| 摘要 |
<p>There is provided a method and apparatus (10) for determining the power output of a laser for wavelengths which are substantially fully absorbed by water, such as the wavelengths produced by carbon dioxide lasers. A rotary member (12) defines a surface of revolution (14) which widens away from an opening (16) to a free edge (18), with the opening being located substantially at the axis of the surface. Means are provided for rotating a member about its axis, and water is brought to the surface through the opening, to form a film running to the free edge. Means (48) are provided for collecting water at the free edge, and the water through-put is measured by suitable means. Further means (70,71) are provided for measuring the water temperature differential arising due to absorbable radiation falling upon the water as it runs overthe surface, and on the basis of the throughput and the temperature differential, the absorbed power, and hence the output of the laser in the wavelength region in question, can be calculated. For CO2 lasers substantially all of the radiation is in the region which is fully absorbed by water, and thus the apparatus and method provided herein are ideal for measuring the power output of lasers of this kind.</p> |
