Learning Forum

[leuenberger]

1. Question: I would like to add the nonlinear optical conductivity to the material graphene. Is this possible to define the nonlinear coefficients of the optical conductivity in Lumerical FDTD?
2. Question: In your example fourwave.lsf, how is it possible to calculate the conversion efficiency in terms of input and output powers between an input field and an output field at two different frequencies?

[Guilin Sun]

A1: unfortunately, all current nonlinear material models are for refractive index or permittivity. I would suggest you to file a feature request: Vote new features, and file your feature request
A2: it does not normalize the power with the input source. Details can be found in the description of the example.

[Guanhui Wang]

Hi gsun
In represent of the customer, here is his further comments:
Is there a way to manually add the nonlinear optical conductivity to the material graphene? Or is it possible to define a new 2D material with nonlinear optical coefficients?
Is there a way to calculate the conversion efficiency in terms of the input and output powers at two different frequencies? Is there a script for that?

[Guilin Sun]

A1: currently both of the methods do not work. Please file a feature request. Vote new features, and file your feature request

A2: if you mean the conversion efficiency is power(f2)/power(f1) where f1 is the fundamental frequency and f2 is the nonlinear frequency, yes you can, with "no norm". You may also use "Transmission" (with normalization on) for an estimation since the sourcepower(f2) might not be accurate from the source spectrum, as it is extremely small compared to sourcepower(f1).