Access to SPIE eBooks is limited to subscribing institutions. Access is not available as part of an individual subscription. However, books can be purchased on SPIE.Org
Abstract
5.1 Introduction The progression of an achromat from the basic conventional form to a diamondturned aspheric hybrid for the infrared spectrum will be demonstrated in this Chapter. We start with a cemented doublet for the visible spectrum, then change to the mid-wave and long-wave infrared regions, and proceed with the rest of the improvements relating to aberration reductions in the long-wavelength spectral band. For this exercise, we elect a 100-mm focal length with an f∕4 relative aperture and add a field of ±2 deg. 5.2 Thin Achromat for the VIS Spectrum, On-Axis Performance A conventional achromat consist of two elements. One has positive power and a low relative dispersion (high Abbe number), the other has negative power and a high relative dispersion (low Abbe number). The elements' powers, required for chromatic aberration correction, are ϕ a =V a (V a −V b ) ϕ for the front element, and ϕ b =V b (V b −V a ) ϕ for the rear element. V a andV b are the mentioned Abbe numbers for the two elements.
Online access to SPIE eBooks is limited to subscribing institutions.
CHAPTER 5


SHARE
Back to Top