Experimental challenges for high-mass matter-wave interference with nanoparticles

TL;DR

This paper discusses recent progress and experimental challenges in conducting matter-wave interference experiments with large nanoparticles, focusing on source development, detection, and beam splitting techniques to push mass limits.

Contribution

It introduces a universal magnetron sputtering source and photoionization gratings for coherent beam splitting and detection in high-mass nanoparticle interference experiments.

Findings

Development of a universal nanoparticle source with low velocity spread

Implementation of photoionization gratings as beam splitters

Design of an upgraded Talbot-Lau interferometer for larger masses

Abstract

We discuss recent advances towards matter-wave interference experiments with free beams of metallic and dielectric nanoparticles. They require a brilliant source, an efficient detection scheme and a coherent method to divide the de Broglie waves associated with these clusters: We describe an approach based on a magnetron sputtering source which ejects an intense cluster beam with a wide mass dispersion but a small velocity spread of 10%. The source is universal as it can be used with all conducting and many semiconducting or even insulating materials. Here we focus on metals and dielectrics with a low work function of the bulk and thus a low cluster ionization energy. This allows us to realize photoionization gratings as coherent matter-wave beam splitters and also to realize an efficient ionization detection scheme. These new methods are now combined in an upgraded Talbot-Lau interferometer with three 266 nm depletion gratings. We here describe the experimental boundary conditions and how to realize them in the lab. This next generation of near-field interferometers shall allow us to soon push the limits of matter-wave interference to masses up to 10 megadaltons.