laserfields 0.4.0

Python library for describing time-dependent laserfields by Johannes Feist.

laserfields

laserfields is a library to describe the time-dependent electric fields of a laser pulse. It implements the same pulse shapes and most of the features of the laserfields library written in Fortran. Please see the documentation of that library for the parameter meanings, conventions used, etc. In particular, the "main" function make_laserfield(**kwargs...) accepts the same parameters as the Fortran library parameter files as keyword arguments, and returns an instance of a subtype of the base class LaserField depending on the parameters. E.g., to create a Gaussian pulse with a duration (defined as the FWHM of the intensity) of 6 fs, a wavelength of 800 nm, a peak intensity of 1e14 W/cm^2, and with the peak at time t=7fs, one should call

lf = make_laserfield(form="gaussianI", is_vecpot=true, lambda_nm=800,
                      intensity_Wcm2=1e16, duration_as=6000, peak_time_as=7000)

Given a LaserField instance lf, the functions lf.E(t), lf.E_fourier(ω), lf.A(t), and lf.A_fourier(ω) can be used to obtain, respectively, the electric field as a function of time, its Fourier transform (implemented for most pulse shapes), the vector potential as a function of time, and its Fourier transform. Calling the instance as a function, lf(t) returns the electric field, i.e., is equivalent to lf.E(t). The notebooks in the examples folder show some ways to use the library, including how to define a set of fields through a YAML configuration file.

The "effective" duration of the pulse for n-photon processes can be obtained as lf.Teff(n_photon), which is the integral over the pulse intensity envelope to the n-th power (i.e., electric field envelope to the (2n)th power) over the pulse, see, e.g., https://doi.org/10.1103/PhysRevA.77.043420 (Eq. 14).