Optical path length and trajectory stability in rotationally asymmetric multipass cells

Area of Science:

• Optics and Photonics
• Optical Engineering
• Laser Cavity Design

Background:

• Multipass cells are crucial for enhancing light-matter interactions by increasing optical path length within a confined volume.
• Existing multipass cells, such as cylindrical and astigmatic Herriott cells, have limitations in achieving high path length to volume ratios.
• Designing rotationally asymmetric cavities (RACs) for long optical paths requires sophisticated methods.

Purpose of the Study:

• To describe the behavior of optical trajectories in multipass rotationally asymmetric cavities (RACs).
• To demonstrate a method for generating significantly long optical paths within a compact volume.
• To simplify the design process for RACs with extended optical path lengths.

Main Methods:

• Utilized a phase-space motivated approach to analyze optical trajectories.
• Investigated the generation of long optical paths within multipass RACs.
• Studied the sensitivity of optical path length to input condition variations.

Main Results:

• Achieved an optical path length of 18 meters within a 68 cm³ volume.
• Obtained a path length to volume ratio of 26.6 cm⁻², significantly exceeding current state-of-the-art multipass cells (e.g., cylindrical: 6.6 cm⁻², astigmatic Herriott: 9 cm⁻²).
• Compared the stability of optical paths in RACs to astigmatic Herriott cells.

Conclusions:

• The phase-space approach simplifies the design of RACs for achieving long optical paths.
• The demonstrated method offers a superior path length to volume ratio compared to existing technologies.
• This work has the potential to enable broader implementation of multipass cells in various applications.