Optically pulsed laser

Claim 1

A laser system comprising a parent standing wave unstable laser resonator having a gain medium, substantially DC pump means for producing a population inversion in said gain medium, mirror means disposed along an axis for directing optical radiation through said gain medium in a magnifying output mode and a demagnifying adjoint mode, a predetermined parent resonator gain threshold for lasing operation, a parent resonator magnification, a parent resonator feedback value, and output means for directing an output beam out of said unstable resonator, comprising; adjoint feedback means having at least one feedback coupling means disposed to intercept radiation in said magnifying output mode, whereby a portion of said radiation in said magnifying output mode passes through said at least one feedback coupling means as an output feedback beam, and for passing through a return feedback coupling means of said at least one feedback coupling means an adjoint mode feedback beam mode matched to said demagnifying adjoint mode; said adjoint feedback means includes adjoint feedback reflection means for receiving said output feedback beam passed through said feedback coupling means and for feeding back through said return feedback coupling means said adjoint mode feedback beam mode matched to said demagnifying adjoint mode, whereby radiation in said output mode in said parent resonator is coupled to said adjoint mode in said parent resonator through the passing of said adjoint mode feedback beam through said return feedback coupling means, and said laser system comprises a composite resonator including said parent laser resonator and a resonator control leg comprising said adjoint feedback reflection means, said composite laser resonator having a composite feedback with a total feedback value greater than said parent resonator feedback value; feedback beam modulation means are located intercepting said output feedback beam, for alternately obstructing and passing said adjoint mode feedback beam, whereby said resonator control leg comprises said adjoint feedback reflection means and said beam modulation means; said composite laser resonator has said total feedback value when said feedback beam modulation means passes said adjoint mode feedback beam and has said parent resonator feedback value when said beam modulation means obstructs said adjoint mode feedback beam, and said resonator control leg switches a composite feedback value of said composite laser resonator between said parent resonator value and said total feedback value; said pump means has a predetermined capacity at least as great as a cw capacity sufficient to produce cw laser operation in said parent resonator; and said adjoint feedback means is sized and disposed to increase said composite feedback of said composite laser resonator by a predetermined modulation amount from said parent resonator feedback value such that a population inversion in said gain medium produced by said pump means when said adjoint mode feedback beam is blocked by said feedback beam modulation means is depleted by laser oscillation when said feedback beam modulation means passes said adjoint mode feedback beam, whereby lasing in said laser ring resonator is controllably switched by said beam modulation means.