title: Extra-cavity feedback into unstable resonators.
abstract: Unstable resonators constructed of totally reflecting optics are particularly sensitive to extra-cavity feedback. This is demonstrated experimentally by reflecting the attenuated output of an injection mode-locked TEA CO(2) laser, fitted with a confocal unstable resonator, back into the laser resonator. Even after attenuation by ~10(6), significant perturbation ( greater, similar10%) could be observed in the temporal characteristics of the output train. A theory of extra-cavity feedback in the geometric limit is presented.
authors.forename: P B
authors.initials: PB
authors.lastname: Corkum
authors.forename: H A
authors.initials: HA
authors.lastname: Baldis