clerq

clerq is a Python package for solving the coupled Maxwell–Bloch equations describing the nonlinear propagation of near-resonant light through thermal quantised systems such as atomic vapours.

Propagation of a 4π pulse through a dense atomic vapour. The pulse immediately breaks up on entering the medium and the resultant pulses form two optical solitons each with a pulse area of 2π.

clerq is used for theoretical research, for modelling experiments and for undergraduate and graduate teaching. It can model two, three or many-level systems with physical effects including:

• Inhomogeneous broadening due to spontaneous decay,
• Doppler broadening in thermal systems,
• Collision dephasing,
• Sub-level structure.

Modules are also available for:

• Generating hyperfine structure for alkali atoms with the correct channels and angular momentum factors for coupling and decay,
• Spectral analysis,
• Plotting and animating solutions.

Some phenomena that can be demonstrated:

• Linear absorption and dispersion,
• Fast light and slow light,
• Electromagnetically Induced Transparency (EIT),
• Storage and retrieval of light pulses,
• Self-Induced Transparency (SIT) and optical solitons,
• Matched pulses and simultons,
• Hyperfine pumping.

See the Examples for details.