In Situ SEM-Raman with Waviks Vesta: 6 Published Studies

The Waviks Vesta system is enabling a new class of in situ electron microscopy experiments by bringing laser delivery and Raman spectroscopy directly into the SEM and STEM column, allowing researchers to process, modify, and spectroscopically probe materials without breaking vacuum or transferring samples. The following six published studies from leading national laboratories and universities demonstrate the breadth of research that this in situ SEM-Raman capability unlocks.

Revealing Laser-Thin Film Interactions In Situ

Understanding how laser energy interacts with thin film materials at the nanoscale requires observation in real time, under the conditions where those interactions occur. Unocic and colleagues used the Waviks Vesta to deliver controlled laser illumination to thin film samples inside the electron microscope while simultaneously imaging the resulting structural and morphological changes.

This in situ approach revealed transient phenomena, including phase transformations, ablation thresholds, and heat-affected zone evolution, that would be invisible in conventional ex situ characterization where samples are processed and then transferred to a separate microscope for examination. The ability to observe these dynamics as they happen fundamentally changes the quality of information available to researchers studying laser-materials interactions.

Direct-Write Materials Processing Inside the Microscope

Lasseter’s doctoral research, spanning multiple publications, established a comprehensive framework for using the Waviks Vesta as an in situ direct-write fabrication tool inside electron microscopes. The 2022 ACS Applied Nano Materials paper demonstrated selected-area deposition of platinum-carbon nanostructures using laser-assisted decomposition of organometallic precursors, with the electron beam providing real-time imaging of the deposition process.

The full dissertation expanded this work to explore broader direct-write processing methods, including laser-induced modifications and patterning at the nanoscale. By combining laser delivery with simultaneous electron beam imaging, the Waviks Vesta enabled closed-loop fabrication where researchers could observe and adjust processing parameters in real time rather than relying on iterative trial-and-error between separate processing and characterization steps.

Versatile Laser Delivery for STEM Research

Dyck and colleagues at Oak Ridge National Laboratory published two complementary studies demonstrating the versatility of the Waviks Vesta for scanning transmission electron microscopy applications. The Advanced Materials paper presented the system as a general-purpose side-entry laser platform for STEM, detailing the optical design and demonstrating multiple operational modes including laser heating, photon-stimulated processes, and combined laser-electron beam experiments.

The companion Microscopy and Microanalysis paper focused specifically on in situ laser ablation as a sample preparation and modification technique for electron beam fabrication workflows. By using the Vesta’s laser to selectively remove material, researchers created starting geometries for subsequent e-beam nanofabrication, combining subtractive laser processing with additive beam-induced deposition in a single vacuum session.

Why Side-Entry Laser Matters

Conventional approaches to introducing laser light into electron microscopes typically require extensive custom modifications to the column or specimen stage. The Waviks Vesta’s side-entry design provides laser access through the standard specimen port, making it compatible with existing microscope infrastructure and dramatically reducing the barrier to adopting in situ laser capabilities.

Stimulated Electron Energy Gain and Loss Spectroscopy

Wolf and colleagues pushed the boundaries of electron spectroscopy by using the Waviks Vesta to deliver precisely timed laser pulses that interact with the electron beam inside the microscope. In stimulated electron energy gain and loss spectroscopy, photons from the laser either add energy to or remove energy from passing electrons, creating measurable shifts in the electron energy loss spectrum that encode information about the optical and electronic properties of the specimen.

This advanced technique requires extremely precise spatial and temporal overlap between the laser and electron beams, a capability that the Waviks Vesta was specifically engineered to provide. The study demonstrated new spectroscopic modes that are only accessible when laser and electron probes are co-aligned on the same sample region under vacuum.