Introduction to Nonimaging Optics, 2nd Edition

11

Infinitesimal Étendue Optics

11.1 Introduction

The Simultaneous Multiple Surface (SMS) design method allows us to design two optical surfaces simultaneously that couple two input wavefronts onto two output wavefronts. Here, we consider the limit case, in which the étendue of the light captured by an optic goes to zero. When that happens, the emitter and receiver sizes become infinitesimal. In the case of a solar concentrator, the acceptance angle goes to zero.

In this limit case, we can still design two optical surfaces simultaneously, but the design process is simpler, more stable, and does not have loops that sometimes appear in the SMS. These characteristics make this an interesting design method when the receiver is very small, ...