摘要 |
A multi-band refractive optical imaging system. In one example, the system includes a plurality of lenses configured to receive and propagate electromagnetic radiation in at least the visible spectral band and the longwave infrared (LWIR) spectral band, the plurality of lenses including a first group of lenses of a first crown material, at least one lens of a first flint material, and at least one lens of a second material different than the first crown material and the first flint material. The plurality of lenses includes at least one crown-flint pair configured as an achromat to provide color correction in the visible and/or LWIR spectral bands. The system also includes a first beamsplitter configured to separate the electromagnetic radiation into the visible spectral band and the LWIR spectral band, and a rear external aperture stop positioned between the plurality of lenses and the first beamsplitter. |