| 摘要 |
A long range laser illuminator is disclosed that is suitable for providing illumination for camera systems at ranges up to approximately 20 km. The illuminator incorporates a diverger that allows for a compact, low F-number optical arrangement that improves eye safety by reducing the power density across a primary optical element, such as a spherical or parabolic mirror. The diverger may be located at an end of an optical fiber feed, or between a pair of optical fibers. The diverger may incorporate a diffuser, such as a “top hat” diffuser. The optical fiber feeds may be highly multi mode, to provide for a more even illumination. The illuminator incorporates means for altering a focus of the output light beam, to allow an illuminated spot size to be altered. The illuminator is particularly suitable for use at night, where it may be used alongside a camera system. |
| 主权项 |
1. A long range illuminator comprising:
a laser source having a laser power output, an optical feed and a primary optical element having an associated optical area, wherein the optical feed is arranged to transfer a light beam from the laser and provide it to the primary optical element to produce an illuminator output, wherein:
the optical feed includes a first optical fibre and a beam diverger, the beam diverger including at least a light diffuser, the beam diverger being arranged to generate, at an output of the optical feed, a cone of light to the primary optical element of a substantially uniform density across the optical area,the beam diverger is coupled to the first optical fibre such that light from the beam diverger passes into the first optical fibre, the first optical fibre being arranged to provide light to the primary optical element, andthe first optical fibre is a multimode fiber selected to encourage mixing of modes within the fibre as light from the beam diverger passes down the first optical fibre,wherein the primary optical element comprises a reflecting element, and is arranged to provide illumination to a range of at least 30 meter. |
