SPATIAL FREQUENCY FILTER AND TIME-FREQUENCY CONVERSION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a completely new input light complete use type spatial frequency filter which has no light quantity loss and a new time-frequency conversion method which uses it. SOLUTION: A phase type diffraction grating group (3a) is constituted by arranging phase type diffraction gratings (3a1 ), (3a2 )...(3an ) having mutually different cycles along a space axis Y orthogonal to an arbitrary space axis X of a linear space signal A on a Fourier plane (101) of a linear Fourier transformation optical system for each of space positions X1 , X2 ...Xn of respective space frequencies of the linear space signal A.