Volume 18 Issue 1, January 2024

A coherent microwave-to-optical conversion scheme, previously feasible only under cryogenic environments, has now been expanded to ambient conditions by using Rydberg atoms.

One-way light transmission can be realized by embracing, rather than mitigating, thermal effects in carefully engineered metasurfaces.

Ultracold atoms provide a platform for realizing the temporal analogue of Snell’s law.

Acoustic modulation of atmospheric air enables the deflection of laser pulses with a peak power of 20 gigawatts, expanding the acousto-optics toolbox to high-power laser manipulation in ambient air.

With many exotic electromagnetic effects, metamaterials are now being exploited in real-world biomedical applications, with expected impacts in healthcare.

Advances in the understanding of optical skyrmions, within a unified topological framework, are reviewed. The field structure of such optical quasiparticles, and their topological characteristics, may be useful for fields ranging from imaging to quantum technologies.

Optical second-harmonic waves are generated from the electric quadrupole contribution in a centrosymmetric magnetic Weyl semimetal Co₃Sn₂S₂. Two magnetic orders and phase transitions are explored in temperature-dependent rotational anisotropy measurements by second-harmonic generation.

Continuous-wave conversion of a 13.9 GHz field to a near-infrared optical signal is demonstrated by using Rydberg atoms at room temperature. The conversion bandwidth is 16 MHz and the conversion dynamic range is 57 dB, descending down to 3.8 K noise-equivalent temperature.

A new conceptual approach to light generation involving an ensemble of light-emitting charges may result in more compact superradiant light sources.

By exploiting the nonlinear Raman gain inherent in fused silica, short sub-100-fs dissipative Raman soliton pulses can be formed in fused-silica fibre resonators that are driven by electro-optically generated picosecond pulses.

Air-based acousto-optic modulation is shown to be able to efficiently control gigawatt-scale, ultrashort laser pulses.

Integrating multiple silicon waveguides with black phosphorus enables the realization of a variety of optoelectronic logic gates operating at 1.55 μm.

Time reflection and refraction are experimentally observed in ultracold atoms. To this end, the time boundary is formed by imposing an abrupt change in the coupling strength of the atomic chain. Time boundary effects are robust against material disorder.

An electrically tunable device that can work as an optical switch, an optical limiter with a tunable limiting threshold and a nonlinear optical isolator with a tunable operating range in the mid-infrared range is realized by combining a gold layer with subwavelength square slits and a layer of VO₂.

Bias-free optical metasurfaces with a large non-reciprocal response for free-space radiation are discussed, based on thermo-optic nonlinearities. These ultrathin devices may lead to new approaches for areas ranging from signal processing to protection of high-power laser cavities.

Three-dimensional nonlinear optical metamaterials are realized by directly engineering the symmetries of electronic wavefunctions at the atomic scale by stacking individual two-dimensional van der Waals interfaces into a precisely designed three-dimensional configuration.

A new form of chirped amplification with two different nonlinear crystals can generate high-energy, single-cycle laser pulses with terawatt-level peak powers.