IIUC, the article seems to define the term "light phase" to mean what a layman light me would call "brightness". But it seems crazy to me that they'd overload the term "phase", when it has a very obvious alternative definition in the field of optics.
Can someone clarify if that's what the article is actually saying?
Had to look up Quantitative phase-contrast microscopy:
> Conventional phase contrast microscopy and related methods, such as differential interference contrast microscopy, visualize phase shifts by transforming phase shift gradients into intensity variations.
To detect phase changes you have to turn them into amplitude changes. It then makes sense to call the phase-change-turned-amplitude-change a "phase change." Yes, this elides a critical part of the interpretation, but if we were to insist on carrying around a complete interpretation with every noun we'd wind up with nouns as long as textbooks. Even Germans don't take it that far.
Can someone clarify if that's what the article is actually saying?