What is it?

Program allows to process the results of experiments on the measurement of frequency-angular spectra and integrated frequency spectra of laser pulses after propagation in a nonlinear medium.

Typical plots

Frequency-angular spectrum (FAS) - measurement of the pulse beam spectrum at different angles of its propagation

FAS for Gaussian beam	FAS for vortex beam

Frequency spectrum at constant angle	Angular spectrum at constant wavelength

Integrated frequency spectrum (IFS) - focusing all spatial garmonics and its spectrum measurement

IFS in log scale	IFS in linear scale

Principal design of experiments

FAS	IFS

Installation

• Windows:

virtualenv .venv
cd .venv/Scripts
activate
pip install -r <path_to_project>/requirements.txt

• Linux

virtualenv .venv -p python3
cd .venv/bin
source ./activate
pip install -r <path_to_project>/requirements.txt

Usage

To build the frequency-angular / intergrated frequency spectrum, you must create an object of class ProcessorFAS / ProcessorIFS:

fas = ProcessorFAS(<path_to_experimental_data>)
ifs = ProcessorIFS(<path_to_experimental_data>)

There are 2 command line arguments:

• global_res_dir - path to the directory where a set of program results will be stored
• res_dir_name - name of the directory where a set of program results will be stored At the next start of the program it is checked whether the directory global_res_dir/res_dir_name exists, and if not, a new empty one is created.

Classes ProcessorFAS and ProcessorIFS are derivative for class BaseProcessor, which has the next additional parameters:

• sigma_lambda (default = 10 nm) - dispersion of gaussian filter along lambda coordinate
• log_scale (default = True) - use logarithmic scale or not
• log_power (default = -2) - if log_scale = True, the minimum degree of the logarithm used to plot the spectra

Additional parameters for class ProcessorFAS:

• micron_per_step (default = 10) - number of microns in one step
• deg_per_micron (default = 5 / 3500) - number of degrees in one micron
• sigma_angle (default = 0 rad) - dispersion of gaussian filter along angle coordinate
• steps_overlap (default = 4) - number of overlapping steps in fas measurements
• lambda_dn (default = 50) - number of points along lambda coordinate through which the angular spectrum is plotted

There are no any additional parameters for class ProcessorIFS.

Input

Typical input data for FAS processing (1, 2) and IFS processing (1, 2) is a set of files where wavelengths and the corresponding spectral harmonics intensities are recorded in arbitrary units.