Coherent diffractive imaging beyond the projection approximation: waveguiding at extreme ultraviolet wavelengths

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Understanding light propagation in nanostructures is crucial for advanced optical devices.
• Extreme-ultraviolet (EUV) light offers unique properties for nanoscale imaging and manipulation.

Purpose of the Study:

• To investigate extreme-ultraviolet wave propagation within optically thick nanostructures.
• To visualize and characterize EUV guided modes and scattering phenomena at the nanoscale.

Main Methods:

• High-resolution coherent diffractive imaging (CDI) utilizing high-harmonic radiation.
• Phase retrieval algorithms for reconstructing exit waves from nanostructured samples.
• Numerical and semi-analytical simulations for validating experimental observations.

Main Results:

• Waveguiding was identified as the dominant mechanism for EUV wave propagation within the nanostructures.
• Direct visualization of EUV guided modes was achieved.
• Multiple scattering was observed as a common characteristic in extruded nanoscale geometries.

Conclusions:

• CDI with high-harmonic radiation is a powerful tool for studying EUV wave phenomena in nanostructures.
• Waveguiding and multiple scattering are key features of EUV propagation in nanoscale geometries.
• The experimental findings are consistent with theoretical and simulation models.