Dispersion theory of linear and nonlinear susceptibilities are considered with the aid of complex analysis.

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A miniaturized 1.55 μm tunable fiber Bragg grating (FGB) filter is proposed and successfully demonstrated using an aluminum ceramic-tube with a tungsten thick film sleeve microheater. Fine tuning of the Bragg reflective wavelength with 0.0135 nm/°C is achieved by adding the constant thermal distribution along the uniform FBG with a 0.3 nm bandwidth. Furthermore, a 1.5 nm linearly chirped reflection bandwidth is obtained by thermal gradient loading.

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It is essential to know the wavelength dispersion of a planar microlens in order to suitably design optical systems which use such a component. For this purpose, the measurement of focal length over a wide range of the spectrum has been performed. It was clarified that the focal length varies by about 20% from blue (λ=0.442 μm) to near-infra red (λ=1.55 μm) region. The maximum index difference between the lens center and substrate, an important parameter for the characterization of planar microlenses, has been estimated as a function of wavelength using the ray equation. The effect of angled incidence has been discussed.

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A newly designed cylindrical optical micro-rotator which has slopes for trapping and rotation on its upper surface is proposed. The cylindrical shape is effective in decreasing viscous drag force (damping factor) in the medium. A ray-tracing method considering the beam waist is employed to analyze the radiation pressure exerted on the upper surface of the rotator. We have demonstrated optical trapping and high speed rotation for various optical beam parameters such as the lens numerical aperture and the Gaussian mode profile as well as rotator shape parameters including oblique angle, height and diameter.

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Optical characteristics of the retroreflector in space (RIS) on the Advanced Earth Observing Satellite (ADEOS) in orbit were tested using a second harmonics Nd:YAG laser. The intensity of reflection from the RIS was analyzed with an intensified charge coupled device camera by comparing the image with those of stars. It was confirmed that the RIS in orbit is working properly as a retroreflector.

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Quadrature squeezed light generation with optical pulses in a fiber loop mirror is analyzed through computer simulation. The effect of guided acoustic wave Brillouin scattering (GAWBS) in optical fibers as well as those of nonlinearities and chromatic dispersions are considered for the first time. The relation between the GAWBS noise and the optical pulse width is discussed in detail. It is found that the nearly fundamental soliton pulse is optimum to get the largest squeezing even if the GAWBS noise is effective. The broadened pulses suffer larger degradation of squeezing due to this noise.

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The large real-time hologram device made by the previous Bi₁₂SiO₂₀ single crystal wafer cutting method poses several problems such as a large residue of material hinders the practical use. A study was carried out to fabricate a real-time hologram device using inexpensive laterally cut circular (1 0 0) Bi₁₂SiO₂₀ single crystal wafers which would be suitable for practical use for 3-dimensional display. An angle incident on a (1 0 0) wafer is applicable to the real-time hologram. An optimal electrode design for a device with uniform diffraction efficiency was considered, and the device properties were experimentally investigated.

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A model of an optical neural network with learning ability is proposed. We numerically evaluate the learning ability of the proposed network by using parameters determined by experiments. Adaptive connections between artificial neurons are implemented using photorefractive (PR) waveguides that can be optically modified by guided beams. The network consists of three layers and has bipolar weights within the limited range. The bipolar weight is encoded as the difference between optical power transmittances of signal beams in two channels of the PR waveguides. The adaptivity of the transmittance of PR waveguide is experimentally evaluated and is incorporated into the proposed network simulated in a computer. The proposed network is trained by a simplified local learning algorithm. Numerical results showed that the proposed three-layered network with six hidden neurons can solve the exclusive-or problem.

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Volume data is interpolated using pseudo color and an electro-optical-hybrid-system. The method proposed in this paper is called optical interpolation. The visualization of a volumetric array of computed tomography data is achieved using the optical interpolation technique in combination with the optical model and the electro-optical-hybrid-system. To show the advantages of optical interpolation, the results are compared with those obtained by the traditional technique.

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Dependence of Stokes dynamics in stimulated Brillouin scattering generated in optical fibers on the pump power, the nonlinear refractive index, the fiber length, and the feedback powers of the pump and the Stokes is numerically analyzed. The Stokes power fluctuation becomes complicated and chaotic as the nonlinear refractive index and the input pump power increase in a fiber of sufficient length. The Stokes dynamics is less complicated and the chaotic region decreases in a pump power-reflectivity domain in a short fiber. The chaotic behavior appears without regular tendency in relation to the feedback power. Taking into account the pump feedback, the chaotic region expands and some Stokes behaviors are different in the P_p-R domain graph, compared with the case with the Stokes feedback alone, although this feedback does play an essential role in Stokes dynamics.

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An innovative photoacoustic source for ultrasonic non destructive evaluation (NDE) and clinical diagnosis is proposed. The working principle is based on thermal conversion of laser pulses into a metallic film evaporated directly onto the tip of an optical fiber. Attractive advantages of the proposed transducer are high frequency, large bandwidth and good efficiency.

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This work presents a new technique for the measurement of second-order optical nonlinear coefficients from the absolute radiant power of the parametric fluorescence emission. It is based on calibrated detectors regarded as secondary radiometric standards. This technique makes it possible to skip a number of problems usually encountered with standard techniques based on calibrated neutral density filters and reference sources of light at much higher power levels. We infer a value for the d₃₁ nonlinear coefficient of LiIO₃ from spectral measurements of the fluorescence power integrated over all solid angles, by defining the wavelength bandwidths with interference filters. Moreover, by performing the measurements on the ultraviolet and visible emission lines of an argon ion laser in the range from 351 to 488 nm, the wavelength dependence of d₃₁ is compared with the expected one obtained by Miller's dispersion law.

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Phase conjugate matched filtering was performed with optical phase conjugation in Fourier-transforming backward degenerate four-wave mixing. A methyl-orange-doped polyvinyl alcohol (MO/PVA) film was used as a phase conjugator. The influence of the film thickness upon decay of a correlation signal due to phase mismatching was investigated. The thickness was varied from 15 μm to 90 μm. Reduction of the film thickness relaxes the tolerance for phase mismatching, which also occurs when a large reference picture is placed in a pump beam or when a reference picture shifts from the optical axis of the pump beam. Using a MO/PVA film of 15 μm thickness, we obtained allowable angles of 3.4for a horizontally expanded reference picture and larger than 4.3for a vertically expanded reference picture, assuming about 40% reduction of a correlation signal is allowable.

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A multi-spectral polarimeter (FPR1000) is designed to measure the radiance and degree of polarization of the sky radiation as well as the extinction of solar irradiance using the same optical system. This enables us to make consistent measurements of the direct solar and diffused sky radiation. Measurements are made at the same wavelength regions as Polarization and Directionality of the Earth's Reflectances (POLDER) and Ocean Color and Temperature Scanner (OCTS) onboard Advanced Earth Observing Satellite (ADEOS). Based on measurements for the Langley plot calibration made at Mauna Loa Observatory, the calibration constants are obtained by considering the effect of absorption by water vapor and uniformly mixed gas. Preliminary analyses of the measurements of sky radiation and direct solar irradiance carried out in the western part of the Pacific Ocean are presented. Combined measurements of the extinction of solar irradiance, and the radiance and degree of polarization of sky radiation could be useful in improving retrieval of optical characteristics of aerosol and for atmospheric correction.

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A focusing optical system for a semiconductor laser-diode-array is described. The high-power array consists of a number of minuscule light sources (quantum wells) as well as a stratified structure, so that it requires several design techniques to focus as a pumping source for a laser-diode-pumped solid state laser. Some design techniques for such a focusing system are proposed with examples of the design of an anamorphic optical system.

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We demonstrate a novel low coherence Michelson interferometer which can provide simultaneous measurement of the refractive index and thickness of transparent plates used as a measured object. Unlike the existing low coherence interferometers reported so far, either an object or a focusing lens aligned on the signal arm is scanned repeatedly by a precise translation stage in synchronization with movement of a reflection mirror on the reference arm. The so-called object or lens scanning method gives us two measured quantities a movement distance of the stage between two light focusing states on the front and rear planes of an object and the corresponding optical path difference. These two measured quantities, result in desirable values of the index and thickness of the object with a short calculation. The measurement accuracy of .1% is expected for a thickness of more than 1 mm. In the experiment using the object scanning method, the accuracy of 0.3% or less was successfully attained for nearly 1-mm thick plates of fused quartz, sapphire, LiTaO₃ and slide glass.

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A new fabrication method for polymer micro-optical elements is described which uses the contracting effect of photopolymers during the process of polymerization. Convex and concave microlens arrays and phase gratings were formed by irradiating a ultraviolet (UV)-curable monomer with incoherent UV light through an appropriate metallic mask. The morphological and optical characterization of the fabricated elements reveals that the surface profile of the elements depends on the pattern and aperture size of the mask employed.

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The peak position for a lidar return signal is calculated and measured for the horizontal path with variation of the laser beam divergence angle (θ), and the inclination angle (δ) between the telescope and laser axes. This work shows that θ and δ are very important parameters to use in the design or alignment of a lidar system receiving a good lidar signal. This paper describes an experimental determination of geometrical form factors in the lidar equation. We receive the signals and determine the geometrical form factors by slope method in a homogeneous atmosphere. The differential absorption lidar equation is evaluated for the dual-pulse lidar system. A method using a geometrical form factor determined by the experiment is introduced to correct the error in C₂H₄ measurement. This method shows good correction of measurement error in lidar dual-pulse operation, especially in the short range.

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