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arXiv · 2404.01874

Laser mode-hopping assisted all-optical single beam pulsed atomic magnetometer

Ji Hoon Yoon·Sang Hyuk Hong·Taek Jeong·Sin Hyuk Yim·Kyu Min Shim·Sangkyung Lee
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Abstract

We demonstrate an all-optical single beam pulsed atomic magnetometer assisted by laser mode-hopping in a distributed Bragg reflector (DBR) laser. We implement a temporal sequence of the laser current, with sinusoidal current modulation including the laser mode-hop current for synchronous optical pumping, and a following constant current for paramagnetic Faraday rotation measurements, to probe the free induction decay (FID) of transverse $^{87}$Rb spin polarization. Repetitive sudden frequency shifts of 20 GHz around the pressure-broadened $^{87}$Rb spectra, originating from laser mode-hopping, enable discontinuous optical pumping modulation with a large depth, which enhances transverse spin polarization. We achieved a sensitivity of 0.6 pT/Hz$^{1/2}$ in a magnetic field of 27 $\mu$T, mainly limited by the photon-shot-noise and the magnetic field noise induced by the current noise in the current supply for driving the bias magnetic field coil. The Cramer-Rao lower bound (CRLB) of the sensitivity due to the non-magnetic noise such as photon shot-noise is 131 fT/Hz$^{1/2}$. Our approach based on laser mode-hopping can be applied for the miniaturization of all-optical atomic magnetometers with sub-pT/Hz$^{1/2}$ sensitivities.

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Ji Hoon Yoon, Sang Hyuk Hong, Taek Jeong, Sin Hyuk Yim, Kyu Min Shim, Sangkyung Lee. 2024-04-02. Laser mode-hopping assisted all-optical single beam pulsed atomic magnetometer. https://arxiv.org/abs/2404.01874

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