| 摘要 |
The lens material (L1) is translucent in the range of infra-red radiation to be exploited. The objective (1) may be combined with a divergent lens (2) to make non-focusing system followed by a dichroic mirror (3) to separate an infra-red reception channel from an infra-red emission channel from a laser operating in the near infra-red at about 1.06 micrometres. The shape of the hologram is defined by a circle of radius, h, and by a phase function equal to (h2/2f), modulo (L/n-1) where f is its focal length, L is the mean wavelength and n is the refractive index of the medium of the first lens. (L/n-1) is the thickness of the hologram. |
