Generalized Optical Design of the Double-Row Circular Multi-Pass Cell

Area of Science:

• Optics
• Optical Engineering
• Spectroscopy

Background:

• Traditional circular multi-pass cells (CMPC) have limitations in achieving long optical path lengths (OPL) within compact designs.
• Increasing the number of passes in CMPC often leads to reduced spatial separation between optical systems and increased aberrations.

Purpose of the Study:

• To introduce a new design of circular multi-pass cells (CMPC) with two rows of reflection spots on mirrors.
• To enhance the effective optical path length (OPL) and improve spatial separation in multi-pass optical systems.
• To analyze and verify the performance of the novel double-row CMPC (DR-CMPC) design.

Main Methods:

• Analytical chief ray tracing analysis.
• Generalized method for parameter determination for cell design.
• ABCD matrix method for stability analysis.
• Ray tracing simulations for performance verification.

Main Results:

• The novel DR-CMPC design achieves double the effective OPL of traditional CMPC with the same diameter and spot interval.
• Designs with maximum effective OPLs of 74.72 m, 48.67 m, and 24.57 m were demonstrated within a 25 cm diameter DR-CMPC.
• Regular OPL intervals of 1 m are achievable with simple rotational adjustments.
• The DR-CMPC design exhibits significantly reduced astigmatism (e.g., 9.30 × 10⁻⁶ mm for 74.72 m OPL), four orders of magnitude lower than traditional CMPC.

Conclusions:

• The DR-CMPC design effectively doubles the OPL while maintaining or improving optical quality.
• This design provides adequate spatial separation for pre- and post-transfer optical systems, even with a large number of passes.
• The DR-CMPC offers a promising solution for applications requiring long path lengths in compact optical systems with minimal aberrations.