| 摘要 |
This invention allows forcing successive pulses of a pulsed laser to be on different spectral lines. This invention can support a higher pulse repetition frequency than the prior art and the alignment of the laser does not change during a pulse. There are five implementations or embodiments of this invention. The first embodiment includes a set of diffraction gratings (25-30) on the face (24) of a wheel (23) each grating being set at an angle to select a different spectral line. The wheel is rotated, and as each grating moves into the end-reflector position of the laser's optical path, the laser is fired. The second embodiment includes a single fixed diffraction grating (58) and a set of plane mirrors (49-54) on the face (47) of the wheel (45), each mirror being set at an angle to reflect onto the diffraction grating and select a different spectral line. The wheel is rotated and as each mirror moves into the end-reflector position of the laser's optical path, the laser is fired. Alternate embodiments include a small spinning fold mirror (65) that reflects the beam in a circle about the axis (15) of the laser in an embodiment that includes (a) a circular array of diffraction gratings (73, 75) arranged about the laser axis such that the tilt of the gratings and the orientation of the grooves vary as one goes around the circle and successively fires the laser at each grating; (b) both a circular array of mirrors (77-79) and a corresponding array of diffraction gratings (80, 81) such that the grooves of all of the gratings are parallel and the gratings are all tilted in the same direction; and (c) two spinning fold mirrors (59, 59') and two circular arrays of mirrors (77, 79, 87, 89) giving a double fold plus a single diffraction grating (99) wherein the optical paths are not parallel but arrive at the grating at different angles for selecting different spectral lines. |
