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Researchers demonstrate a new way to create chiral nanostructures using a laser beam. By carefully controlling the direction of the laser beam's vibrations, the researchers created a variety of chiral structures made of platinum oxide in unique shapes, like twisted micropillars and spiral superstructures.
Near-infrared photodetectors play a significant role in many aspects of research and daily life and twisted-angle-induced unusual electrical and optical properties in van der Waals homostructures have received extraordinary attention recently. However, these emerging properties have rarely been applied to optoelectronic devices. Here, researchers demonstrate broadband photoresponse capable of overcoming the band-gap limitation of semiconductors in the twisted lead iodide homostructures.
Artificially engineered chiral materials with exceptional light-manipulating capabilities show significantly enhanced chiroptical response and capability of light manipulation, which have emerged as a promising chiral platform for applications in biosensing, catalysis, and photonics. Scientists now report a novel class of chiral materials called bichiral nanoparticles that can easily tune the sign of circular dichroism through the hybridization of bichiral centers without inverting the geometric chirality.
In an effort to reduce the size of optical spectrometers, researchers have been working on developing miniature on-chip spectrometers that could be integrated into small handheld devices or even smartphones. Now, reducing the size down to the micrometer scale, researchers have developed a single-dot spectrometer based on an in situ modulated perovskite photodetector. The device is enabled by photogain manipulation controlled by ion redistribution in the perovskite film under an externally applied bias. This unique spectrometer design breaks the footprint-resolution restriction of spectrum analysis and leads to a new design direction of perovskite in situ modulation for the development of new functional devices.
Blackbody response is highly desired in two-dimensional (2D) infrared photodetectors, which determines their practical applications. However, limited by the thickness and complex defects of 2D materials, 2D photodetectors still suffer from problems such as low quantum efficiency and large dark current. Researchers now demonstrate fully depleted self-aligned van der Waals (vdW) photodetectors based on a heterosandwiched structure.
One convenient way to manipulate nanoscale objects with remote controllability is actuation and propulsion by light, which is largely based on optical and photothermal-induced forces. Unfortunately, the output of optical and photothermal-induced forces is small and speed is slow. This changes with a novel and intriguing nanoactuation system: plasmonic nanodynamite. This system can be optically triggered to eject gold nanobullets with an initial speed of up to 300 m/s.
Spontaneous charging of interfaces between water and hydrophobic media is a mysterious feature whose nature and origin - despite many efforts to explain them - are still not fully understood. Many spectroscopic results and interpretations along with computational work are not consistent with one another and a consensus on the nature and origin of interfacial charging has not been reached. A clear understanding of this puzzling phenomenon needs a variety of approaches from diverse perspectives, which, hopefully will all add up and be pieced together towards a complete description of the full picture.
Ultra-narrow optical features with a spectral bandwidth below 1 megahertz are highly sought-after for applications in ultrahigh-precision sensing, narrow-band filtering, and information storage for optical computing - but unfortunately they are extremely challenging to generate. But now there is a novel way to achieve ultra-narrow optical features. And unlike conventional approaches, it is cost-effective, has a simple arrangement, and is loss-free, while offering on-demand tunability and ultrahigh sensitivity.