Linear Scalability of Dense-Pattern Herriott-type Multipass Cell Design

Multipass cells (MPC) have been widely used for high-sensitivity spectroscopic measurements. We report the linear scalability in the configuration design of an MPC, which is derived from ray transfer equations in the non-paraxial approximation. As a proof of principle, twelve sets of Herriot-type cells ranging from 4.6 × 4.6 × 12.3 to 57.1 × 57.1 × 147.7 mm3 were investigated with their beam patterns and optical path lengths modeled. By taking the non-intersecting seven-circle beam pattern as a typical example, the designated beam patterns were successfully reproduced by modeling and the optical path length scales linearly with the cell size. Two sets of MPCs were also fabricated by additive manufacturing to further justify the rationale of linear scalability. Possible effects of beam spot size and the signal-to-noise ratio on the miniaturization and escalation of MPCs were discussed. This work contributes to a new insight into the cell configuration and will be useful for accelerating the cell design at various scales.