Second-order NLTMM

Main class

class NonlinearTMM.SecondOrderNLTMM(mode)

Bases: object

This class calculates second-order nonlinear processes (e.g. sum-frequency, difference-frequency generation and SPDC) in layered structures. Relies on the functionality of the NonlinearTMM class.

Parameters:

modestr {‘sfg’, ‘dfg’, ‘spdc’}

Attributes:

P1NonlinearTMM

The instance of the first pump wave TMM.

P2NonlinearTMM

The instance of the second pump wave TMM.

GenNonlinearTMM

The instance of the generated wave TMM.

deltaWlSpdcfloat

The spectral collection window (in nanometers) of the SPDC signal. Only used if mode is set to "spdc". Default: NaN.

solidAngleSpdcfloat

The collection solid angle (srad) of the detector (given in vacuum). Only used if mode is set to "spdc". Default: NaN.

deltaThetaSpdcfloat

The horizontal collection window (rad) of the detector (given in vacuum). It is used to calculate the vertical span of the detector. Only used if mode is set to "spdc". Default: NaN.

AddLayer(d, material)

Adds layer to SecondOrderNLTMM. Equivalent of adding layer to P1, P2 and Gen.

Parameters:

dfloat

layer thickness (m)

materialMaterial

The class containing the material parameters.

GetIntensities()

Returns the intensities and amplitudes of incident, reflected and transmitted wave for P1, P2 and Gen. The structure must be solved first.

Returns:

_SecondOrderNLIntensities

Helper class to hold intensity data.

SetParams(**kwargs)

Helper method to set the values of all the attributes. See the docstring of SecondOrderNLTMM.

Solve()

Solves the structure.

Sweep(paramStr, valuesP1, valuesP2, layerNr=0, layerZ=0.0, outPwr=True, outAbs=False, outEnh=False, outP1=True, outP2=True, outGen=True)

Solves the structure for a series of valuesP1 and valuesP2 of param paramStr. Using this function is more convenient and faster than just changing params and solving the structure (parallelized with OpenMP).

Parameters:

paramStrstr

‘wl’:

Wavelength in meters

‘beta’:

normalized tangential wavevector

‘I0’:

intensity of the wave

‘d_i’:

thickness of layer i (0..N-1)

valuesP1ndarray of floats

Corresponding values of param paramStr for P1.

valuesP2ndarray of floats

Corresponding values of param paramStr for P2.

layerNrint

Specifies layer, where electrical field enhancement is calculated.

layerZdouble

Specifies z-coordinate of enhancement calculation inside layerNr.

outPwrbool

Turns calculation of intensities on/off.

outAbsbool

Turns calculation of absorption in the entire structure on/off.

outEnhbool

Turns calculation of enhancement in layer layerNr at distance layerZ on/off.

outP1bool

Turns calculation of P1 on/off.

outP2bool

Turns calculation of P2 on/off.

outGenbool

Turns calculation of Gen on/off.

Returns:

_SweepResultSecondOrderNLTMM

Helper class to store the result.

UpdateGenParams()

Forces the update of the wavelength and beta of the generated beam Gen.

WaveGetFields2D(zs, xs, dirStr='total')

Calculates 2D electric and magnetic fields of the beam propagating in the structure. Analogous to GetFields2D of plane waves. Only for the calculation of the generated beam fields. For pump beams use the same method of NonlinearTMM.

Parameters:

zsndarray of floats

Points on z-axis where to calculate the fields. The beginning of the first layer is at z = 0.

xsndarray of floats

Points on x-axis where to calculate the fields.

dirStr{‘total’, ‘forward’, ‘backward’}

Specifies the components of the output fields.

Returns:

_FieldsZX

Helper class to store electric and magnetic fields in regular grid.

WaveGetPowerFlows(layerNr, x0=float('nan'), x1=float('nan'), z=0.0)

Analogous to GetIntensities, but calculates the powers of the beams instead of the intensities of the plane waves. Only for the calculation of the power of the generated beam. For pump beams use the same method of NonlinearTMM.

Parameters:

layerNrint

Specifies layer number where to calculate the power of the beam.

x0float

Specifies the starting point of the integration of the power in the x-direction. By default this parameter is selected by the _Wave class.

x1float

Specifies the end point of the integration of the power in the x-direction. By default this parameter is selected by the _Wave class.

zfloat

Specifies the z-position of the line through which the integration of the power of the beam is done.

Returns:

tuple of floats (PB, PF)

PB is the power propagated into negative infinity and PF denotes the power propagating in the positive direction of z-axis.

WaveSweep(paramStr, valuesP1, valuesP2, layerNr=0, layerZ=0.0, outPwr=True, outR=False, outT=False, outEnh=False, outP1=True, outP2=True, outGen=True)

Solves the structure for waves for a series of valuesP1 and valuesP2 of param paramStr. Using this function is more convenient and faster than just changing the params and solving the structure. Analogous to Sweep.

Parameters:

paramStrstr

‘wl’:

Wavelength in meters

‘beta’:

normalized tangential wavevector

‘I0’:

intensity of the wave

‘d_i’:

thickness of layer i (0..N-1)

‘w0’:

waist size of the input beam

valuesP1ndarray of floats

Corresponding values of param paramStr for P1.

valuesP2ndarray of floats

Corresponding values of param paramStr for P2.

layerNrint

Specifies layer, where electrical field enhancement is calculated.

layerZdouble

Specifies z-coordinate of enhancement calculation inside layerNr.

outPwrbool

Turns calculation of all powers on/off.

outRbool

Turns calculation of reflected power on/off.

outTbool

Turns calculation of transmitted power on/off.

outEnhbool

Turns calculation of enhancement in layer layerNr at distance layerZ on/off.

outP1bool

Turns calculation of P1 on/off.

outP2bool

Turns calculation of P2 on/off.

outGenbool

Turns calculation of Gen on/off.

Returns:

_WaveSweepResultSecondOrderNLTMM

Helper class to store the result.

Helper classes

class NonlinearTMM._WaveSweepResultSecondOrderNLTMM

Bases: object

Helper class for SecondOrderNLTMM. Stores the results of WaveSweep method.

Attributes:

P1_WaveSweepResultNonlinearTMM

The sweep result of the first input beam.

P2_WaveSweepResultNonlinearTMM

The sweep result of the second input beam.

Gen_WaveSweepResultNonlinearTMM

The sweep result of the generated beam.

wlsGenndarray of floats

Stores the wavelength of the generated wave.

betasGenndarray of floats

Stores the normalized tangential wave vector of the generated wave.

class NonlinearTMM._SweepResultSecondOrderNLTMM

Bases: object

Helper class for SecondOrderNLTMM. Stores the results of Sweep method.

Attributes:

P1_SweepResultNonlinearTMM

Sweep results for the first input wave.

P2_SweepResultNonlinearTMM

Sweep results for the second input wave.

Gen_SweepResultNonlinearTMM

Sweep results for the generated wave.

wlsGenndarray of floats

Stores the wavelength of the generated wave.

betasGenndarray of floats

Stores the normalized tangential wave vector of the generated wave.

class NonlinearTMM._SecondOrderNLIntensities

Bases: object

This is a helper class for SecondOrderNLTMM. It stores the results of GetIntensities.

Attributes:

P1_Intensities

Instance of _Intensities class and holds the intensities of the first input wave.

P2_Intensities

Instance of _Intensities class and holds the intensities of the second input wave.

Gen_Intensities

Instance of _Intensities class and holds the intensities of the generated wave.