pymatj / pygtm

Python-based Generalized Transfer Matrix method for light propagation in arbitrary anisotropic multilayer stacks

Welcome to GTM documentation

This program implements the generalized 4x4 transfer matrix (GTM) method poposed in Passler, N. C. and Paarmann, A., JOSA B 34, 2128 (2017) and corrected in Passler, N. C. and Paarmann, A., JOSA B 36, 3246 (2019). A Matlab code can be downloaded on zenodo.

As of March 2020, it furthers implements the layer-resolved absorption method proposed in Passler, N. C., Jeannin, M. and Paarmann, A., A Matlab code is also available for this update on zenodo.

This Python implementation also relies on inputs from D. Dietze's FSRStools code https://github.com/ddietze/FSRStools

Please cite the associated publications if you use this code.

author: Mathieu Jeannin
email: [email protected]
affiliations: Laboratoire de Physique de l'Ecole Normale Superieure (2019)
Centre de Nanosciences et de Nanotechnologies (from 2020)

Installation

You should be able to install using pip install . or running python setup.py install, from the project root directory. Otherwise just copy the GTM folder somewhere where python will find it or add the path to your PYTHONPATH variable.

Prerequisite: NumPy, SciPy, Matplotlib

Documentation

See the manual on Read The Docs for the documentation.

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Copyright (C) Mathieu Jeannin 2019-2023 [email protected].

pygtm's Issues

Detection of birefringes

Hi again,

a question regarding the sorting of the qs:

pyGTM/GTM/GTMcore.py

Line 504 in 1f62af2

if np.abs(Cp_t1-Cp_t2) > qsd_thr: ## birefringence

this statement is used to detect birefringes for a layer and to decide if eq (13) or (15) is used for qualculation of the Cps.

I am wondering if the birefringes criterium for a single layer can't be done by checking for off-diagonal elements in the Euler-transformed epsilon 3x3 matrix?

in the best case one saves to calculate Cp_t1 and Cp_t2 and it would be also more simple and intuitive in my opinion.

Best

Daniel

sort berremann qi's according to (12)

Hi @pyMatJ ,

I am currently checking the GTM core code I stumbled a bit over this code here:

pyGTM/GTM/GTMcore.py

Lines 461 to 477 in 1f62af2

	## sort berremann qi's according to (12)
	if any(np.abs(np.imag(qsunsorted))):
	for km in range(0,4):
	if np.imag(qsunsorted[km])>=0 :
	transmode[kt] = km
	kt = kt + 1
	else:
	reflmode[kr] = km
	kr = kr +1
	else:
	for km in range(0,4):
	if np.real(qsunsorted[km])>0 :
	transmode[kt] = km
	kt = kt + 1
	else:
	reflmode[kr] = km
	kr = kr +1

Shouldn't the if-else-case be within the for loop .
As I understood it, you need to sort according to the four cases:

1. complex number with imaginary part >= 0: transmode[0]
2. real number with >= 0: transmode[1]
3. complex number with imaginary part < 0: reflmode[0]
4. real number with < 0: reflmode[1]

Maybe you can check and tell me the idea of the current code.

Thanks

Daniel