Applied Digital Optics: From Micro-optics to Nanophotonics

11

Digital Optics Modeling Techniques

Chapters 3–10 have described the digital optical elements used in industry today, as well as the various design techniques used today to calculate, design and optimize them.

This chapter will focus on the various numerical tools available to the optical engineer to accurately model the behavior of the digital optics designed with the techniques described in the previous chapters. Such software tools include CAD programs used to model the effects of illumination and opto-mechanical tolerancing as well as the effects of systematic fabrication errors. Chapters 12–15 describe systematic fabrication errors linked to the various fabrication techniques and technologies investigated throughout this book.

The first section will deal with ray-tracing techniques, whereas the second section will deal with more complex numeric propagators specifically adapted to the modeling of digital diffractives in the scalar diffraction regime. When the diffractive element is composed of structures the dimensions of which are in the vicinity of the wavelength, or the reconstruction window lies very close to the diffractive, more complex vector electromagnetic techniques should be used, and are described in Section 11.3.

Figure 11.1 shows the realm of validity of ray tracing, scalar and semi-scalar propagators and vector EM methods for the modeling of diffractives, as a function of the ratio between the smallest grating period in the diffractive (Λ) and the reconstruction ...