Ultrafast graphene-based broadband THz detector

Abstract

We present an ultrafast graphene-based detector, working in the THz range at room temperature. A logarithmic-periodic antenna is coupled to a graphene flake that is produced by exfoliation on SiO2. The detector was characterized with the free-electron laser FELBE for wavelengths from 8 um to 220 um. The detector rise time is 50 ps in the wavelength range from 30 um to 220 um. Autocorrelation measurements exploiting the nonlinear photocurrent response at high intensities reveal an intrinsic response time below 10 ps. This detector has a high potential for characterizing temporal overlaps, e. g. in two-color pump-probe experiments

Antenna Enhanced Graphene THz Emitter and Detector

“…In particular, it enables broadband interaction of photons with the two dimensional (2D) atomic layer from the far infrared up to the ultraviolet 3 . This has led to various optoelectronic devices operating with photons in the visible [4][5][6][7] , near infra-red [8][9][10][11] , mid infra-red [12][13][14][15][16] and far infrared [17][18][19][20][21][22][23][24] . Applications of graphene field effect transistors (GFET) in the few terahertz (THz) frequency range are particularly appealing since it's one of the least developed regimes lying in the gap between efficient manipulation with electronics and photonics [25][26][27] .…”

Picosecond dynamics of a silicon donor based terahertz detector device

“…There is a wide range of THz detectors 1 that are sensitive, have a fast response or are easy to produce, but usually not all at once (see Table I). Pyroelectric detectors 2,3 and bolometric/thermal 4-6 detection have a high sensitivity but are relatively slow, while graphene [7][8][9] and photon drag detectors 10 are fast but relatively insensitive. Doped germanium 11 and superconductor-insulator-superconductor (SIS) detectors 12 are very sensitive and have a quick response time; however, they are expensive and difficult to produce.…”

“…33 The responsivity is better than for most broadband detectors. 9 The NEP is larger than a range of other cryogenically cooled detectors, and this could be further improved with better control of the temperature and optimization of the doping density to manipulate the rates of ionization and recombination. Taking the NEP together with the high response speeds and the possibility of frequency tuning, 25 silicon FET devices such as these are strong candidates for cost effective integrated THz detection applications, due to the standard industrial processing.…”

Ultrafast Broadband Photodetectors Based on Three-Dimensional Dirac Semimetal Cd3As2

“…On the other hand, 3D Dirac semimetals possess all advantages of 2D Dirac semimetals as photosensitive materials, which is inherent from the gapless linear dispersion of massless Dirac Fermions: extermely high mobility 9 and ultrafast transient time 15 for high speed response approaching terahertz operation speed 4,16 ; gapless bandstructure for chanlleging low energy photon detection 17 down to THz frequency [18][19][20] and efficient carrier multiplications to enhance the internal quantum efficiency 21,22 . Consequently, the emergency of stable 3D Dirac semimetal Cd3As2 provides outstanding opportunity as new class of material platform for optoelectronics.…”

“…We note the photon energy range is limited by the available light source rather than response of the device itself. As a zero gap Dirac semimetal with ultrahigh mobility, Cd3As2 should possess ultra-broadband response extendable to much lower photon energy 37 down to THz similar to that of graphene [18][19][20] . Wavelength dependent SPCM measurements (Fig.…”