The sensor may be narrowband enough that part of your measured function is just whatever slice of the blackbody radiation curve it's seeing. If you factor that out, you might be back to mostly linear.

For a computable field F, the splitting set S is the set of polynomials p(X) ∈ F[X] which factor over F, and the root set R is the set of polynomials with roots in F. Work by Frohlich and Shepherdson ...

Polynomial and special function theory remains a vibrant area of mathematical research, interweaving classical algebra with advanced analysis. At its core, the study concerns algebraic expressions ...