Graphene is an ideal material for highperformance photodetectors because of its superior electronic and optical properties. However, graphene's weak optical absorption limits the photoresponsivity of conventional photodetectors based on planar (two-dimensional or 2D) back-gated graphene field-effect transistors (GFETs). Here, we report a self-rolled-up method to turn 2D buried-gate GFETs into three-dimensional (3D) tubular GFETs. Because the optical field inside the tubular resonant microcavity is enhanced and the light−graphene interaction area is increased, the photoresponsivity of the resulting 3D GFETs is significantly improved. The 3D GFET photodetectors demonstrated room-temperature photodetection at ultraviolet, visible, mid-infrared, and terahertz (THz) regions, with both ultraviolet and visible photoresponsivities of more than 1 A W −1 and photoresponsivity of 0.232 A W −1 at 3.11 THz. The electrical bandwidth of these devices exceeds 1 MHz. This combination of high photoresponsivity, a broad spectral range, and high speed will lead to new opportunities for 3D graphene optoelectronic devices and systems.

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The propagation of subsonic waves supported by laser energy addition is considered. The propagation velocity is modified to account for radiation diffusion by vacuum ultraviolet photons. A simplified two-band radiation transport model is formulated.

The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.

Articles you may be interested inMeasuring fast electron spectra and laser absorption in relativistic laser-solid interactions using differential bremsstrahlung photon detectors Rev. Sci. Instrum. 84, 083505 (2013); 10.1063/1.4816332Interactions of intense ultraviolet laser radiation with solid aerosols Absorption spectra of metal oxides using optogalvanic spectroscopyThe. existence ~f metal o~idc:s at the surface of a metal irradiated by an intense laser beam leads to par.ttal a~so~tlOn o~ ~h~ incIdent radiation in the blow-off vapor due to vibration-rotation bands whICh eXIst In the vIcinIty of the laser frequency. We present calculations for the vibration-rotation bands of SIO, Fe~, AIO, and TiO in the IO.6-J.l range for application to CO 2 laser interaction. The absorptIOn .coefficl~nts are calculated by use of a just overlapping line model. The range of validity of the model IS estabhsh~ by perfonning line-by-line calculations in the vicinity of a typical laser line. The absorptl~n coeffiCIents are then supplemented with an equilibrium chemistry model for laser interactIon w.lth .Ai203 and Si?2 su~aces. These calculations may be used to establish the importance of surface shIelding for cases In which the blow-off vapor exists in the range of temperatures up to about 7000 OK.

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In this paper, we present a method of analysis by which the Maxwellianized electron cascade equations are coupled to the fluid-mechanics conservation equations for the purpose of investigating the effect of a shock-induced flow field on breakdown. A particular example of breakdown initiated behind a previously existing blast wave in argon is investigated. It is shown that the breakdown process may be hindered by the rapid hydrodynamic cooling due to geometrical expansion of the mass element under consideration.