Surface Plasmon Resonance Alcohol Sensor with Ni(OH)2 /Au Structure

Active metasurfaces add a new dimension to static metasurfaces by introducing tunability, and this has received enormous attention from industry. Although various mechanisms have been proposed over the past few years in literature, solutions with good practicality are limited. Liquid crystal (LC)-based active metasurface is one of the most promising approaches due to the well-established LC industry. In this paper, an electrically tunable active metasurface was proposed and experimentally demonstrated using photoaligned nematic LC. The good quality of the LC photoalignment on the metasurface was demonstrated. Tunable transmission was obtained for telecommunication C band and the modulation depth in transmission amplitude of 94% was realized for 1530 nm. Sub-millisecond response time was achieved at operating a temperature of 60°C. The progress made here presents the potential of LC-based active metasurfaces for fast-switching photonic devices at optical communication wavelengths. More importantly, this work lays the foundations for the next-generation liquid crystal on silicon (LCoS) devices that are integrated with metasurfaces (meta-LCoS).

Electrically tuned active metasurface towards metasurface-integrated liquid crystal on silicon (meta-LCoS) devices.

Heavy metals ions as metallic pollutants are a growing global issue due to their adverse effects on the aquatic ecosystem, and human health. Unfortunately, conventional detection methods such as atomic absorption spectrometry exhibit a relatively low limit of detection and hold numerous disadvantages, and therefore, the development of an efficient method for in-situ and real-time detection of heavy metal residues is of great importance. The aptamer-based sensors offer distinct advantages over antibodies and emerged as a robust sensing platform against various heavy metals due to their high sensitivity, ease of production, simple operations, excellent specificity, better stability, low immunogenicity, and cost-effectiveness. The nucleic acid aptamers in conjugation with nanomaterials can bind to the metal ions with good specificity/selectivity and can be used for on-site monitoring of metal ion residues. This review aimed to provide background information about nanomaterials-based aptasensor, recent advancements in aptamer conjunction on nanomaterials surface, the role of nanomaterials in improving signal transduction, recent progress of nanomaterials-based aptasening procedures (from 2010 to 2022), and future perspectives toward the practical applications of nanomaterials-based aptasensors against hazardous metal ions for food safety and environmental monitoring.

Heavy Metal Ions Detection Using Nanomaterials-Based Aptasensors.

DNA-Nanosensors for Environmental Monitoring of Heavy Metal Ions

Green-emitting functionalized silicon nanoparticles as an "off-on" fluorescence bio-probe for the sensitive and selective detection of mercury (II) and 3-mercaptopropionic acid.

Highly sensitive fluorescence-based mercury(II) DNA sensor enhanced by silver(I) activation

Liquid crystal on silicon (LCoS) has been the dominant choice for wavelength selective switches (WSSs) in telecommunication industry due to its high spatial resolution and compatibility with software defined flexible grid feature. Current LCoS devices generally have a limited steering angle, which also limits the minimum footprint of the WSS system. The steering angle of LCoS devices is fundamentally determined by the pixel pitch, which is highly challenging to be optimized without resorting to other techniques. In this paper, we present an approach to increase the steering angle of LCoS devices through the integration with dielectric metasurfaces. Here a dielectric Huygens-type metasurface is integrated with an LCoS device to increase its steering angle by 10°. This approach can effectively minimize the overall size of the WSS system while maintaining a small form factor of the LCoS device.

Increasing steering angle of LCoS in a WSS system through integration with a metasurface.

A dielectric Huygens metasurface was designed as a phase gradient and integrated with a phase-only LCoS device, to increase its maximum diffraction angle limited by the pixel size.

Increasing Diffraction Angle of LCoS Device through Integration with Metasurface

This feature issue is a continuation of a tradition to follow the conclusion of the Optica Topical Meeting on Digital Holography and 3D Imaging (DH+3D). It addresses current research topics in digital holography and 3D imaging that are also in line with the topics of Applied Optics and Journal of the Optical Society of America A.

Daping Chu

Papers

Highly sensitive fluorescence-based mercury(II) DNA sensor enhanced by silver(I) activation

Electrically tuned active metasurface towards metasurface-integrated liquid crystal on silicon (meta-LCoS) devices.

Increasing steering angle of LCoS in a WSS system through integration with a metasurface.

Increasing Diffraction Angle of LCoS Device through Integration with Metasurface

Digital Holography and 3D Imaging: introduction to the joint feature issue in Applied Optics and Journal of the Optical Society of America A.