Hybrid lenses are being frequently used in infrared systems, primarily forcolor correction. We shall analyze one such lens, which is the third element of the MWIR objective shown in Fig. 18.1.
The prescription of the diffractive surface (front surface) is as follows:
1. Radius R 1 =21.246406mm
2. Conic constant Îº 1 =â0.151513 (prolate ellipse)
3. Phase coefficient P 2 =â5975.55048.
4. S 2 =Î»P 2 2ÏR 2 0 =0.004Ã(â5975.550548) 2ÏÃ100 2 =â3.804Ã10 â4
5. Free aperture D=11.84mm
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