Kilohertz laser ablation for doping helium nanodroplets

Area of Science:

• Atomic and Molecular Physics
• Laser Science and Photonics
• Materials Science

Background:

• Helium nanodroplets (HeNDs) are valuable for studying weakly interacting systems.
• Doping HeNDs with specific atoms or molecules is crucial for various spectroscopic techniques.
• Existing doping methods have limitations in efficiency and material compatibility.

Purpose of the Study:

• To present a new, efficient, and stable setup for doping helium nanodroplets using laser ablation.
• To characterize the doping process and identify different laser ablation regimes.
• To demonstrate the applicability of the doped HeNDs for spectroscopic analysis.

Main Methods:

• Utilized a kilohertz repetition rate laser ablation system for doping.
• Characterized the doping process by analyzing ablation regimes.
• Performed beam depletion spectroscopy on lithium atoms attached to HeNDs.
• Attempted doping with refractory materials (titanium, tantalum) and nonvolatile biomolecules (guanine).

Main Results:

• Identified two distinct regimes of laser ablation during the doping process.
• Demonstrated the efficiency and stability of the setup for spectroscopic applications.
• Successfully doped HeNDs with high-temperature refractory materials like titanium and tantalum for the first time.
• Achieved efficient doping with guanine, detecting various oligomers.

Conclusions:

• The developed laser ablation setup is a versatile and effective tool for doping helium nanodroplets.
• This method opens new avenues for spectroscopic studies of atoms, refractory elements, and biomolecules encapsulated in HeNDs.
• The ability to dope with guanine and its oligomers suggests potential applications in studying DNA-related structures.