A diffractive optical element, such as a holographic plasma lens, can be made by direction two laser beams so that they overlap in a nonlinear material, to form an interference pattern in the nonlinear material. The interference pattern can modify the index of refraction in the nonlinear material to produce the diffractive optical element. The interference pattern can modify the distribution of plasma for the nonlinear material, which can adjust the index of refraction. A third laser beam can be directed through the diffractive optical element to modify the third laser beam, such as to focus, defocus, or collimate the third laser beam.

A method for irradiating a medium includes irradiating the medium with an electromagnetic wave which is scattered in the medium and modulated in frequency at a position in the medium; obtaining information corresponding to an interference pattern generated by interference between the modulated electromagnetic wave and a reference wave; and generating a phase conjugate wave, based on the obtained information, which irradiates the medium.

An integrated optical circuit for holographic information processing is disclosed. The optical circuit comprises a photorefractive medium and two transmitter arrays. The transmitter arrays are adapted for locally changing the refractive index of the photorefractive medium for holographic encoding of the information in a working plane of the photorefractive medium by transmitting light via optical paths into the photorefractive medium such that an interference pattern is generated in the working plane. The optical paths and the working plane are arranged in a single optical plane.

An integrated optical circuit for holographic information processing is disclosed. The optical circuit comprises a photorefractive medium and two transmitter arrays. The transmitter arrays are adapted for locally changing the refractive index of the photorefractive medium for holographic encoding of the information in a working plane of the photorefractive medium by transmitting light via optical paths into the photorefractive medium such that an interference pattern is generated in the working plane. The optical paths and the working plane are arranged in a single optical plane.

A diffractive optical element, such as a holographic plasma lens, can be made by direction two laser beams so that they overlap in a nonlinear material, to form an interference pattern in the nonlinear material. The interference pattern can modify the index of refraction in the nonlinear material to produce the diffractive optical element. The interference pattern can modify the distribution of plasma for the nonlinear material, which can adjust the index of refraction. A third laser beam can be directed through the diffractive optical element to modify the third laser beam, such as to focus, defocus, or collimate the third laser beam.