Atomic Compass: Detecting 3D Magnetic Field Alignment with Vector Vortex Light

Abstract

We describe and demonstrate how 3D magnetic field alignment can be inferred from single absorption images of an atomic cloud. While optically pumped magnetometers conventionally rely on temporal measurement of the Larmor precession of atomic dipoles, here a cold atomic vapour provides a spatial interface between vector light and external magnetic fields. Using a vector vortex beam, we inscribe structured atomic spin polarisation in a cloud of cold rubidium atoms, and record images of the resulting absorption patterns. The polar angle of an external magnetic field can be deduced with spatial Fourier analysis. This effect presents an alternative concept for detecting magnetic vector fields, and demonstrates, more generally, how introducing spatial phases between atomic energy levels can translate transient effects to the spatial domain.

Three-laser coherent population trapping in a multi-lambda system: theory, experiment and applications

“…For this application we take advantage of the fact that the shape, position, and strength of the dark resonances that appear in a spectrum strongly depend on the relation between the polarization of the beam and the magnetic field direction. Thus, the observed spectra provides information of the 3D polarization of the electric fields of the intervening beams, similarly to the recent demonstration of the measurement of the 3D magnetic field alignment using an atomic cloud and a vector vortex beam [33]. Here, as the typical size of the wavepacket of a trapped ion is in the 10 − 100 nm range, it can be used as a 3D polarimeter with spatial resolution below the diffraction limit of strongly focused beams, allowing to map the polarization distribution of focused beams.…”

Laser spectroscopy of hot atomic vapours: from ’scope to theoretical fit

“…4 and B.5 in [71], for example, list the wavelength and natural linewidth for the D 1 and D 2 transitions, respectively, for the alkali metals Na, K, Rb and Cs. Using equation (19) for the absolute matrix element, and equation (15) for the relative linestrengths allows us to calculate the absorption spectrum for all of the components in both D 1 and D 2 transitions using the total susceptibility of equation (13).…”

“…Many of the work-horse techniques of contemporary atomic physics experiments were first demonstrated in hot vapours, such as: coherent population trapping [1]; electromagnetically induced transparency [2]; and slow light [3]. Important experimental breakthroughs were also demonstrated with hot vapours, such as: the demonstration of quantum memory for light [4][5][6]; continuous-variable entanglement [7]; quantum metrology with nonclassical states of atomic ensembles [8]; realising fluids of light [9,10]; deterministic quantum teleportation between distant atomic objects [11]; orbital angular momentum transfer [12][13][14][15][16]; coherent frequency up-conversion [17,18]; an atomic compass [19,20]; and photon diffusion [21][22][23][24][25].…”

Generation and Manipulation of Spin‐Orbit Coupling mode via Four‐Wave Mixing with Quantum Interference

“…Most of the relevant works on nonlinear generation and manipulation of SOC light fields rely on a linear superposition of the orthogonal polarization components, which are separately generated by two scalar nonlinear processes in an interferometer [37][38][39][40][41][42][43] or a twocrystal-sandwich configuration. [44][45][46] Remarkably, exploring the vectorial nonlinear interactions driven directly by SOC light from 2D structure to 3D polarization Möbius strip, [47][48][49][50][51][52] has recently introduced a range of fascinating optical phenomena and functionalities, such as superresolution interferometric metrology, [53] designable light filaments [54,55] as well as controllable distortion of polarization and spatial profile. [56,57] Vectorial nonlinear optics offers a new platform for nonlinear control of SOC light as well as control of nonlinear processes by SOC light.…”