Radiation generator.

摘要

A radiation generator in which substantially all the radiation modes are locked with respect to one another comprises a radiation generating cavity defined by mirrors (2,3) and a crystal (1) for generating a continuous train of non-transform limited pulses of coherent radiation. An external cavity (7) is positioned in association with the radiation generating cavity whereby radiation may pass in use in both directions between the two cavities. The external cavity (7) is defined by a medium (8) having a non-linear transmission characteristic which may be substantially non-dispersive for radiation from the generating cavity, and/or which has a negative group delay dispersion. The radiation path length is such that the external cavity (7) whereby radiation transmitted through the external cavity is fed back by the feedback means to the radiation generating cavity.