Achieving high energy resolution in spin systems is important for fundamental physics research and precision measurements, with alkali-noble-gas comagnetometers being among the best available sensors. We found a new relaxation mechanism in such devices, the gradient of the Fermi-contact-interaction field that dominates the relaxation of hyperpolarized nuclear spins. We report on precise control over spin distribution, demonstrating a tenfold increase of nuclear spin hyperpolarization and transverse coherence time with optimal hybrid optical pumping. Operating in the self-compensation regime, our ${}^{21}\mathrm{Ne}\text{−}\mathrm{Rb}\text{−}\mathrm{K}$ comagnetometer achieves an ultrahigh inertial rotation sensitivity of $3\times {10}^{-8}\mathrm{rad}/\mathrm{s}/{\mathrm{Hz}}^{1/2}$ in the frequency range from 0.2 to 1.0 Hz, which is equivalent to the energy resolution of $3.1\times {10}^{-23}{\mathrm{eV}/\mathrm{Hz}}^{1/2}$. We propose to use this comagnetometer to search for exotic spin-dependent interactions involving proton and neutron spins. The projected sensitivity surpasses the previous experimental and astrophysical limits by more than 4 orders of magnitude.

The momentum carried by structured light fields exhibits a rich array of surprising features. In this work, we generatetransverseorbital angular momentum (TOAM) in the interference field of two parallel and counter-propagating linearly-polarised focused beams, synthesising an array of identical handedness vortices carrying intrinsic TOAM. We explore this structured light field using an optomechanical sensor, consisting of an optically levitated silicon nanorod, whose rotation is a probe of the optical angular momentum, which generates an exceptionally large torque. This simple creation and direct observation of TOAM will have applications in studies of fundamental physics, the optical manipulation of matter and quantum optomechanics.

Photonics is currently undergoing an era of miniaturization thanks in part to two-dimensional (2D) optical metasurfaces. Their ability to sculpt and redirect optical momentum can give rise to an optical force, which acts orthogonally to the direction of light propagation. Powered by a single unfocused light beam, these lateral optical forces (LOFs) can be used to drive advanced metavehicles and are controlled via the incident beam’s polarization. However, the full control of a metavehicle on a 2D plane (i.e. forward, backward, left, and right) with a sign-switchable LOF remains a challenge. Here we present a phase-gradient metasurface route for achieving such full control while also increasing efficiency. The proposed metasurface is able to deflect a normally incident plane wave in a traverse direction by modulating the plane wave’s polarization, and results in a sign-switchable recoil LOF. When applied to a metavehicle, this LOF enables a level of motion control that was previously unobtainable.

Nanoparticles levitated by optical fields under vacuum conditions have applications in quantum science, the study of nanothermodynamics and precision sensing. The existing techniques for loading optical traps require ambient conditions and often involve dispersion in liquids, which can contaminate delicate optics and lead to enhanced optical absorption and heating. Here, we present a clean, dry and generic mechanism for directly loading optical traps at pressures down to 1 mbar, exploiting Laser Induced Acoustic Desorption and allowing for the rapid and efficient trapping of nanoparticles.

We report an ultrasensitive atomic spin sensor employing double spin resonance, achieving a spin signal enhancement of 2600 and a sensitivity of 0.57 fT/sqrt[Hz] under nonzero magnetic field measurements. Furthermore, we establish an in situ alkali-noble-gas spin sensor by tracing the measured spin precession frequency to the nuclear spins gyromagnetic ratio constant with high accuracy. The dominant systematic uncertainty induced by Fermi-contact interactions during the trace process has been suppressed by more than 2 orders of magnitude via pulsed train sequences. This Letter paves the way for achieving both ultrahigh sensitivity and traceability, offering promising opportunities for exploring new physics beyond the standard model and advancing quantum metrology in complex environments.