The nonlinear ~third to fourth order! as well as linear photoconductivity in a Gallium nitride/ Indium-Gallium nitride ~GaN/InGaN! heterostructure is investigated using femtosecond pulses in the infrared ~IR! and near ultraviolet ~UV!. An anomalous IR photoresponse is explained by a four level model for the GaN region including defect density fluctuations and nonlinear carrier transport phenome...

The effects of solid-state electron injection on the peak amplitude and decay time of photosignal in a ZnO-based homojunction UV photodiode were studied using temporal photoresponse measurements under femtosecond pulses of 355 nm radiation. The injection of about 50 C of charge, carried out by applying forward bias to the junction, resulted in a nearly twofold increase of the peak photoresponse...

We report on the intrinsic optoelectronic response of high-quality dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation (of wavelength 850 nanometers) at the p-n interface leads to striking six-fold photovoltage patterns as a function of bottom- and top-gate voltages. These patterns, together with the measured spatial and density dependence of the photoresponse...

The strong coupling regime is observed in a system of two-dimensional electrons whose cyclotron motion is coupled to an electromagnetic mode in a Fabry-Perot cavity resonator. Rabi splitting of eigenfrequencies of the coupled motion is observed both in the cavity reflection spectrum and ac current of the electrons, the latter probed by measuring their bolometric photoresponse. Despite the fact ...

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Two-dimensional black phosphorus is a new material that has gained widespread interest as an active material for optoelectronic applications. It features high carrier mobility that allows for efficient free-carrier absorption of terahertz radiation, even though the photon energy is far below the bandgap energy. Here we present an efficient and ultrafast terahertz detector, based on exfoliated m...

Photoreceptor cells were enzymatically dissociated from the eye of the file clam, Lima scabra. Micrographs of solitary cells reveal a villous rhabdomeric lobe, a smooth soma, and a heavily pigmented intermediate region. Membrane voltage recordings using patch electrodes show resting potentials around -60 mV. Input resistance ranges from 300 M omega to greater than 1 G omega, while membrane capa...