Agile beam laser

DETAILED DESCRIPTION In order to overcome the deficiencies in the prior art, the present invention utilizes phase conjugation principles to provide for a steerable laser beam having good beam quality.
The present invention employs the use of a phase conjugate reflector which reflects laser energy that is the phase conjugate of energy incident thereupon.
The phase conjugate reflector is utilized as one end mirror of a laser resonator.
An electronically controlled optical device is employed as the second mirror element of the laser resonator.
The optical device provides for a plurality of selectable transverse lasing modes to exist in the laser resonator.
Each of the transverse lasing modes have a predetermined wavefront tilt in the near field of the laser resonator.
A laser gain medium and its associated pump source are disposed between the optical device and the phase conjugate reflector for providing the laser energy which is reflected inn the resonator.
An output coupling device is disposed adjacent to the optical device in the near field for coupling a portion of the laser energy out of the laser system as an output beam.
The optical device may comprise a focusing lens and a mirror located at the focal plane of the lens.
The mirror is one whose dimension is approximately one diffraction spot in size, and whose transverse location in the focal plane is electronically controlled to control wavefront tilt.
By selectively controlling the position of the reflecting surface, different transverse modes of the laser will lase between the phase conjugate reflector and the mirror in the optical device.
Selective control over the transverse mode which is lasing in the resonator results in a steerable output beam whose position in the far field is determined by the location of the mirror in the focal plane of the optical device.
A second embodiment of the optical device contemplates the use of an electronically controllable spatial filter disposed between lenses and a reflective element disposed as the second end mirror of the resonator