TDGL and FEM analysis

In this set of tutorials, we will cover conversion of qnngds.Device to tdgl.Device and skfem.mesh.MeshTri1 for analysis of device properties.

First, we will show how to generate a tdgl.Device

import qnngds as qg
from qnngds.analysis.tdgl import make_tdgl_device
import matplotlib.pyplot as plt

snspd = qg.devices.snspd.basic()
device = make_tdgl_device(
    device=snspd,
    coherence_length=0.005,
    london_lambda=0.35,
    thickness=0.01,
    gamma=23.8,
    layer=(1, 0),
)
fig, ax = device.draw()
plt.show()

We can use this object to do tdgl simulations, check out [the docs](https://py-tdgl.readthedocs.io/en/latest/) for more info.

Now, let’s analyze the structure with femwell/skfem to visualize the current density.

from qnngds.analysis.fem import (
    make_mesh,
    solve_laplace,
    visualize_mesh,
    visualize_current,
)

we can create a mesh as so:

mesh = make_mesh(device=snspd, layer=(1, 0), tolerance=0.01)
visualize_mesh(mesh)
plt.show()

Now, let’s analyze the current density by solving the laplace equation

result = solve_laplace(mesh)
visualize_current(result, ("1", "2"))
plt.show()