Abstract: A laser source assembly (324) for generating an output beam (326) that is in the mid-infrared range includes a quantum cascade gain media (338), a first lead (340), a second lead (342), and an infrared transmissive potting material (348). The quantum cascade gain media (338) generates the output beam (326) that exits from a first facet (350) of the gain media (338). The first lead (340) and the second lead (342) are electrically connected to the quantum cascade gain media (338). The infrared transmissive potting material (348) encloses and embeds the quantum cascade gain media (338), a portion of the first lead (340), and a portion of the second lead (342). Because theses components are enclosed and retained by the potting material (348), the resulting laser source assembly (324) is stable, rugged, small, portable, easy to manufacture, reliable, and relatively inexpensive to manufacture.

Abstract: A laser source (10) for emitting an output beam (12) includes a first gain medium (16B) that generates a first beam (16A), a second gain medium (18B) that generates a second beam (18A), a common feedback assembly (28) positioned in the path of the first beam (16A) and the second beam (18), and a control system (32). The common feedback assembly (28) redirects at least a portion of the first beam (16A) back to the first gain medium (16B), and at least a portion of the second beam (18A) back to the second gain medium (18B). The control system (32) selectively and individually directs power to the first gain medium (16B) and the second gain medium (18). Additionally, the common feedback assembly (28) can include a feedback mover (46) that continuously adjusts the angle of incidence of the first beam (16A) and the second beam (18A) on the feedback assembly (28).

Abstract: A method for determining absolute number densities of particles in a solution is disclosed based on a light scattering method. A light scattering photometer is calibrated to produce the Rayleigh ratio at each angle measured with respect to light scattered per unit incident intensity, per unit volume illuminated within the field of view of each detector per steradian subtended by said detector. In order that the numbers calculated be accurate, the illuminated particles should be effectively monodisperse. From the excess Rayleigh ratios measured at a plurality of angles with respect to the incident light beam illuminating said sample particles, an effective size is calculated which, in turn, is used to calculate the differential scattered intensity at each angle. The number of particles per unit volume element is then determined from the measured excess Rayleigh ratio divided by the corresponding differential scattered intensity.