Table-top soft x-ray microscope using laser-induced plasma from a pulsed gas jet.

Area of Science:

• Physics
• Optics
• Materials Science

Background:

• Soft x-ray microscopy offers high resolution for biological and material samples.
• Existing microscopes can be large and require complex infrastructure.
• The water window (2.3–4.4 nm) is ideal for imaging hydrated biological specimens.

Purpose of the Study:

• To develop an extremely compact soft x-ray microscope.
• To achieve high spatial resolution using a stable, debris-free x-ray source.
• To demonstrate the microscope's imaging capabilities in the water window.

Main Methods:

• Utilizing a pulsed nitrogen gas jet laser-induced plasma as a stable, debris-free soft x-ray source.
• Employing an ellipsoidal grazing incidence condenser mirror for focusing.
• Using a Fresnel zone plate for imaging onto a CCD camera with magnifications up to 500x.

Main Results:

• Demonstrated a compact soft x-ray microscope operating at 2.88 nm wavelength.
• Achieved a spatial resolution of approximately 100 nm, verified with a Siemens star test pattern.
• The laser-induced plasma source proved to be long-term stable and nearly debris-free.

Conclusions:

• The developed compact soft x-ray microscope is a viable tool for high-resolution imaging.
• The use of a nitrogen gas jet laser-induced plasma offers a practical and stable x-ray source.
• This technology advances the accessibility and application of soft x-ray microscopy.