Source code for pynlo.utility.chi1
# -*- coding: utf-8 -*-
"""
Conversion functions and other calculators relevant to the linear
susceptibility.
"""
__all__ = ["n_to_beta", "beta_to_n", "D_to_beta2", "beta2_to_D"]
# %% Imports
from scipy.constants import pi, c
#%% Converters
# TODO: forward and backward transformations, test with equivalents from medium.Mode
#---- Wavenumber and Linear Susceptibility chi1
def chi1_to_k(v_grid, chi1):
k = 2*pi*v_grid/c * (1 + chi1)**0.5
alpha = 2*k.imag
beta = k.real
return beta, alpha
def k_to_chi1(v_grid, beta, alpha=None):
if alpha is None:
k = beta
else:
k = beta + 1j/2 * alpha
return (c/(2*pi*v_grid) * k)**2 - 1
#---- Phase Coefficient and Refractive Index
[docs]
def n_to_beta(v_grid, n):
"""
Refractive index to phase coefficient.
Parameters
----------
v_grid : array_like of float
The frequency grid.
n : array_like of float
The refractive indices.
Returns
-------
beta
"""
return n * (2*pi*v_grid/c)
[docs]
def beta_to_n(v_grid, beta):
"""
Phase coefficient to refractive index
Parameters
----------
v_grid : array_like of float
The frequency grid.
beta : array_like of float
The angular wavenumbers.
Returns
-------
n
"""
return beta / (2*pi*v_grid/c)
#---- GVD and Dispersion Parameter D
[docs]
def D_to_beta2(v_grid, D):
"""
Dispersion parameter D to group velocity dispersion beta_2 (GVD).
Parameters
----------
v_grid : array_like of float
The frequency grid.
D : array_like of float
The dispersion parameter D, in units of ``s/m**2``.
Returns
-------
The GVD, in units of ``s**2/m``.
"""
return D / (-2*pi * v_grid**2/c)
[docs]
def beta2_to_D(v_grid, beta2):
"""
Group velocity dispersion beta_2 (GVD) to dispersion parameter D.
Parameters
----------
v_grid : array_like of float
The frequency grid.
beta2 : array_like of float
The GVD parameter, in units of ``s**2/m``.
Returns
-------
The dispersion parameter, in units of ``s/m**2``.
"""
return beta2 * (-2*pi * v_grid**2/c)
# %% Calculator Functions
def linear_length():
pass #TODO
