Spatial filter system as an optical relay line

Claim 1

An apparatus acting as an optical relay which translates substantially all rays in a laser beam from an initial position where the power density is low through a plurality of high power amplification stages to a downstream position where the effective optical path length from said initial position is substantially zero and the power density is high with minimal diffraction effects, phase distortion and beam intensity fluctuations, said apparatus comprising at least one spatial filter assembly positioned at a selected spaced relation between said amplification stages; said spatial filter assembly consisting of a pair of lenses separated by a distance equal to the sum of their focal lengths and positioned in selected spaced relationship with respect to said amplification stages to define an optical relay, and means defining a pinhole positioned substantially at a common focal plane of said two lenses.

Claim 2

An apparatus acting as an optical relay which translates substantially all rays in a laser beam from an initial position where the power density is low through a plurality of high power amplification stages to a downstream position where the effective optical path length from said initial position is substantially zero and the power density is high with minimal diffraction effects, phase distortion and beam intensity fluctuations, said apparatus comprising at least one spatial filter assembly positioned at a selected spaced relation between said amplification stages; said spatial filter assembly consisting of a pair of lenses separated by a distance equal to the sum of their focal lengths and positioned in selected spaced relationship with respect to said amplification stages to define an optical relay, and means defining a pinhole positioned substantially at a common focal plane of said two lenses.

Claim 5

An apparatus for optically relaying a laser beam from an initial position where the power density is low through a plurality of high power amplification stages to a downstream position where the effective optical path length from said initial position is substantially zero and the power density is high with minimal diffraction effects, phase distortion and beam intensity fluctuations, said apparatus comprising: means for amplifying the laser beam; and means positioned in selected spaced relation to said amplifying means for optically relaying the beam, said optically relaying means consisting of at least one pair of lenses positioned at a distance from each other equal to the sum of the focal lengths of the pair of lenses, and means defining a pinhole positioned substantially at a common focal plane of said pair of lenses, such that the laser beam amplified by said amplifying means is optically relayed from one position to a downstream position with minimal effective optical path length difference between said one position and said downstream position and minimal nonlinear diffraction effects, phase distortion and beam intensity variation.

Claim 6

An apparatus for optically relaying a laser beam from an initial position where the power density is low through a plurality of high power amplification stages to a downstream position where the effective optical path length from said initial position is substantially zero and the power density is high with minimal diffraction effects, phase distortion and beam intensity fluctuations, said apparatus comprising: means for amplifying the laser beam; and means positioned in selected spaced relation to said amplifying means for optically relaying the beam, said optically relaying means consisting of at least one pair of lenses positioned at a distance from each other equal to the sum of the focal lengths of the pair of lenses, and means defining a pinhole positioned substantially at a common focal plane of said pair of lenses, such that the laser beam amplified by said amplifying means is optically relayed from one position to a downstream position with minimal effective optical path length difference between said one position and said downstream position and minimal nonlinear diffraction effects, phase distortion and beam intensity variation.

Claim 8

A method for optically relaying a laser beam from one position through a plurality of amplification stages to a downstream position with minimal effective optical path length difference between said one position and said downstream position and minimal diffraction effects nonlinear phase distortion and beam intensity variation, comprising the steps of: directing the laser beam through a plurality of amplification stages, and positioning an optical relay assembly intermediate and in selected spaced relationship to each of the plurality of amplification stages for a substantially zero effective optical path length.

Claim 9

A method for optically relaying a laser beam from one position through a plurality of amplification stages to a downstream position with minimal effective optical path length difference between said one position and said downstream position and minimal diffraction effects nonlinear phase distortion and beam intensity variation, comprising the steps of: directing the laser beam through a plurality of amplification stages, and positioning an optical relay assembly intermediate and in selected spaced relationship to each of the plurality of amplification stages for a substantially zero effective optical path length.