A Microscope That Maps Chemical Compositions in 3D
Researchers affiliated with the Center for Extreme Ultraviolet Science and Technology (ERC EUV), an NSF-funded Engineering Research Center headquartered at Colorado State University, have combined extreme ultraviolet laser ablation and mass spectrometry to demonstrate for the first time a microscope that maps chemical composition in 3D with nano-scale resolution and high sensitivity.
Visualizing the composition of nano-scale objects in three dimensions offers revolutionary insight into the biochemistry of these complex systems. Microscopes allow one to “see” the shape and morphology of objects but are incapable of assessing chemical composition. The ERC's extreme ultraviolet laser provides an imaging system with the capability to probe the chemical composition of single cells or microorganisms at the nano-scale level.
A focused extreme ultraviolet laser was used to ablate extremely small holes on a solid sample, and the ablated material was analyzed by mass spectrometry. The figure shows the composition map of a heterogeneous sample containing gold pillars grown onto an indium-tin-oxide covered glass substrate and immersed in photo-resist. The composition map shows the distribution of each of the materials obtained from the analysis of consecutive single-shot ablation events. The technique has been demonstrated to map composition with resolution of 140 nm lateral and 50 nm depth.