摘要 |
<p>A radiation detector (2) for detecting infrared radiation, which radiation detector (2) comprises: (i) an enclosure (4) having means (6) through which a radiation beam can enter the enclosure (4); (ii) at least two radiation-sensitive devices (10, 12) which produce electrical signals responsive to impinging radiation, and which are positioned inside the enclosure (4) such that (a) the radiation beam can impinge upon a first one of the radiation-sensitive devices (10, 12) and be partially absorbed by that radiation sensitive device, (b) any non-absorbed radiation is reflected from the first radiation-sensitive device to the next radiation sensitive device, and (c) the non-absorbed radiation from the last radiation-sensitive device is reflected back over the same path towards the first one of the radiation-sensitive devices; and (iii) an output means (22) for providing external access to an electrical signal produced by the radiation-sensitive devices (10, 12); and the radiation detector (2) being such that the radiation-sensitive devices (10, 12) are indium/gallium/arsenide radiation-sensitive devices which enable the radiation detector (2) to detect infrared radiation in the wavelength region of 980-1640 nm.</p> |