Multipass cell design for Stark-modulation spectroscopy.

A multipass cell for absorption measurements with an additionally applied homogeneous electric field for Stark effect measurements is described. The configuration is based on two ring mirrors, where the laser beam propagates between two nested cylindrical-wall electrodes. The total optical path length achieved is 40 m. The beam pointing stability of this setup is investigated and compared to a confocal-type Herriott cell of the same base length, employing numerical simulations. The exit beam pointing stability is found to be very good. The response measurements show fast exchange times, which agree well with theoretical values.