Continuous wave operation of quantum cascade lasers is reported up to a temperature of 312 kelvin. The devices were fabricated as buried heterostructure lasers with high-reflection coatings on both laser facets, resulting in continuous wave operation with optical output power ranging from 17 milliwatts at 292 kelvin to 3 milliwatts at 312 kelvin, at an emission wavelength of 9.1 micrometers. Th...

The hydrogen atom is an important testing ground for fundamental theories. High resolution laser spectroscopy has provided cornerstones such as the measurement of fundamental constants, a test of quantum electrodynamics, and even the investigation of hadronic structure [1]. The recent production of antihydrogen atoms [2], albeit at almost the speed of light, has given prospect of a new field. P...

Channel waveguides based on a polymer, 6fluorinated-dianhydride/epoxy, which is actively doped with a rare-earth-ion-doped complex, Nd(thenoyltrifluoroacetone)3 1,10-phenanthroline, have been fabricated. Photoluminescence peaks at 880 nm, 1060 nm, and 1330 nm have been experimentally observed. By optimization of the fabrication procedure of both, host material and optical structure, continuous-...

In optical modulation, the highest available modulation rate is basically limited to the GHz frequency range at best. This is because optical modulation is often performed using electro-optic or acousto-optic effects that require application of an external signal to solid-state nonlinear optical materials. Here we describe optical modulation of continuous-wave radiation at frequencies exceeding...

Using the technique of terahertz photomixing, a continuous-wave terahertz source is used to characterise various semiconductors in the frequency range from 0.06 to 1.0 THz. By directly analysing the interference pattern of the transmission through semiconductor wafers using Fabry-Pérot theory, information regarding the carrier concentration, sample thickness and refractive index is obtained wit...

optimization of reservoir parameters is an important issue in petroleum exploration and production. the ant colony optimization(aco) is a recent approach to solve discrete and continuous optimization problems. in this paper, the ant colony optimization is usedas an intelligent tool to estimate reservoir rock properties. the methodology is illustrated by using a case study on shear wave velocity...

The response of hypersonic boundary layer over a blunt wedge to freestream pulse acoustic disturbance was investigated. The stability characteristics of boundary layer for freestream pulse wave and continuous wave were analyzed comparatively. Results show that freestream pulse disturbance changes the thermal conductivity characteristics of boundary layer. For pulse wave, the number of main dist...

A prototype continuous wave MRI system operating at 7T has been used successfully to study a variety of heterogeneous materials exhibiting T2 relaxation values ranging from 10 micros to 50 ms. Two-dimensional images of a poly(methly methacrylate) (PMMA) resolution phantom (T2=38 micros) exhibited a spatial resolution of approximately 1mm at a magnetic field gradient strength of 200 mT/m. The te...

We describe continuous-wave mode locking and Q switching of an Er:LiYF(4) trio upconversion laser operating in the green spectral region.