Searching for evidence of optical rectification: optically induced nonlinear photovoltage in a capacitor configuration

A current challenge in photonics is to design new versatile photodetectors based on optical-rectification-induced photovoltage; these are more attractive than classical photodetectors because they do not rely on band-to-band transitions. Identification of the origin of the photovoltage detected under intense illumination can sometimes be confusing due to the competition between several nonlinear processes. Examples of such processes are optical rectification, multiphoton absorption, and photothermal heating, all of which may result in the detection of DC photovoltage in a capacitor configuration. Herein, differences between the resulting photovoltage from these processes are analyzed and techniques are proposed to distinguish between optical-rectification-induced DC photovoltage and the photovoltage resulting from alternative effects.