Volume 15 Issue 5, May 2021

Photonics offers high hopes for next-generation neural network processors. Now it has been shown that even entirely using off-the-shelf photonics allows surpassing speed and energy efficiency of cutting-edge GPUs.

Optical acoustic sensors have gained interest for use in photoacoustic imaging systems, but can they dethrone conventional piezoelectric sensors altogether?

Progress in the field of quantum-photonics applications of metasurfaces is reviewed. Cutting-edge research, including the development of optical chips supporting high-dimensional quantum entanglement and advanced quantum tomography, is summarized.

An optical ultrasound sensor based on a CMOS-compatible split-rib waveguide is demonstrated, offering high sensitivity, broadband detection (measured 3–30 MHz), small size (20 μm) and scalability to a fine-pitch matrix.

Using CMOS-ready ultra-high-Q microresonators, a highly coherent electrically pumped integrated laser with frequency noise of 0.2 Hz² Hz⁻¹, corresponding to a short-term linewidth of 1.2 Hz, is demonstrated. The device configuration is also found to relieve the dispersion requirements for microcomb generation that have limited certain nonlinear platforms.

An intensity-based holographic imaging via space-domain Kramers–Kronig relations is presented, allowing the phase image of an object to be obtained directly from a single intensity measurement with oblique illumination.

A stimulated-emission-depletion-based fluorescence localization and super-resolution microscopy concept that is capable of attaining a spatial resolution down at the size scale of the fluorophores themselves and a localization precision of 1–3 nm in standard deviation is reported.

Linear diffractive structures are by themselves passive systems but researchers here exploit the non-linearity of a photodetector to realize a reconfigurable diffractive ‘processing’ unit. High-speed image and video recognition is demonstrated.

Two quantum repeater segments are connected via on-demand entanglement swapping by using two atomic quantum memories. The efficiency improves from a quadratic scaling to a linear one with the preparation efficiency of the atom–photon entanglement.

Fluoride-treated CsPbBr₃ nanocrystals emit light with near unity efficiency at temperatures of up to 373 K.

A structured-light-based detection of a particle trapped in optical tweezers enables ultrafast velocity and viscosity determination.

Composites of fluorescent metal–organic framework nanocrystals in a polymer are exploited to create fast scintillators with a rise time of about 50 ps.