The interaction between cylindrical vector beams and atoms under a weak magnetic field induces spatially dependent electromagnetically induced transparency (EIT). Based on this coherence effect, we investigated the relationship between the magnitude and orientation of the transverse magnetic field (TMF) and the spatial intensity distribution of cylindrical vector beams passing through a thermal atom ensemble, which is intuitively manifested in polarization selection absorption. The radially polarized beam exhibits a spatial axisymmetric polarization structure. When a TMF is applied, transparent regions in the transmitted beam strongly correlate with the beam’s polarization distribution. Variations in the TMF magnitude alter the absorption of specific polarization components by the atomic system, thereby affecting the local transmittance. This enables the TMF magnitude to be inferred from the single transmittance of the intensity pattern. The alignment of the TMF orientation is reflected in the rotation of the petal-shaped transmission patterns aligned with the mirror axis. Theoretical solutions using optical Bloch equations reveal this specific spatially dependent EIT is closely related to the transverse relaxation rate between the ground state energy levels. Experimental data align perfectly with the theoretical results, suggesting potential applications in light field manipulation and magnetic field measurement.
Quantum microwave photonics (QMWP) is an innovative approach that combines energy–time entangled biphoton sources as the optical carrier with time-correlated single-photon detection for high-speed radio frequency (RF) signal recovery. This groundbreaking method offers unique advantages, such as nonlocal RF signal encoding and robust resistance to dispersion-induced frequency fading. We explore the versatility of processing the quantum microwave photonic signal by utilizing coincidence window selection on the biphoton coincidence distribution. The demonstration includes finely tunable RF phase shifting, flexible multitap transversal filtering (with up to 14 taps), and photonically implemented RF mixing, leveraging the nonlocal RF mapping characteristic of QMWP. These accomplishments significantly enhance the capability of microwave photonic systems in processing ultraweak signals, opening up new possibilities for various applications.
Based on frequency entangled sources and arrival time measurements, a best time synchronization stability result of fewer than 100 fs has been reported over 20km fiber links, verifying the superiority of quantum time synchronization. In this paper, a two-way quantum time transfer over 50 km fiber links with the same frequency standard was implemented, with a short-term stability of 2.63 ps at an averaging time of 18 s and a long-term stability of 79.2 fs at 73700 s. The system accuracy in terms of the 50km fiber transfer length is measured as 524.75 ps, the agreement of which with the theoretical simulation illustrates that improving the spectral consistency of the two entangled sources will significantly improve the accuracy. This result shows that the fiber-optic two-way quantum time transfer can be successfully extended to a metropolitan fiber link distance of around 50 km or longer, not only maintaining the transfer stability well below picosecond but also promising further improvements in synchronization accuracy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.