OptStrata module¶
This module contains MaxwellLayer and OptStrata classes. The physics model can be seen in Physics Model and Formulas: Optic tab
MaxwellLayer is a transfer matrix solver for 1D optical stabs, OptStrata is a wrapper of MaxwellLayer with material information coded.
OptStrata classes¶

class
OptStrata.
MaxwellLayer
(wl: float, Ls: List = [1.0, 1.0], allIndex: List = [1.0, 1.0])¶ Class for layer structure for Maxwell solver using transfer matrix method
 Parameters

boundModeTM
(beta: Optional[complex] = None) → complex¶ Solve for TM bounded mode near beta
Solve for TM bounded mode near beta (as first guess in root finding) with frequency \(\omega = c/\text{wl}\) on the stratum structure discribed with the thickness and index list; top/substrate defined by index0 and indexs. wl and Ls should be same unit
 Parameters
beta (complex) – The effective refractive index traveling along z (initial guess)
 Returns
complex – the effective refractive index for bounded mode
:raises Exception:: The solver doesn’t converge. Most likely a bounded mode doesn’t exist.

chiMTM
(beta: complex) → complex¶ Modaldispersion function for TM wave
Calculate the with modaldispersion function for TM wave with frequency \(\omega = c/\text{wl}\) on the stratum structure described with the thickness and index list; top/substrate defined by index and index. wl and Ls should be same unit
 Parameters
beta (complex) – The normalized wavenumber along z. \(k_z = 2\pi/\lambda*\beta\)
 Returns
complex – The modaldispersion function

confinementy
(beta: complex, ars: List[numpy.ndarray], xs: Optional[numpy.ndarray] = None, Ey: Optional[numpy.ndarray] = None) → float¶ Return the confinement factor corresponds to mode with effective refractive index beta. Assuming active only couple to E_y filed. The active region is defined in ars. If xs and Ey is None, they will be generated.
 Parameters
beta (complex) – The refractive index of the mode to calculate
ars (list(np.ndarray(bool))) – The list of active region for confinement factor
xs (np.ndarray) – The array for positions: controls the accuracy of the numerical integral for confinement facotr calculation
Ey (np.ndarray(complex)) – The field to integral on
 Returns
float – The confinement factor of the structure

populateIndices
(xs: numpy.ndarray) → numpy.ndarray¶ Generate indices position array xs
 Parameters
xs (np.ndarray) – The position coordinate to calculate field on
 Returns
np.ndarray – refractive indices of the material at position xs

populateMode
(beta: complex, xs: numpy.ndarray) → numpy.ndarray¶ Generate TM modes (field) on position array xs
Generate TM modes (field) on position array xs, assuming beta is a bounded Mode (i.e. return value of
boundModeTM()
) return Ey, Hx, Ez, normalized to max(abs(Ey)) = 1; unit of Hx is \(([\text{nit of beta}]\times \sqrt{\mu_0/\epsilon_0})^1\) Parameters
beta (complex) – The effective refractive index traveling along z
xs (np.ndarray) – The position coordinate to calculate field on
 Returns
np.ndarray – E field perpendicular to layers and propagation
np.ndarray – H field parallel to layers and perpendicular to propagation
np.ndarray – E field in propagation

transferTM
(beta: complex) → numpy.ndarray¶ Tranfer matrix for TM wave
Calculate the transfer matrix for TM wave with frequency \(\omega = c/\text{wl}\) on the stratum structure described with the thickness and index list. wl and Ls should be same unit
 Parameters
beta (complex) – The normalized wavenumber along z. \(k_z = 2\pi/\lambda *\beta\)
 Returns
np.ndarray – A 2*2 matrix, the transfer matrix from substrate to top

class
OptStrata.
OptStrata
(wl=3.0, materials=['Air', 'InP'], moleFracs=[0.0, 0.0], dopings=[0.0, 0.0], Ls=[1.0, 1.0], mobilities=None, cstmIndx={}, cstmPrd={}, cstmGain={})¶ Class for groups of stratum, a wrapper of
MaxwellLayer
with material parsing support Parameters
wl (float) – Wavelength in vacuum to guide in the stratum
materials (list(str)) – Name of the material for each strata, with materials[0] being the top (usually air) and materials[1] the substrate.
moleFracs (list(float)) – Mole fractions for each material. The number should be between 0 and 1. For strata that the parameter is not applicable, the number doesn’t influence the result.
dopings (list(float)) – The doping level in unit 1E17 cm^3 for the material. For strata that the parameter is not applicable, the number doesn’t influence the result.
Ls (list(float)) – Thickness of stratum, same unit as wl. The first and last elements are for top and substrate and is not used for calculation
mobilities (None or list(float)) – Mobility influence the relaxation rate for plasmon resonance. When it’s None, it is assumed to have 1E13 s^1 relaxation.
cstmIdx (dict) – A dictionary of customized material, with key the name and value the complex refractive index
cstmPrd (dict) – A dictionary of customized material, with key the name and value a list of two elements, 0th being the period length (float in unit Angstrom) and 1st (int) being the nubmer of periods. If the 0th value is 0 or not key not exists, it’s not a peirodic structure. The variable is only for book keeping and is not used to validate Ls within the class
cstmGain (dict) – A dictionary of customized material, with key the name and value the gain coefficient. The variable is only for book keeping and is not used for any calculation.

confinementy
(beta, xs=None, Ey=None)¶ Return the confinement factor corresponds to mode with effective refractive index beta. If xs and Ey is None, they will be generated. The active region is labelled by anyting start with “Active”.

delete
(row)¶ Delete the strata indexed with row (top air and bottom substrate included)

indexOf
(n)¶ Return the refractive of the strata indexed with n (top air and bottom substrate included). The result is a combination of linear interpolation of mole fraction and plasmonic loss by Drude model

insert
(row, material=None, moleFrac=None, doping=None, L=None, mobility=None)¶ Insert a strata indexed with row (top air and bottom substrate included) with parameters listed

populateMtrl
(xs, mtrlList=None)¶ Populate a boolean array for index slicing on xs for material in the mtrlList. If mtrlList is None, the active region is labelled by anyting start with “Active”.

updateIndices
()¶ Update indices information according to material info
 Yields
indices (list(complex)) – complex refractive index of the stratum
index0 (complex) – Refractive index of the top (before Ls[0]) strata
indexs (complex) – refractive index of the substrate (after Ls[1])
Example¶
Todo
Add examples