Proof of the feasibility of a nanocell-based wide-range optical magnetometer

Abstract

We present an experimental scheme performing scalar magnetometry based on the fitting of Rb D 2 line spectra recorded by derivative selective reflection spectroscopy from an optical nanometric-thick cell. To demonstrate its efficiency, the magnetometer is used to measure the inhomogeneous magnetic field produced by a permanent neodimuim-iron-boron alloy ring magnet at different distances. The computational tasks are realized by relatively cheap electronic components: an Arduino Due board for the external control of the laser and acquisition of spectra, and a Raspberry Pi computer for the fitting. The coefficient of variation of the measurements remains under 5% in the magnetic field range of 40 -200 mT, limited only by the size of the oven and translation stage used in our experiment. The proposed scheme is expected to operate with a high measurement precision also for stronger magnetic fields (> 500 mT), in the hyperfine Paschen-Back regime, where the evolution of the atomic transitions can be calculated with a high accuracy.

Nanostructured Alkali-Metal Vapor Cells

“…The combination of these features with high-NA lateral resolution and the ultra-thin extent of the atoms makes our nanocell a powerful, spatially selective sensing tool. A special example of current interest in sensing is magnetometry with nanoscale resolution [18], and indeed sensitive magnetometry has recently been demonstrated using nanocells [15]. Our chip and measurement platform allows for improved spatial selectivity and high lateral resolution, especially for probing magnetic fields close to surfaces.…”

“…Individual atoms or atomic ensembles offer an attractive platform for quantum sensing and devices. Atom-light interactions have already found use in applications such as clocks [1,2], optical filtering [3][4][5], magnetometry [6][7][8][9][10][11][12][13][14][15], and laser stabilization [16,17]. However, most atomic devices are either macroscopic or at best mesoscopic [9].…”

“…As well as the fundamental interest in atom-light interactions at the nanoscale already highlighted, there is also interest in interfacing thermal vapors with nanophotonics [55][56][57][58] and integrated opto-mechanical features [59]. However, much work remains to be done before nanometer-scale vapor-based devices can be used in technological applications, e.g., for local sensing [15] or quantum networks [36,60]. In particular, reliable fabrication methods are needed for the realization of scalable and efficient platforms.…”

Sub-Doppler spectra of sodium $D$ lines in a wide range of magnetic field: theoretical study

“…Magneto-optical phenomena in alkali metal vapors are of particular interest. Complete understanding of various magneto-optical effects occurring in alkali vapors [8] is important since they are widely used, for example in fundamental and applied studies of electromagnetically induced transparency [9,10], Faraday filters [11,12], optical magnetometry [13], laser-frequency locking [14] and elsewhere. Such phenomena often rely on the peculiarities of the behavior of Zeeman transitions, so that frequency separation of individual transitions is of high importance.…”

“…This allows to observe the appearance of several peculiarities, such as Guiding Transitions (GT) and two different types of so-called Magnetically-induced Circular Dichroism (MCD) [19,20]. Moreover, several efficient techniques have been developed to enhance a spectral visibility of Zeeman transitions while preserving their relative probability scaling, such as derivative of Selective Reflection (dSR) [13,21] and Second Derivative of absorption (SD) [22][23][24].…”