| 摘要 |
A reflector (38) includes a mirrored surface (48) and a frequency selective surface (46). The frequency selective surface (46) is arranged to reflect radiation of a first frequency band (52) and allow radiation of a second frequency band (50) to pass. The mirrored surface (48) is arranged to reflect radiation of the second frequency band (50). In this manner, the focal power for radiation of the first frequency band (52) is independent to the focal power for radiation of the second frequency band (50). Accordingly, the design of optical components associated with the second frequency band50can be undertaken independently of those associated with the first frequency band (52) so as to achieve the optimised focusing for each frequency band. |
