A5101664747- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Photonic Crystals and Applications
- Optical Coatings and Gratings
- Near-Field Optical Microscopy
- Random lasers and scattering media
- Photonic and Optical Devices
- Force Microscopy Techniques and Applications
- Neural Networks and Reservoir Computing
- Integrated Circuits and Semiconductor Failure Analysis
- Nanofabrication and Lithography Techniques
- Quantum Dots Synthesis And Properties
- Advanced biosensing and bioanalysis techniques
- Terahertz technology and applications
- Orbital Angular Momentum in Optics
- Semiconductor Lasers and Optical Devices
- Molecular Junctions and Nanostructures
- Advanced MEMS and NEMS Technologies
- Quantum optics and atomic interactions
- Metamaterials and Metasurfaces Applications
- Liquid Crystal Research Advancements
- Nanocluster Synthesis and Applications
- Advanced Fluorescence Microscopy Techniques
- Mechanical and Optical Resonators
- Structural Analysis and Optimization
National Cheng Kung University
2007-2020
Beihang University
2018
University of Washington
2016
National Synchrotron Radiation Research Center
2013
University of Illinois Chicago
2013
Northwestern University
1993-2010
ITRI International
2007-2008
National Pingtung University of Science and Technology
2007
Seoul National University
2007
Electro Optical Systems (Germany)
2007
In this work, we use dark-field microscopy to observe a new plasmon resonance effect for single silver nanocube in which the line shape has two distinct peaks when particles are located on glass substrate. The dependence of size and is characterized, it found that bluer peak higher figure merit chemical sensing applications than other particle shapes have been studied previously. Comparison measured results with finite difference time domain (FDTD) electrodynamics calculations enables us...
We have observed spatial confinement of laser light in micrometer-sized random media. The optical is attributed to the disorder-induced scattering and interference. Our experimental data suggest that coherent amplification scattered enhances interference effect helps confinement. Using finite-difference time-domain method, we simulate lasing with feedback active medium.
Extensive 3-D finite-difference time-domain simulations are carried out to elucidate the nature of surface plasmon polaritons (SPPs) and localized (LSPs) generated by nanoscale holes in thin metallic films interacting with light. Both isolated nanoholes square arrays gold considered. For nanoholes, we expand on an earlier discussion Yin et al. [Appl. Phys. Lett. 85, 467-469 (2004)] origins fringe patterns film role nearfield scanning optical microscope probe interactions. The associated...
The generation of surface plasmon polaritons (SPP's) at isolated nanoholes in 100 nm thick Au films is studied using near-field scanning optical microscopy (NSOM). Finite-difference time-domain calculations, some explicitly including a model the NSOM tip, are used to interpret results. We find holes act as point-like sources SPP's and demonstrate that interference between directly transmitted wave allows for determination wavelength, phase, decay length SPP. intensity patterns can be...
The sub-diffraction imaging of the optical near-field in nanostructures, based on a photochemical technique, is reported. A photosensitive azobenzene-dye polymer spin coated onto lithographic structures and subsequently irradiated with laser light. Photoinduced mass transport creates topographic modifications at film surface that are then measured atomic force microscopy (AFM). AFM images correlate rigorous theoretical calculations intensities for range different nanostructures illumination...
In an active random medium, the combination of multiple scattering with light amplification may lead to laser action. However, it is crucial but sometimes difficult distinguish between amplified spontaneous emission and lasing. By varying amount in amplifying we have observed transition from lasing coherent feedback. We found out when occurs through measurement mean free path. Our numerical simulation based on direct solution Maxwell equations clearly illustrates oscillation due increase medium.
We report a new finite-difference time-domain (FDTD) computational model of the lasing dynamics four-level two-electron atomic system. Transitions between energy levels are governed by coupled rate equations and Pauli Exclusion Principle. This approach is an advance relative to earlier FDTD models that did not include pumping dynamics, or Further, method proposed in this paper more versatile than conventional modal expansion electromagnetic field for complex inhomogeneous laser geometries...
We have achieved lasing in InAs quantum dot embedded GaAs microdisks under optical pumping. Above the threshold, a drastic increase of emission intensity is accompanied by decrease spectral linewidth whispering gallery modes. The laser light linearly polarized. polarization direction parallel to disk plane. wide gain spectrum dots allows simultaneous several modes microdisk.
Gapped rods provide a unique platform for elucidating structure/function relationships, both single-molecule electrochemical techniques and surface-enhanced Raman scattering (SERS). This paper attempts to elucidate the dependence of SERS intensities on gap topography distance gold gapped with segment lengths varying over wide range (40−2000 nm). Significantly, we have determined that rough gaps lead smaller enhancement than smooth these structures even though larger total surface area. Both...
Plasmon hybridization modes are observed in the extinction spectra of a metal–insulator–metal (MIM) nanodisk array fabricated using nanospherical-lens lithography. Two distinct this vertically aligned configuration. Theoretical simulation indicates that bonding mode located at lower energy level exhibits an antiphase charge distribution and corresponds to dark plasmon mode. This is vastly different compared antibonding conventional dimer The tunable over wide spectral range simply by varying...
A micropositioning stage with large travel range has been designed and built. The combines a piezoelectric driving element, flexure pivoted multiple Scott–Russell linkage, parallel guiding spring. Quality engineering techniques are used to optimize the configuration of device in order achieve maximum displacement gain minimum angular deviation. simple open-loop compensator is applied reduce hysteresis dynamic response stage. experiment shows that achieved vacuum-compatible greater than 100...
A flexible and parallel procedure to generate large-area, free-standing films of subwavelength hole arrays has been demonstrated. This method is materials-general, multilayered different materials were constructed. The optical quality these was tested using a near-field scanning microscope, which revealed the formation surface plasmon standing wave patterns that consistent with numerical simulations. Because properties holes film can be easily tailored, new types plasmonic photonic devices...
In coherent homodyne apertureless scanning near-field optical microscopy (ASNOM) the background field cannot be fully suppressed because of interference between different collected fields, making images difficult to interpret. We show that implementing heterodyne version ASNOM allows one overcome this issue. present a comparison and through analysis gold nanowells, integrated waveguides, single evanescent wave generated by total internal reflection. The approach for control interferometric...
Nanoaperture arrays in a silver film were quantitatively evaluated, for the first time, to determine absolute Raman scattering enhancement factors as function of aperture lattice spacing using nonresonant analyte. The arrays, with 200 nm diameter apertures and varying 50 thick film, resulted an average area-corrected SERS factor (6 ± 3) × 107 514.5 excitation. Comparison between theory experiment provided critical insight into magnitude origin these nanoaperture spacing. measured was...
We present an analytical approach to random lasing in a one-dimensional medium, consistent with transfer matrix numerical simulations. It is demonstrated that the threshold defined by transmission through passive medium and thus depends exponentially on size of system. Lasing most efficient regime strong three-dimensional localization light discussed. argue should have anomalously fluctuations from probe probe, agreement recent measurements.
This study elucidates for the first time an all-optically controllable random laser in a dye-doped polymer-dispersed liquid crystal (DDPDLC) with nano-sized LC droplets. Experimental results demonstrate that lasing intensity of can be controlled to decrease by increasing irradiation time/intensity one green beam, and increase red beam. The all-optical controllability is attributed (red)-beaminduced isothermal nematic-->isotropic (isotropic-->nematic) phase transition droplets trans-->cis...
A piezoelectric-driven Scott–Russel linear micropositioner utilizing the stick-slip effect of friction to drive a slider is presented. Effects sawtooth, impulse, and transcendental electrical wave forms on device performance are studied via numerical simulation experiment test. The demonstrates that positioning step sizes 0.05–120 μm can be achieved at low input voltages 2–25 V essentially with unlimited travel range.
This work investigates a novel color cone lasing emission (CCLE) based on one-dimensional photonic crystal-like dye-doped cholesteric liquid crystal (DDCLC) film with single pitch. The wavelength in the CCLE is distributed continuously at 676.7-595.6 nm, as measured increasing oblique angle relative to helical axis of 0-50 degrees . demonstrates that coincides exactly long edge CLC reflection band angles Simulation results dispersion relations different using Berreman's 4X4 matrix method...
The effect of surface plasmon resonance (SPR) on the blinking emission photoluminescence from noble metal nanostructures still requires further investigation in quantum mechanics and limits their applications. We investigate one photon luminescent intermittency with differently sized sea-urchin-shaped nanoparticles, known as nano-sea-urchins (NSUs). probability "on" process NSUs increases due to strong electric field SPR. This mechanism is explained by reaction potential threshold model we...
Rapid detection of the handiness chiral molecules is an important topic for pharmaceutical industries because drugs with opposing sometimes exhibit unwanted side effects. In this research, a rapid optical method proposed to determine drug "Thalidomide". The platform large array three-dimensional (3D) twisted metamaterials fabricated novel by combining nanospherical-lens lithography (NLL) and hole–mask (HML). fabrication high-throughput cover area. Strong circular dichroism (CD) response...
We study light transport in ordered, partially and completely random one-dimensional (1-D) systems. In a periodic structure, there are three types of passbands with different origins. When disorder is introduced to system, the change differently, depending on their The transmissivity decay length near band edges decrease drastically. stopbands widened. introduction randomness structure enhances localization frequency regions which it delocalized structure. resonant cavity formed by two...