| 摘要 |
For concentrating a laser beam (FR), there is provided a re-phasing at a distance (SF) of the beam emitted with an output having annular geometry, the ratio between the dimension (2) in the azimuthal (in other words tangential) direction of the apertures (13A) and the periodicity (d) of the apertures being less than 1; in particular, there is provided an annular laser with a periodic cavity filter (13) having a parameter (filling factor) DELTA APPROX 0.7 DIVIDED 0.95 and a re-phasing surface at a distance delta F of the order of, for example, a few tens of cm, for a periodicity of a few mm and a wavelength of approximately 10 microns. |
