Particles several tens of nanometers in size were aligned in the desired positions in a controlled manner by using capillary force interaction and suspension flow. Latex beads 40-nm in diameter were aligned linearly around a 10-µm-hole template fabricated by lithography. Further control of their position and separation was realized using colloidal gold nanoparticles by controlling the particle-substrate and particle-particle interactions using an optical near field generated on the edge of a Si wedge, in which the separation of the colloidal gold nanoparticles was controlled by the direction of polarization.

The effect of a cavity on the third-order optical nonlinearity, is studied for a two-level system with excitation frequency ω₀, as a function of the Q factor, coupling constant g, and longitudinal (γ₁) and pure transverse (γ₂) damping constants. The largest enhancement is found in the strong-coupling regime with γ₁+2γ₂=ω₀/2Q. Large enhancement is also achieved in the weak-coupling regime satisfying the condition , and the intensity depends on damping constants only. The calculation is based on the cavity QED because the semiclassical treatment of the cavity quasimode leads to incorrect optical nonlinearity.

We make a theoretical study about the laser-induced radiation force exerted on nano materials under a quantum mechanical resonance condition of electronic systems [1] confined in them. In our recent study, we have clarified that the remarkable effects of the electronic resonance appear in the radiation force on the small object whose size is much smaller than the light wavelength; (A) the acceleration on the object gets larger as the size decreases, (B) the peaks with less heat appear in the force spectra even under the resonance condition, (C) the peak position sensitively varies with the nanoscale-size changes. These are useful for the optical manipulation to precisely control the mechanical motions of nano materials. In this paper, toward the experiment to verify the above results, we discuss the dependence of the mechanical motion of nano objects on the width of the incident laser light, and on the diffusion and friction effects assuming that they are floating in the superfluid helium-4 with the cryogenic condition where the electronic resonance effects become conspicuous. The results of calculations show that the particular nano objects, whose resonance energy corresponds to the center frequency of incident laser, can move away from others over macroscopic distance beyond diffusion length. This means that we can observe the distribution of sizes and qualities of nano objects as a macroscopic spatial distribution of them if we prepare appropriate conditions of incident light. We call this new technique 'Nano Optical Chromatography (NOC).'

We approach nanophotonic computing on the basis of optical near-field interactions between quantum dots. A table lookup, or matrix-vector multiplication, architecture is proposed. As fundamental functionality, a data summation mechanism and digital-to-analog conversion are experimentally demonstrated using CuCl quantum dots. Owing to the diffraction-limit-free nature of nanophotonics, these architectures can achieve ultrahigh density integration compared to conventional bulky optical systems, as well as low power dissipation.

In nanophotonic device operations, characteristic features on a nanometer scale, such as locally excited states, dependence on the excitation number, and spatial symmetry of a system, play an important role. Using these features, selective excitation energy transfer via an optical near field is shown for a quantum-dot system with discrete energy levels. This selectivity strongly depends on a dipole-inactive state of an exciton, which cannot be excited by the far-field light. Operation principles of logic gates, photon storage, and quantum information processing device, which are based on the selectivity, are proposed, and the temporal dynamics are investigated analytically and numerically by using quantum theory. Nanophotonic devices, which are constructed from quantum mechanical and classical dissipative systems, are expected to become one of a key technologies in future device architecture.

We investigated the initial stage of Zn dot growth using near-field optical chemical vapor deposition. The dependence of the rate of Zn dot deposition on dot size revealed that the deposition rate was maximal when the dot grew to a size equivalent to the probe apex diameter. Such observed size-dependent resonance was in good agreement with theoretical results for dipole-dipole coupling with a Forster field between the deposited Zn dot and the probe apex.

The radiation properties of oscillating electric dipoles are studied theoretically for three and four layered systems including a single metallic slab based on angular spectrum representation of vector spherical waves. One of the remarkable results obtained is the transmission energy spectrum showing strong dependence on the thickness of a dielectric layer placed between oscillating electric dipole and metallic surface, which explains the experimental results of molecular fluorescence into surface plasmon modes. The theory based on angular spectrum representation and tunneling current provides us with a clear identification of plasmonic excitation transfer, transmission loss associated with plasmon transport in metallic layer, and energy dissipation or quenching of excitation due to surface plasmon excitation at the metallic surface in relation to the characteristic complex wave number of evanescent waves.

We observed the optically forbidden energy transfer between cubic CuCl quantum dots coupled via an optical near-field interaction using time-resolved near-field photoluminescence (PL) spectroscopy. The energy transfer time and exciton lifetime were estimated from the rise and decay times of the PL pump-probe signal, respectively. We found that the exciton lifetime increased as the energy transfer time fell. This result strongly supports the notion that near-field interaction between QD makes the anti-parallel dipole coupling. Namely, a quantum-dots pair coupled by an optical near field has a long exciton lifetime which indicates the anti-parallel coupling of QDs forming a weakly radiative quadrupole state.

We demonstrate a novel fiber device exhibiting magnetic circular dichroism (MCD) and Faraday rotation in sharpened optical fibers coated with Fe. The degree of MCD was 0.68 in a magnetic field of 0.35 T and the Faraday rotation angle was as great as 110 degrees. Such great magneto-optical effect is due to optical near-field interactions in the sub-wavelength region, i.e., in the tip of the near-field fiber probe. These effects can be attributed to the large magnitude of the magneto optical coefficient of Fe.

We have presented a new analytical method for the stub-loaded ridge waveguide that is a candidate of leaky-wave antennas in the millimeter-wave region. This guide has many singular conductor edges, so that its accurate analysis is very difficult. The present method overcomes such difficulty by introducing the singular fields at the edges into the field expressions beforehand. Then we have investigated the dispersion characteristics for various structural parameters, to find a structure suitable to antenna applications. Finally, we have verified their behavioral feature experimentally.

In search of suitable white-LED for general illumination, we fabricated various types of white-LEDs using different methods. As the first method, we used the multichip method in which multiple emitters were mounted in one package. This type showed a good general color-rendering index (Ra) = 90 by the optimizing the emission wavelength of each LED chip. However, the electric driving circuitry was too complex for use in general illumination. Secondly, we used a monolithic white-LED by using the multicolor emitting multiple-quantum well (MQW) for the active layers, which consisted of quantum wells (QWs) with different In compositions. A high Ra = 80.1 was obtained in the three-color-emitting white-LED but the luminous efficacy (η_L) was only 8.11 lm/W. As the third method, we used the color conversion method using phosphors. We fabricated a white-LED which consisted of a near-UV-LED chip and blue/yellow phosphors in order to improve the luminous efficacy of the white-LED under high forward-bias current. At 100 mA, the luminous flux (I_L) was estimated to be 7.6 lm. However, this white-LED degraded quickly, because the epoxy resin used for package was the general purpose one and deteriorated under the UV-light from the n-UV-LED. Next, we improved the Ra and η_L of a traditional white-LED which consisted of blue-LED chip and yellow phosphor. In order to improve the Ra, we added a newly developed red phosphor. We obtained a Ra = 87.7 at low-color-temperature. Then, in order to improve the efficiency of the white-LED, we improved the extraction efficiency (η_EX) of the blue-LED by using a patterned sapphire substrate and a high reflection Rh-mesh-patterned p-electrode. Then, we obtained a 62.0 lm/W at 20 mA. As a result, we concluded that the color conversion method of using a blue-LED for general illumination has advantages in efficiency, color-rendering, cost and lifetime. It also has simpler electric driving circuitry.

This investigation proposed a novel dual-mode circular patch bandpass filter (BPF) with enhanced stopband performance. The novelty of the proposed structure is to use a pair of square etched areas acting as a perturbation element on the circular patch resonator such that two split modes are coupled and the filter structure can be reduced. The coupling coefficients of two split modes are obtained. To improve the stopband performance, a pairs of H-shaped defected ground structure (DGS) cells are used below the input/output port to suppress the spurious response of the proposed BPF. The equivalent circuit of the DGS cell is discussed and the relations between bandstop characteristic and the suitable DGS dimensions are also investigated. The proposed BPF is demonstrated with a central frequency f_o = 2.2 GHz, a 3-dB fractional bandwidth of 8% and a wider stopband of -35 dB from 2.5 to 6 GHz. Measured results of experimental filter have good agreement with the theoretical simulated results.

Fast and simple algorithm of a parity checker for a large residue numbers is presented. A new set of RNS moduli with 2^r-(2^l1) form for fast modular multiplication is proposed. The proposed RNS moduli has a large dynamic range for a large RNS number. The parity of a residue number can be checked by the Chinese remainder theorem (CRT). A CRT-based parity checker is simply organized by the Montgomery reduction method (MRM), implemented by using multipliers and the carry-save adder array. We present a fast parity checker with minimal hardware processed in three clock cycles for 32-bit RNS modulus set.

A single chip analog and class D switching mixed mode audio power amplifier using 0.35 µm CMOS process is presented in this paper. It has on-chip power MOSFET's and adopts a novel reverse recovery current free gate control that can reduce EMI noise and current stress of the power MOSFET's. It shows about 0.1% THD at 1 kHz and up to 87% efficiency at 4 Ω BTL at 3.3 V single power supply.

A side-coupled microstrip open-loop resonator is presented for design of harmonic-suppressed bandpass filters with compact size. In geometry, the open-ended microstrip feed line is put in close proximity to the loop resonator at the opposite side of an opened-gap. In design, its length is properly lengthened to establish the orthogonal even- and odd-symmetrical current distributions along the two coupled strip conductors. It thus results in cancellation the 1st parasitic resonance. The two-stage open-loop filter is first constructed and its performance is studied under varied feed line lengths. Furthermore, a four-stage filter block is optimally designed at 2.52 GHz and its circuit sample is fabricated with the overall length less than 60% of one guided wavelength. The measured insertion loss at the 1st harmonic is higher than 30 dB, the stopband covers the range from 2.8 GHz to 7.0 GHz, and the dominant pass bandwidth is about 9.0%.

An infrared (IR) transcutaneous remote control was designed for use in the totally implantable middle ear system. Considering the IR reflection, absorption and scattering effect of the skin, the required IR radiant intensity is calculated. After we have implemented the designed control, the transcutaneous operation experiment was carried out using a porcine skin.

This paper presents a wide frequency range delay-locked loop implemented with a 0.35 µm CMOS technology, which can overcome the limited frequency range and false lock problem of conventional delay-locked loop (DLL). The proposed simple DLL architecture comprising frequency and phase detector has better process-portability. The implemented DLL covers frequency range from 10 MHz to 200 MHz, which is limited only by the characteristics of delay cell. The DLL consumes 19.8 mW and shows 13 ps rms jitter at 3.3 V, 150 MHz condition.

A TMTR code is specified as (=2,=3,k) constraint. In this work, an approach for constructing (=2,=3,k) codes is presented. Based on this construction, a rate 8/9 code with k=7 is found. This code can achieve better timing recovery performance compared to the proposed previously TMTR code with k=11. An enumerating encoder and decoder exist for constructed (=2,=3,k) codes. A look-up table for the encoder/decoder is not required. Simulation results on an E²PRIV recording channel reveal that the TMTR code provides 2.2 dB gain over an uncoded case.