Better Together: New 2D X-ray Multilayer Lens Overcomes Alignment Challenge

The Science

Scientists have developed a new type of lens that focuses an X-ray beam to nanometer levels. This is a scale smaller than a single virus. The monolithic 2D multilayer Laue lenses (MLLs) can focus an X-ray beam to approximately 10 nanometers. The system overcomes the alignment challenges typically associated with these ultra-high resolution focusing optics. The 2D optics are based on advances in microfabrication—the methods used to make tiny objects such as computer circuits. The optics provide a robust and compact approach for nanometer-scale resolution X-ray microscopy studies. This development was recognized with a Microscopy Today Innovation Award in 2022.

The Impact

Ultrabright X-ray beams from modern synchrotron light sources are powerful research tools. However, focusing such beams to nanometer sizes requires highly precise and stable optics. These optics can be challenging to keep aligned. The optics described here combine microfabrication technologies with advanced ultra-high resolution focusing optics. This results in single-piece, easy-to-use 2D MLLs focusing elements. These MLLs solve the alignment issue, allowing broader application of the optics in X-ray microscopy.

Summary

Microelectronics and tiny qubits for quantum computers are technologies of the future that can tackle society’s biggest challenges. However, to develop these minuscule powerhouse devices, researchers need to study them at the nanoscale. One efficient, non-destructive way is to use ultrabright X-ray beams available at Department of Energy Office of Science user facilities such as the National Synchrotron Light Source II (NSLS-II). To allow researchers to “see” into these tiny devices, scientists at NSLS-II developed a 2D X-ray optic that focuses hard X-rays down to  approximately 10 nanometers. This development overcomes the alignment challenge for sets of individual 1D multi-layer Laue lenses (MLLs) and makes MLLs more accessible for a broader X-ray microscopy community.

The team manufactured two independent lenses, which are at present the most efficient 1D hard X-ray focusing optics available. They assembled the lenses into a pre-aligned 2D lens by using microfabrication technologies. By leveraging the high accuracy of microfabrication, the researchers achieved stringent alignment requirements between two MLLs. Using this aligned set of lenses, the team successfully demonstrated a point focus of approximately 10 nm at the Hard X-ray Nanoprobe Beamline at NSLS-II. The optic has been recognized as one of the top ten microscopy innovations of the year in 2022 by the science magazine Microscopy Today.

Funding

This work was partially carried out at the Center for Functional Nanomaterials and the National Synchrotron Light Source II, both of which are Department of Energy Office of Science user facilities. This work was also performed in part at the Advanced Science Research Center NanoFabrication Facility of the Graduate Center at the City University of New York.