# TAS - Transmission spectra with Atom-Surface interactions documentation¶

A Python package tas calculates transmission spectra through optically thin slabs of atomic vapours contained in spectroscopic cells including important effects of thin cells:

• two closely spaced walls of the spectroscopic cell act as low-finesse cavity for driving light and emitted light;
• atoms colliding with the cell walls depolarise, and their subsequent transient dynamics also changes transmission spectra; finally
• atom-surface van der Waals interaction induces level shifts. For thickness smaller than λ/(2π), where λ is the wavelength of the strongest dipole allowed transition from each of the two energy levels whose transition spectrum we explore, the shift of the transition energy is $$\propto C_3/R^3$$, where $$C_3$$ is van der Waals constant for given atomic transition.

Generated spectra can be used for fitting results of atom-vapour laser spectroscopy to obtain strength of $$C_3$$ for atom-surface interactions. Detailed documentation follows bellow. For detail on the physics and measurements please cite original paper.

## Credits¶

Authors: Tom Peyrot and Nikola Šibalić BSD-3 0.0.1 of 2019/04/17