Spintronic terahertz emitters (STEs) are desirable broadband terahertz sources, but their limited signal strength has hindered practical application. By optimizing the photonic and thermal environment, the authors present an STE that could overcome this obstacle. Benchmarking against the state-of-the-art terahertz emitters based on optical rectification, this STE delivers strong terahertz pulses with comparable peak electric field and fluence, and offers additional features such as broadband radiation, easy alignment, and rotation of the terahertz polarization plane without power loss. This work will open up a promising pathway to nonlinear terahertz spectroscopy with spintronic sources.

• Optics
• Photonics
• Spintronics

A low-frequency radar method with improved resolution could aid in the detection of landmines and archeological objects.

The LIGO experiment has demonstrated a noise-squeezing technique for its entire frequency-detection range—a feat that could boost the detection rate of black hole mergers by up to 65%.

• Gravitation
• Optics
• Quantum Physics

Illuminating a high-resolution lens with waves whose intensity diminishes over time can improve the image quality.

• Acoustics
• Metamaterials
• Photonics

A new interpretation of high-harmonic generation—the cornerstone of attosecond physics—paves the way for quantum applications of this process.

Light–matter interactions in certain one-dimensional photonic materials can bring light nearly to a standstill, an effect that researchers show requires consideration of long-range interactions between the material’s components.

Reading out the state of a quantum system at low temperature is generally challenging, as weak quantum signals must be amplified while adding as little noise as possible. Also, some qubit types rely on external magnetic fields and require magnetic-field-compatible superconducting parametric amplifiers. Here an innovative amp design leverages the nonlinear response of the gate-tunable kinetic inductance of proximitized semiconducting nanowires. The tunability allows integration with superconducting quantum systems, thanks to minimal crosstalk, and this amp can work with semiconductor-based spin qubits and other hybrid systems in magnetic fields of 500 mT.

• Optoelectronics
• Quantum Information
• Superconductivity

Light-field microscopy (LFM) extracts volumetric data from a specimen by simultaneously capturing the positional and angular information of light rays emanating from the sample. While conventional LFM requires a compromise between depth of field (DOF) and resolution, this work introduces a quantum approach to eliminate this compromise by harnessing position-momentum entanglement of photon pairs. Compared to conventional LFM at the same resolution, the quantum approach can yield up to tenfold improvement in DOF. This work illustrates the power of utilizing multidimensional entanglement in microscopy and hopefully will inspire further innovations in the field.

• Biological Physics
• Optics
• Quantum Physics

Researchers have determined the amount of transverse orbital angular momentum that a type of optical vortex carries per photon, an important step for future applications.

• Interdisciplinary Physics
• Optics
• Photonics

A new model refines an optical microscopy technique, allowing for micrometer-scale discrimination of key protein types and their organization in mammalian biological tissues.

• Biological Physics
• Optics