arXiv subjects

Riaan P. Schmidt

Publications and source records attributed to Riaan P. Schmidt.

2 recordsLinked to original sources

arXiv2026

Spatio-spectral vector light created by optical activity in rubidium vapor

We show that optical activity in atomic media can generate multidimensional correlations in frequency, polarization and spatial degrees of freedom, allowing us to observe frequency shifts as image rotations. Specifically, we demonstrate a pump-probe scheme, where optical pumping with circularly polarized light generates macroscopic magnetization in an atomic vapor, associated with frequency-dependent circular dichroism and birefringence. A vortex probe beam, characterized by spatially varying polarization, maps this optical activity onto the spatial structure of the transmitted light. Measuring the intensity profile in a suitable polarization component then allows us to perform spatially resolved polarization spectroscopy. On resonance we observe a rotation with a slope in the order of 98 mrad per MHz. These findings may find applications in image-based laser-locking, high-precision spectroscopy, magnetometry, and the generation of hybrid entanglement.

physics.atom-ph↗

arXiv2024

Interaction of vector light beams with atoms exposed to a time-dependent magnetic field

During recent years interest has been rising for applications of vector light beams towards magnetic field sensing. In particular, a series of experiments were performed to extract information about properties of static magnetic fields from absorption profiles of light passing through an atomic gas target. In the present work, we propose an extension to this method for oscillating magnetic fields. To investigate this scenario, we carried out theoretical analysis based on the time-dependent density matrix theory. We found that absorption profiles, even when averaged over typical observation times, are indeed sensitive to both strength and frequency of the time-dependent field, thus opening the prospect for a powerful diagnostic technique. To illustrate this sensitivity, we performed detailed calculations for the $5s \;\, {}^2S_{1/2}$ ($F=1$) $-$ $5p \;\, {}^2 P_{3/2}$ ($F=0$) transition in rubidium atoms, subject to a superposition of an oscillating (test) and a static (reference) magnetic field.

physics.atom-ph↗