Talbot images of wavelength-scale amplitude gratings

Myun-Sik Kim,Carsten Rockstuhl,Christoph Menzel,Hans Peter Herzig,Toralf Scharf

doi:10.1364/oe.20.004903

Abstract

By means of experiment and simulation, we achieve unprecedented insights into the formation of Talbot images to be observed in transmission for light diffracted at wavelength-scale amplitude gratings. Emphasis is put on disclosing the impact and the interplay of various diffraction orders to the formation of Talbot images. They can be manipulated by selective filtering in the Fourier plane. Experiments are performed with a high-resolution interference microscope that measures the amplitude and phase of fields in real-space. Simulations have been performed using rigorous diffraction theory. Specific phase features, such as singularities found in the Talbot images, are discussed. This detailed analysis helps to understand the response of fine gratings. It provides moreover new insights into the fundamental properties of gratings that often find use in applications such as, e.g., lithography, sensing, and imaging.

Highlights

Periodic structures diffract light, and such diffracted light interferes in the vicinity of the structure
We experimentally study the diffraction of light by wavelength-scale-period gratings in the Fresnel diffraction regime with a high-resolution interference microscope (HRIM)
The HRIM is reinforced with auxiliary techniques known from conventional microscopy, which are often difficult to be implemented in other types of holographic or interferometric microscopes

Summary

Introduction

Such diffracted light interferes in the vicinity of the structure. The simplest example for a periodic structure is an amplitude grating that diffracts the light into discrete directions. In the Fresnel diffraction regime, these diffraction orders interfere and cause a self-imaging phenomenon of the grating. This phenomenon is known as the Talbot effect, named in honor of his discovery by F. Talbot in 1836 [1].

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