Understanding AC and Optical Conductivity: Conflicting Information Clarified

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DeathbyGreen
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Maybe someone can help me out; I've been seeing conflicting information on the meaning behind optical conductivity vs AC conductivity. Some papers seem to post plots of transmission and reflectivity, and others a Drude-like [itex]\sigma(\omega)[/itex]. In many textbooks I can't seem to find a satisfactory answer.

If we start with a system under a field [itex]E(t) = Ee^{i\omega t}[/itex], solve the Drude model to get [itex]\sigma(\omega)[/itex], is this an expression for optical conductivity or AC? And what are the geometries of both?
 
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DeathbyGreen said:
If we start with a system under a field [itex]E(t) = Ee^{i\omega t}[/itex], solve the Drude model to get [itex]\sigma(\omega)[/itex], is this an expression for optical conductivity or AC? And what are the geometries of both?
I think this depends on frequency (radio- vs. optical).
 
By optical conductivity, do you mean photo-conductivity, which is a material becoming conducting when exposed to light, or do you just mean conductivity at very high frequencies?
 
I mean conductivity induced by irradiation; I've seen this called both optical and AC conductivity. Maybe it's just called AC because the light has a frequency and an analogy can be drawn between that and actual AC electricity with connected leads?