Focusing and Diffraction of Light by Periodic Si Micropyramidal Arrays

TL;DR

This paper models the optical properties of silicon micropyramids to optimize their design for infrared light concentration, demonstrating effects like Talbot interference and focusing for photodetectors.

Contribution

It introduces a dual boundary condition modeling approach to analyze and optimize silicon micropyramids for infrared light focusing and concentration.

Findings

Demonstrated Talbot effect in micropyramid arrays

Identified geometries for maximum photonic nanojets

Validated optical focusing properties experimentally

Abstract

This research was devoted to modeling of the optical properties of Si micropyramids aimed at designing optimal structures for applications as light concentrators in mid-wave infrared (MWIR) focal place arrays (FPAs). It is shown that completely different optical properties of such structures can be realized using two types of boundary conditions (BCs): i) periodical and ii) perfectly matched layer. The first type (periodical BC) allowed us to describe the Talbot effect under plane wave coherent illumination conditions. This effect was experimentally demonstrated in the proposed structures. The second type (perfectly matched layer BC) allows describing the optical properties of individual micropyramids concentrating or focusing light on the photodetector. The optimal geometries of micropyramids required for maximizing the intensity of photonic nanojets emerging from their truncated tips are determined.