frequency modulation spectra [7] and modulation transfer spectra [8,9]. Alternatively, modulation-free spectra, including DAVLL spectra [10,11], sub-Doppler DAVLL spectra [12] and polarization spectra [13][14][15], were developed in several decades.…”

“…First used in rubidium by Corwin et al [10], DAVLL is a spectroscopic method that generates dichroism in atomic media by an axial magnetic field. The absorption of sþ and sÀ components of the linearly polarized probe beam differs, due to energy splitting caused by the Zeeman effect.…”

Efficient technique for measuring laser frequency stability

“…A most efficient way to reduce frequency fluctuations is the locking of laser frequency to a reference frequency with an intrinsically high stability, such as an ultrastable high-finesse Fabry-Pérot, or, better, a narrow atomic resonance transition. In the past decades, many different experimental schemes were elaborated for locking DL frequencies to atomic resonance lines, such as saturated absorption [1,2], magneto-optical processes [3], including the technique of dichroic atomic vapor laser locking (DAVLL) [4][5][6][7], transversely-pumped thin cell spectroscopy [8], polarization spectroscopy [9], and selective reflection spectroscopy [10][11][12][13].…”