Cylindrical-wave controlling, generating and guiding devices

An apparatus for controlling guided cylindrical waves comprising a disk-like waveguide, in which a guided cylindrical wave at a wavelength can propagate, said waveguide consisting of at least one disk-like wave-transmitting thin film, whose thickness varies such that a plurality of concentric-circle ridges and grooves is formed on one surface of said thin film, whereby said ridges and grooves have a plurality of circular interfaces, said ridges and grooves and said interfaces are around a center axis,

• said guided cylindrical wave propagating in said waveguide, due to the thickness variation in said thin film, having different radial wavevectors on two sides of each of said interfaces,
• said guided cylindrical wave being partially reflected by said interfaces, being partially transmitted across said interfaces and being partially diffracted away from said thin film by said interfaces due to the radial wavevector differences
• the intensities and phases of the reflected waves, the transmitted waves and the diffracted waves due to said interfaces being controlled by a sequence of phase changes, .DELTA..sub..PSI. n=1, 2, . . . , M, where M is a total number of said interfaces.
• said phase changes being calculated by the following equation, ##EQU14## where q.sub.n,11, q.sub.n,12, q.sub.n,21, and q.sub.n,22 are complex quantities and are calculated by the following matrix equation and initial condition ##EQU15## where m is an integer,
• H.sub.m.sup.(1) and H.sub.m.sup.(2) are mth order Hankel functions of the first and second kind respectively.
• r.sub.n is a radius of an nth circular interface of said circular interfaces from said center axis, and
• u.sub.n and u.sub.n+1 are the radial wavevectors of said guided cylindrical wave immediately inside said nth circular interface and immediate outside said nth circular interface respectively.