A spectral intensity distribution of interference colors which is a function of optical path difference (OPD) is represented as a pattern vector on a subspace. A new algorithm to design a color scale on the subspace to estimate OPD values is proposed. In experiments, interference colors generated by a differential interference microscope (DIM) were examined. A subspace spanned by four orthogonal bases was constructed to make a color scale to determine OPD values in the range between 0 nm and 1000 nm. Estimated OPD values almost coincided with these expected. In an experiment on two-dimensional interference colors obtained by a spherical surface of a ballbearing observed by DIM, the resultant OPD distribution coincided well with that expected within a standard deviation of 12.8 nm.

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The single photon emission computed tomography (SPECT) imaging system has shift-variant characteristics due to non-uniform attenuation of gamma-ray, collimator design, scattered photons, etc. In order to provide quantitatively accurate SPECT images, these characteristics should be compensated in the reconstruction. This paper presents a new method to correct the shift-variant characteristics, which is based on a continuous-discrete mapping model and filtered backprojection (FBP) method, in which the projection data are assumed to be acquired by narrow ray sum beams in the FBP method and the assumed data set is expressed as a linear combination of the actual projection data. Narrow ray sum beams are approximated by a weighted sum of the original sensitivity functions. Thus, at the reconstruction the projection data are first modified using an approximation and the FBP method is then applied to the corrected projection data and a SPECT image is reconstructed. We further propose a technique that requires the inversion of smaller matrices than the conventional algebraic method; the amount of calculation and memory space become smaller and the stability of the calculation is greatly improved as well. The results of the numerical simulations are also demonstrated.

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The problem of classification of images that have a perfectly random nature is considered. We propose a new approach to solve this problem that is based on the use of the synthetic discriminant functions being synthesized to separate linearly the power spectra of random image fields to be classified. In the stage of both discriminant function synthesis and classification, the statistical technique of power spectrum estimation is employed. The realization of the proposed approach by means of a hybrid computer-optical technique is discussed, and its effciency is illustrated by two examples of real-world texture classification.

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A compact transmissive waveguide-type dispersion compensation device that uses waveguide grating routers is proposed. This device provides dispersion compensation in long-haul fiber transmission lines and can also be used as a pulse compressor for ultrashort optical pulse generation. A device for the pulse compression of picosecond-length optical pulses has been designed and is numerically analyzed. The proposed device works as a compact (on the centimeter order) and transmissive pulse compressor for picosecond optical pulses.

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The upgrade of the actual large laser facilities (GEKKO XII in our case) implies an increase of filling-factor, but avoiding the generation of spatial high frequencies. To reach that purpose we intend to construct the beams using serrated apertures with an optimised shape. The performances of our system led after simulation to a 70% filling factor with less than 2% fluctuation on the laser pattern intensity map. The optimisation was also checked from a financial point of view. The usual serrated apertures are already giving good results, so we attached ourselves to seek for financial effciency.

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Laser ablation for the atomic emission spectroscopy of a glass sample is studied using pulsed UV laser systems and the effect of the laser wavelength is investigated. The threshold fluence for ablation is decreased and the detection sensitivity is improved for shorter wavelengths. Furthermore, very thin (less than 1 nm/shot) surface slicing is possible at a wavelength as short as 193 nm. Polymers also show good ablation characteristics. Improvement of sensitivity and spatial resolution by using shorter wavelength laser ablation is discussed for Na detection in a glass sample.

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A digital filtering approach to fast simulation for interferometric gravitational wave detectors of Michelson topology involving dynamical coupled cavities was developed in a recent paper. The present paper describes its application to detectors which might be of Sagnac topology with ring-cavities in arms and thus would be characterised by a different and more complicated nature of coupling among fields in various constituent cavities. The simulation results show that digital filtering approach is successful in developing a fast and reasonably accurate algorithm for the computation of dynamical evolution of fields in such a detector.

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A lidar network system consisting of two Mie scattering lidars and one differential absorption lidar was developed to measure the atmospheric environment in Jakarta. The three lidars were installed at three locations in Jakarta to study atmospheric boundary layer structure and transportation of atmospheric pollutants. The Mie scattering lidars employ compact flashlamp pumped Nd:YAG lasers operated at 1064 nm fundamental. They are installed in shelters and directed vertically. One of the Mie lidar has a rotating wedged window for scanning conically to measure wind velocity using a correlation method. The DIAL system employs two Nd:YAG laser-pumped optical parametric oscillators. The DIAL is designed to measure distribution of ozone and SO₂ in the near UV region, and NO₂ in the 450-nm region. The system is installed in a shelter and has a full scanning capability.

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A simple method for determining the absorption coeffcient of oxyhemoglobin and deoxyhemoglobin in human blood is proposed. The method is based on a variation of the complex propagation constant of guided wave in a thin-film optical waveguide. On the waveguide layer, a serial multi-channel sample chamber is constructed to vary the interaction length between the evanescent field and the sample, and the dependence of the sensor response on the interaction length is investigated for various concentrations of two hemoglobins. The response of this sensor is linearly proportional to the interaction length and the concentration of the two hemoglobins. The attenuation constant due to the evanescent field absorption between the channels is experimentally obtained with the designed sensor, and the absorption coeffcient is determined by the proposed method. The determined absorption coeffcients coincided with those obtained by conventional transmission measurement.

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