An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets

Area of Science:

• Physics
• Optical Engineering
• Plasma Science

Background:

• Traditional optical tweezers have limited working distances for laser-matter interaction studies.
• High-intensity laser experiments require stable, precisely positioned micro-targets.

Purpose of the Study:

• To design and construct a novel in-vacuum optical levitation trap for high-intensity laser experiments.
• To enable long-working-distance manipulation and stable positioning of micro-targets.

Main Methods:

• Utilized a focused, vertically propagating continuous wave laser beam for photon momentum transfer trapping.
• Implemented a high-speed (10 kHz) optical imaging system for position tracking with ±5 μm resolution.
• Demonstrated trapping of 10 ± 4 μm oil droplets in vacuum over extended distances (~40 mm).

Main Results:

• Achieved stable optical trapping of microdroplets in vacuum for over 1 hour.
• Maintained droplet alignment with a ~7 μm laser focal spot for up to 5 minutes.
• Successfully used levitated droplets as targets in high-intensity (10^17 W cm^-2) laser experiments, measuring X-ray source size and electron temperature.

Conclusions:

• The developed optical levitation trap provides a robust platform for single, isolated microdroplet targets in high-intensity laser interactions.
• This technology facilitates advanced studies of X-ray generation and plasma diagnostics from micro-scale targets.
• The system's long working distance and stability enhance precision in laser-matter interaction research.