Material Thermal Specification

tidy3d.FluidSpec	Fluid medium.
tidy3d.SolidSpec	Solid medium.

Thermal Perturbation Specification

tidy3d.LinearHeatPerturbation	Specifies parameter's perturbation due to thermal effects as a linear function of temperature.
tidy3d.CustomHeatPerturbation	Specifies parameter's perturbation due to thermal effects as a custom function of temperature defined as an array of perturbation values at sample temperature points.