PyTASER

The library is undergoing changes before it is released

Official Documentation

PyTASER is a Python (3.9+) library built for simulating transient absorption spectroscopy (TAS) features from DFT calculations. The goal of this library is to simulate TAS spectra for comparison with and interpretation of experimental spectra. The main features include:

• A TAS spectrum for a pristine semiconducting crystal
• Components from individual band-to-band transitions
• Spectra for different conditions: temperature and carrier concentrations
• Consideration of non-magnetic and magnetic materials
• Capability to input calculated bandstructure and density of states inputs with support for the Materials Project

Installation

To install the module with pip (recommended):

pip install --user pytaser

To install directly from the git repository:

pip install --user git+https://github.com/WMD-group/PyTASER

To do a manual build and installation:

python3 setup.py build
python3 setup.py install --user

PyTASER is currently compatible with Python 3.9+ and relies on a number of open-source python packages, specifically:

• pymatgen
• numpy, scipy for data structures and unit conversion
• matplotlib for plotting the spectra

Developer’s installation (optional)

For development work, PyTASER can also be installed from a copy of the source directory:

Download PyTASER source code using the command:

git clone https://github.com/WMD-group/PyTASER

Navigate to root directory:

cd PyTASER

Install the code with the command:

pip install -e .

This command tries to obtain the required packages and their dependencies and install them automatically.

Visualisation

The preferred method is to generate a Jupyter Notebook, as shown in the examples folder. Alternatively, you can set up a file in Python to run it in the command line of the terminal:

python3 <filename.py>

Contributing

We appreciate any contributions in the form of a pull request. Additional test cases/example spectra performed with PyTASER would be welcomed. Please feel free to reach out to us if there are any questions or suggestions.

Future topics we plan to build on:

• Incorporating finite-temperature effects (particularly for indirect bandgaps)
• Description of more complex optical processes (e.g. stimulated emission)
• Direct treatment of pump-probe time delay
• Incorporating spin-flip processes for spin-polarised systems
• Description of defective crystals

Acknowledgements

The project was the focus of a UROP by @savya10, supervised by @utf and @aronwalsh, with on-going developments and testing from @kavanase and @youngwonwoo.