Abstract: Disclosed is an optical amplification device comprising an amplifier medium inserted between two mirrors and an optical pumping source. The mirrors are confocal mirrors whose focal plane is located in the vicinity of the center of the non-linear medium. This medium has a match-stick shape with a large axis in one direction forming an angle alpha/2 with the optical axis of the cavity defined by the two mirrors and the amplifier medium. This architecture enables an incident optical wave to pass several times within the amplification device leading to an increase in the performance characteristics of said device.

Abstract: Mode-locked pulsed output is induced in a laser by introducing a varying frequency dependent loss in the cavity. The varying, frequency dependent loss allows a large number of longitudinal modes to oscillate. In one of the preferred embodiments of the subject invention, the varying frequency dependent loss is generated by reciprocating one of the mirrors of the resonator. In this embodiment, the laser has a resonator with a primary light path defined by first and second end mirrors. A gain medium is located between the end mirrors. A beam splitter is provided for redirecting the light into a secondary light path. A third mirror functions to feed back the light into the primary light path. Pulse formation is induced by varying the path length of one of the two paths by reciprocating an end mirror. Moving the mirror creates varying interference effects when the light energy is recombined at the beam splitter. The mirror is reciprocated relatively slowly, yet ultra-short pulses are generated.