System for amplifying laser beams

Claim 1

A uni-directional laser amplifier system utilizing a diverged, laser beam whose diameter exceeds twenty cm., composed of either a single, unstructured pulse, or a train of such pulses, amplified to a level in excess of one terrawatt peak power over folded amplification path of at least fifty meters emerging via an elliptical cross-section aperture, whose major axis exceeds twenty centimeters the system comprising: (a) two rows spaced at least ten meters apart of amplifying segments of elliptical and progressively increasing cross-sectional area each segment possessing two optically polished, non-parallel, flat end surfaces with the front surface of each segment being anti-reflection coated and its rear surface having either a mirror deposited on it which reflects the laser beam and segment excitation radiation 100% or having the same mirror attached to it and/or separated from the rear surface of the segment by at least half the length of the laser pulse to be amplified so that no pulse overlap occurs in the amplifying medium; (b) each segment orientated at an angle of approximately 45° to the length of its row and at an angle of about 90° to the segment which follows or precedes it in the amplifying sequence so that any pair of segments in the row with their front faces facing each other will reflect the diverged beam traversing the amplifier through a total angle of about 180° the beam traversing each segment twice during this process so that it emerges travelling approximately parallel to its path of incident but in the opposite direction and displaced by at least its own diameter in such a manner that it can traverse all remaining segments of the amplifier system; (c) optical excitation sources for sequential excitation of amplifying segments positioned between the two rows of segments such that each source is positioned parallel to the input surface of its respective segment, at such a distance as not to interfere with the laser beam path, so that its output radiation enters the amplifier segment where it can be partially (or wholly) absorbed and the remainder is wholly reflected by the mirror deposited on the rear surface of the segment so as to increase its absorption efficiency in the laser medium.