Session Index

A chiral plasmonic metasurface as the circular dichroism metamirror was demonstrated to achieve spectrally selective chirality in the visible wavelengths. The absorption and circular dichroism can respectively achieve 1.7 % and 47.9 % at 640 nm.

 

Double-layered vanadium dioxide and gold thin films were demonstrated to achieve tunable emissivity at low temperature (< 100 °C) in the infrared wavelengths (IR). The emissivity can change from ~15% to ~65% between 4 um ~ 14 um.

 

Here we demonstrated a GaN based achromatic metalens array to provides a new avenue for the structure light application such as distance sensing and 3D environmental construction.

 

We explored the strain-engineered effects on the near-band-edge (NBE) luminescence properties of a bent ZnO microrod at room temparature. A proposed recombination model in a gradient bandgap structure can well describe the luminescence behaviors of our observations.

 

We propose a new SERS substrate produced by electrostatic-field-tunable ferroelectric template with the diluted proton-exchanged region. The triangle-shaped silver nanoparticles with strong SERS activity are formed on the ferroelectric template for the first time. In comparison with conventional samples, the proposed SERS substrate owns 8.63 times the Raman signal enhancement.

 

Typically, the responsivity of photodetector is restricted by the cutoff wavelength which is related to the bandgap or the activation energy of the material in device. In this research, we detect the 4.16 µm Mid-wavelength infrared with Cu/p-type photodetector and measure a high responsivity in 5s open/close chopping.

 

We theoretically study the optical trapping of a gold dimer array upon a free polystyrene nanoparticle (NP) as irradiated by a linearly polarized Gaussian beam. Using MMP method, the 3D streamline of optical force is analyzed to show that the NP can be trapped through the optical vortex.

 

Self-powered photodetectors was realized by spin-coating reduced graphene oxide (rGO) onto an ITO coated flexible PET substrate. The device could work without power because of the work function difference between ITO and Ag. The proposed method reduces the fabrication cost and can be applied to various flexible rGO based devices.

 

We developed a curvature-tunable random laser, for the first time, is implemented for in vivo biological imaging with much lower speckle noise when compared to the non-lasing situation through a simple mechanical bending, which is of great potential for studying the fast-moving.

 

Using the metal-semiconductor diode as IR photodetector, and through the material, device structural and operation bias selection, high response and fast switching can be achieved. The response can reach 1.294 mA/W.

 

The orbital and spin rotations of a single gold nanoparticle or two optically bound nanoparticles induced by a circularly polarized Gaussian beam are studied theoretically. The numerical results show that a stable-equilibrium orbital rotation exits at off-focal plane for both cases and these NPs spin simultaneously.

 

Spectral characteristics of multichannel silver nanoslit array under various environmental refractive index liquids were measured using a smartphone camera based on a LED white light source and a curved grating as an imaging spectrometer. The measured spectra were compared with those detected by a commercial compact spectrometer.

 

A novel process of ammonium hydroxide thermal treatment is proposed to improve the contact resistance of Ti/Al/Ti/Au electerode on plasma-etched n-AlGaN cladding in deep UV LEDs. Experimental results have confirmed that both the operation voltage and external quantum efficiency of the 280 nm LED can be significantly enhanced.

 

We proposed a modularized device utilizing ultraviolet light-emitting diodes (UV-LEDs) as the source of photo-catalyst for water treatment. This equipment consists of two coaxial cylindrical pipes in which UV emitted radially from internal cylinder can reach the TiO2 nano-coating on outer cylinder to trigger photo-catalyst effect to remove organic contaminant.

 

In this study, the electromagnetic coupling of a symmetric Au dimer and an asymmetric Au dimer was investigated by using a finite-difference time-domain method (Fullwave, RSoft).The simulation results show that the asymmetric structure enhanced near-field coupling can be used to manipulate the light-materials at nanoscales.

 

We numerically and experimentally investigate metamaterial absorbers constructed by the metal stress-driven self-folding SRRs. Via radical symmetric design, the uniaxial-isotropic characteristics are demonstrated. Moreover, we perform hybrid scales radical symmetric structures to show multiband absorption properties. The results reveal a high potential to develop multi-functional metamaterial absorber in IR region.

 

The contribution of high work function metal oxide, molybdenum oxide (MoOx) to n-Si photodetectors will be investigated. We will explore their ability for photo-carrier collection on silicon photodetectors. We will change the thickness of MoOx. We will also compare different effects with different contact materials to optimize such photodetectors.

 

We proposed a planar metal-semiconductor-metal (MSM) device for hot-electron excitation. Surface plasmon resonance can enhance the photoemmission of hot electron and also inject the hot electron to the wide band gap materials (Zinc oxide, ZnO). Hot electrons could be collected by the bottom metal which provides the photocurrent enhancement.

 

With the rapid development of optoelectronics, controlling the interaction between light and matters is in urgent demand. In this work, we use stress-driven self-folding method to fabricate vertical metamaterial. By tailoring the geometry of patterns, we can control the light-matter interaction from bianisotropy to inversion symmetry and vice versa.

 

The two approximately same size microspheres from undoped and 10 mM Rhodamine B dye doped ZnO (dye-ZnO) sample were chosen to study their optical emission properties through whispering gallery modes (WGMs). Moreover, the significant enhancement in the intensity of the spectra collected through the doped microsphere was observed.

 

Two arrays of gold nanoparticle placed in different dielectric medium is simulated to understand the plasmon enhanced phenomena. A strong electric field is confined at the metal dielectric interface as well as inter-particle gap up to the order of 106 at excitation wavelength of 542 nm.

 

In this paper, the sapphire-based nano-patterns were fabricated on the deep ultraviolet light-emitting diodes device on a sapphire substrate with and without pattern sapphire substrate by a nano-imprint lithography process. It was used to improve the Light-Extraction Efficiency of the device.