Advanced Photonics Research最新文献

2D Layered Superconductors

In article number 2400045, Kaveh Delfanazari showcases methods for the realization of ultrafast terahertz (THz) metamaterial photonic switches on a few nanometer-thick layered high-temperature superconductor van der Waals (vdWs). The metamaterial array offers active modulation of THz amplitude and phase with an ultrafast-picosecond-switching timescale. The device holds promise for the development of future THz communication circuits and systems operating at cryogenic temperatures.

Core–Shell Particles

Essential features of functional optical materials are their interaction with light and underlying structures. In article number 2400091, Markus Gallei and co-workers report the combination of structural colors with cellulose, a renewable and biodegradable biopolymer. The latter acts as reinforcement agents, maintaining the polymer opal film’s structural color and mechanochromic material behavior.

Polymer-Network Liquid Crystals

In article number 2300340, Dan Luo, Kun-Lin Yang, and co-workers show that after partially completed photopolymerization, the polymer network liquid crystal undergoes a secondary polymerization to form an isotropic polymer network when it is heated beyond its clearing point, resulting in an irreversible optical appearance change from transparent to cloudy. It enables applications such as a heating stopwatch and oxygen sensing.

Coherent Perovskites Emitters

In article number 2400033, Kwangdong Roh and co-workers provide a comprehensive overview of the historical progress in perovskite lasers and light-emitting didoes, along with important design considerations essential for their development.

Carbon dots (CDs) show great application potential with their unique and excellent performances. Coal and its derivatives are rich in aromatic ring structure, which is suitable for preparing CDs in microstructure. Coal-burning dust from coal-fired power plants can be utilized as a rich resource to separate and extract CDs. It is shown in the results that there are two main possible mechanisms for the formation of CDs in coal-burning dust. One is the self-assembly of polycyclic aromatic hydrocarbons contained in coal or produced by incomplete combustion of coal. The other mechanism is that the bridge bonds linking different aromatic structures in coal break, which will form CDs with different functional groups when the coals burn at high temperature. Under violet light excitation at 310–340 nm or red light at 610–640 nm, CDs extracted from coal-burning dust can emit purple fluorescence around 410 nm. The mechanism of up-conversion fluorescence emission of CDs is due to a two-photon absorption process. The recycling of CDs from coal-burning dust from coal-fired power plants are not only good to protect environment but will also be helpful for mass production of CDs.

Topological Photonic Insulators

In article number 2400023, Vien Van and Hanfa Song present the design and realization of (2 + 1)D topological photonic insulators hosting all flat bands, which exhibit novel properties such as anomalous Floquet insulator phase, ultra-wide edge mode continuum, super robustness to disorder, and photon caging in compact localized bulk states. These lattices have broadband applications in topologically-protected quantum photonics and programmable photonic circuits.

Photoinduced Structural Modification

In article number 2300326, Ashim Dhakal and co-workers show that photo-induced metastable modification of electronic structure in graphite allows for multiphoton processes that can up-convert an O-band infrared excitation to visible-NIR band in graphite powder. Theoretically, this process can upconvert an infrared light near the wavelength of 3 μm to VIS-NIR wavelengths. It opens exciting new avenues for applications in visible light generation and low-noise imaging using infrared light excitation.

The hole accelerator is proven to benefit the hole injection for traditional light-emitting diodes (LEDs) because the induced electric field provides the holes with more kinetic energy to pass through the electron-blocking layer, enhancing the hole injection efficiency. Herein, the effect of the hole accelerator (HA) layer on the micro-LEDs by modeling the characteristics of the devices with a current density of lower than 10 A cm⁻² is investigated. The simulation results show that the appended HA layer brings a knot of the electric field in the HA layer, leading to higher internal quantum efficiency (IQE) than the device without HA under the low current density. The thickness and composition of HA, the quantum number, and the material of quantum barrier are also simulated and analyzed. The simulated radiative, Shockley–Read–Hall, and Auger recombination rates show that the IQE of the micro-LED with the HA layer is higher than that without the HA layer under the current density of lower than 10 A cm⁻².

Microfluidic lab-on-a-chip (LOC) devices have become essential tools for multitudes of applications in various research fields. 3D printing of microfluidic LOC devices offers many advantages over more traditional manufacturing processes, including rapid prototyping and single-step fabrication of complex 3D structures. In this work, 3D-printed microfluidic devices are designed and fabricated for optical chromatography and sorting. Optical chromatography is performed by inserting a single-mode optical fiber into the device creating a counter-propagating laser beam to the fluid flow. Particles are separated depending on refractive index and size. To demonstrate optical sorting, a cross-type sorter 3D-printed microfluidic device is fabricated that directs the laser beam perpendicular to the flow direction. Design features such as a sloping channel and a channel configuration for 3D hydrodynamic focusing (to aid in controlled sample flow and particle position) help to optimize sorting performance. Stable optofluidic trapping and sorting are successfully achieved using the fabricated microfluidic devices. These results highlight the tremendous potential of 3D printing of microfluidic LOC devices for applications aimed at the optofluidic manipulation of micron-sized particles.