[PDF] Top 20 Temperature Dependent High Speed Dynamics of Terahertz Quantum Cascade Lasers

... the temperature-dependent current–voltage (IV) characteristics of the QCL, shown in ...measured temperature-dependent IV data, rather than use theoretically predicted IV ... See full document

... increasing temperature, while the steady-state optical output power decreases and ceases altogether at ∼53 ...with temperature for 470 mA rectangular current pulses is shown in ...against temperature ... See full document

... sub-kilohertz quantum-noise-limited linewidths [36] and also offer potential for tunability ...TPI—namely: high source powers exceeding those of optically pumped and thermal sources by several orders of ... See full document

... surface-emitting terahertz frequency quantum cascade lasers utilising non-uniform second-order distributed feedback ...ridge-waveguide lasers of similar size, whilst maintaining similar ... See full document

... Laser diodes exploiting the coupled-cavity (CC) geome- try where two sub-cavities are separated by an air gap were first demonstrated in the 1980s as a means for achieving sin- gle mode operation, alternative to ... See full document

... Several further areas for investigation of Ag waveguides have been identified. Firstly, the higher thermal conductivity of the Ag film, compared to the Au film, can also contribute to the increase in the operating ... See full document

... Figure 3 shows the simulation output for a CC THz QCL with an active cavity length of 1.5 mm, air gap length of 13 µm, and passive cavity length of 1.582 mm. The passive cavity of the CC THz QCL was driven by a series of ... See full document

... Light-current-voltage and far-field characterization. Devices with two different groove widths were fabricated, labeled as A and B. The groove widths of device A were 600 mm, whilst device B had a wider groove width of ... See full document

... Fig. 4 shows the waveguide block with a QCL integrated inside. The wave- guide block was precision-machined directly into a Cu block by mechanical mi- crofabrication techniques, with a channel of cross-sectional ... See full document

... of temperature and threshold current, that are obtained with a metal-metal (MM) ...and high mode index also means that MM QCLs tend to have poor output powers and highly divergent ... See full document

... an electromagnetically induced transparency analogue, produced by the coupling between a bright resonator and two dark resonators. The orientation of these resonators is such that a radiating electric dipole orthogonal ... See full document

... crystal lasers 18 and edge-emitting third-order (periodic) ...highly dependent on the lasing frequency, it requires high precision, commonly a demanding ... See full document

... operating temperature, the shape of the drive pulse can be designed to increase and linearize the range of a QCL’s frequency sweep with a carefully considered combination of adiabatic and thermal ... See full document

... the high-temperature operation possible with MM waveguides, the improved beam quality and smaller beam divergence associated with the SP waveguide lend themselves well to imaging applications, as discussed ... See full document

... principle of this device is based on an electromagnetically induced transparency ana- logue, produced by the coupling between a bright resonator and two dark resonators. The orientation of these resonators is such, that ... See full document

... both high speed and high sensitivity ...fast high-resolution THz imaging system is to utilise a THz QCL as an illumination source and a microbolometer-based THz camera as a ... See full document

... The procedure schematically reproduced in Fig. 6 represents a simplified picture. In fact, because the Golay cell is sensitive only to slow frequency power differences, the fast reflectivity modulation superimposed on ... See full document

... The system at the Dirac point behaves as a p-n-n+ junction, corresponding to the Pd-graphene-Ti contacts [25-27]. This trend is well represented by the measurements acquired without a pin-hole in order to maximize the ... See full document

... Figure 7 shows the typical LIV characteristics as a function of heat sink temperature of two devices with the same dimension of 3 mm × 425 m. They were fabricated from wafers from different growth campaigns. ... See full document

... cryogenic temperature of the THz source and the leaf ...low-current, high-efficiency THz QCLs [35]: they can be operated on board of compact, self-contained Stirling cryo-coolers, that necessitate only of ... See full document