Functions

General functions

SpinWaveToolkit.distBE(w, temp=300, mu=-6.626070145940079e-22)

Returns Bose-Einstein distribution for given chemical potential and temperature.

Parameters:

wfloat

(rad Hz) angular frequency.

tempfloat

11. temperature.

mufloat

10. chemical potential.

Returns:

BEdistfloat or ndarray

Bose-Einstein distribution in dependance to frequency.

SpinWaveToolkit.wavenumber2wavelength(wavenumber)

Convert wavelength to wavenumber. lambda = 2*pi/k

Parameters:

wavenumberfloat or array_like

(rad/m) wavenumber of the wave.

Returns:

wavelengthfloat or ndarray

13. corresponding wavelength.

See also

wavelength2wavenumber

SpinWaveToolkit.wavelength2wavenumber(wavelength)

Convert wavenumber to wavelength. k = 2*pi/lambda

Parameters:

wavelengthfloat or array_like

13. wavelength of the wave.

Returns:

wavenumberfloat or ndarray

(rad/m) wavenumber of the corresponding wavelength.

See also

wavenumber2wavelength

SpinWaveToolkit.wrapAngle(angle)

Wrap angle in radians to range [0, 2*np.pi).

Parameters:

anglefloat or array_like

(rad) angle to wrap.

Returns:

wrapped_anglefloat or ndarray

(rad) angle wrapped to [0, 2*np.pi).

SpinWaveToolkit.roots(f, a, b, dx=0.001, eps=1e-09, args=())

Find all roots of a continuous function f(x, *args) within a given interval [a, b].

Detects all roots spaced at least by dx with a precision given by eps.

For optimal performance, normalize dx and eps to the scale of your input. In case it didn’t find all expected roots, try decreasing dx, but note that it can extend the calculation time significantly.

Parameters:

fcallable()

Function to evaluate with signature f(x, *args).

a, bfloat

(x units) left and right boundaries of the interval to search.

dxfloat

(x units) stepsize of evaluation points (coarse search).

epsfloat, optional

(x units) tolerance of the to-be-found roots (fine search).

argslist, optional

List of arguments to be passed to f.

Returns:

xslist[float]

(x units) list of all found roots.

See also

bisect, rootsearch

BLS related functions

SpinWaveToolkit.fresnel_coefficients(lambda_, DF, PM, d, source_layer_index, output_layer_index)

Compute Fresnel coefficients for p- and s-polarized waves as a function of lateral wavevector q.

Parameters:

lambda_float

13. wavelength of the calculated light.

DFarray_like

() array of dielectric functions (complex) for each layer, ordered from top (superstrate) downward.

PMarray_like

() array of relative permeabilities for each layer (typically ones).

darray_like

(m) array of thicknesses for the layers between the superstrate and substrate. Length should be len(DF) - 2.

source_layer_indexint

0-indexed index of the layer where the source (induced polarization) is located.

output_layer_indexint

0-indexed index of the layer where the output is desired.

Returns:

htpfunction

A function that computes the p-polarized Fresnel transmission coefficients for given q.

htsfunction

A function that computes the s-polarized Fresnel transmission coefficients for given q.

SpinWaveToolkit.sph_green_function(Kx, Ky, DFMagLayer, wavelength, tp, ts)

Compute the spherical Green’s functions for p- and s-polarized fields.

Parameters:

Kx, Kyndarray

(rad/m) lateral wavevector components.

DFMagLayerfloat

() dielectric function (permitivity) of the magnetic layer.

wavelengthfloat

13. wavelength of the light.

tp, tslist or array_like

Fresnel coefficients for p- and s-polarization, respectively. Each is expected to have two elements (e.g. tp[0] and tp[1]).

Returns:

pGFlist[list]

A 3×2 list containing the p-polarized Green’s function components.

sGFlist[list]

A 3×2 list containing the s-polarized Green’s function components.

SpinWaveToolkit.getBLSsignal(SweepBloch, KxKyBloch, Bloch, Exy, E, DF, PM, d, NA, Nq=30, source_layer_index=1, output_layer_index=0, wavelength=5.32e-07, collectionSpot=1e-06, focalLength=0.001)

Calculate the BLS signal from the Bloch functions.

Parameters:

SweepBlochndarray

Sweep vector of the Bloch functions. Usually frequency of spin waves.

KxKyBlochtuple[ndarray]

(rad/m) tuple containing the 1D grids (kx_grid, ky_grid) on which the Bloch functions are defined.

Blochndarray

Array with shape (3, Nf, Nkx, Nky) containing the Bloch function components (Mx, My, Mz) for each frequency and KxKy grid point.

Exyndarray

(m) XY grid for the electric field. 2D array with shape (Ny, Nx) containing the X and Y coordinates of the electric field.

Endarray

(V/m) 3D array with shape (3, Ny, Nx) containing the X, Y, Z components of the electric field.

DFndarray

() vector of the complex dielectric functions for each material in the stack.

PMndarray

() vector of the complex permeability functions for each material in the stack.

dndarray

(m) thickness of all layers in the stack excluding the superstrate and substrate. Usually just the thickness of the magnetic layer.

NAfloat

Numerical aperture of the optical system.

Nqint, optional

Number of points in the q-space grid. Default is 30.

source_layer_indexint, optional

Index of the source layer in the stack. Default is 1.

output_layer_indexint, optional

Index of the output layer in the stack. Default is 0.

wavelengthfloat, optional

13. wavelength of the light. Default is 532e-9.

collectionSpotfloat, optional

(m) collection spot size - used here as the beam waist. Default is 1e-6.

focalLengthfloat, optional

13. focal length of the lens. Default is 1e-3.

Returns:

ExSndarray

(V/m) scattered electric field in the X axis. 1D array with shape (Nf,) containing the scattered electric field in the X direction for each frequency in SweepBloch.

EySndarray

(V/m) scattered electric field in the Y axis. 1D array with shape (Nf,) containing the scattered electric field in the Y direction for each frequency in SweepBloch.