▽TOP▽活動実績▽２００１年▽

(4)　Random optical fields with long spatial correlations Technical Digest of the Fourth Japan-Finland Joint
　　　　　Symposium on Optics in Engineering　(Osaka, Japan, 2001),pp.13-14,2001-10

　In some applications of laser light scattering to optical measurements, spatial correlation properties of scattered fields play important roles. It is therefore desirable that one can control spatial correlations of the scattered fields. From such a viewpoint, two interesting schemes of generating extremely long spatial correlations are discussed. The first scheme is to illuminate an ordinary planar diffuser by coherent light with a negative power-law intensity distribution, and produces speckle patterns having power-law correlation tails. The second one is to use an annular intensity distribution for the illumination, which can be formed simply by an annular slit or by an illumination optics with an axicon lens. Scattered fields by this type of illumination have extremely long axial correlations and, hence, may be called non-diffracting speckles. Recent studies on these two types of highly correlated scattering patterns are presented.