New evidence shows melt ponds in the northern parts of the Arctic may be biological sources of ice-nucleating particles, a key ingredient for cloud formation that has been largely overlooked.

Controlling photon spin, or the handedness of light, is useful for storing and transmitting information. However, generating circularly polarized light typically requires complex or chiral structures. Researchers from the Tokyo University of Science show that hitting a gold nanorod slightly off-center with an electron beam causes the light around it to rotate. This method offers a simpler way to control photon spin and could accelerate the development of smaller, more efficient optical and quantum devices.

Existing quasi-BIC architectures typically face a fundamental trade-off between high quality (Q) factors and wide-angle chiral operation. Scientists have now developed a planar dielectric metasurface that overcomes this by harnessing net zero topological charge (ZTC) merging BICs. This design simultaneously delivers a high Q-factor (~10⁴), near-perfect linear and nonlinear circular dichroism (0.99/0.999), and exceptional angular robustness—all on a fabrication-friendly, single-layer platform.