Noise suppression in coherent population-trapping atomic clock by differential magneto-optic rotation detection

Abstract

We propose and investigate a scheme for differential detection of the magneto-optic rotation (MOR) effect, where a linearly polarized bichromatic laser field is coherent population-trapping (CPT)-resonant with alkali atoms, and discuss the application of this effect to CPT-based atomic clocks. The results of our study indicate that laser noise in a vertical cavity surface-emitting laser-based CPT atomic clock can be effectively suppressed by the proposed scheme. The proposed scheme promises to realize a packaged MOR-CPT atomic clock that has significantly better frequency stability coupled with similar power consumption, volume, and cost when compared with currently available packaged CPT atomic clocks.

Coherent population trapping magnetometer by differential detecting magneto–optic rotation effect

“…Another characteristic of the DMOR curve is that the m 1 + m 2 = 0 CPT signal is approximately one order weaker than that of m 1 + m 2 = ±2, and its amplitude and linewidth are sensitive to B. [19] We also frequency modulate the microwave at 1 kHz and obtain the differential style lock-in CPT signal using a lock-in amplifier. According to Fig.…”

“…[18], and we have studied a differential magnetooptic rotation (DMOR) atomic clock scheme that uses linearly polarized multi-chromatic light to interact with 87 Rb atoms. [19] Based on this scheme, we also experimentally study the DMOR CPT magnetometer scheme. The research results are given below.…”

Characterization of frequency stability in electromagnetically induced transparency-based atomic clocks using a differential detection scheme

“…Hence, when differential detection is performed using two outputs of an optical polarizer placed at 45 • with respect to the original polarization direction, a sharper resonant feature is expected when the modulation frequency is equal to the hyperfine splitting, ω 1 − ω 2 = ∆ hf . In addition, MOR detection schemes have demonstrated reduced intensity noise when compared to traditional EIT detection schemes [1,10]. Here, we show the first (to our best knowledge) experimental comparison of the frequency stabilities of EIT-and MOR-stabilized atomic clocks under different levels of laser noise and microwave oscillator noise.…”

“…Traditionally, this method determines the frequency between hyperfine states of an alkali metal atom via the change in transmitted intensity of a bichromatic optical field. However, recently it has been proposed that a modified detection scheme sensitive to the changes in the light polarization due to magneto-optical rotation (MOR) may increase the performance of such frequency measurements [1,9,10]. In this paper, we experimentally compare two detection schemes (traditional intensity-based EIT and polarization-rotation-sensitive MOR).…”

Transit Ramsey EIT resonances in a Rb vacuum cell

“…Many EIT-based measurements suffer from the residual intensity noise, especially if broad-band lasers, such as VCSELs, are used to excite optical transitions [27]. Several differential EIT schemes, e.g., based on magneto-optical rotation [28][29][30][31] or polarization selection rules [32], have been proposed recently to suppress the common-mode intensity noise while maintaining high-contrast EIT resonant features.…”