US Government As Represented by the Secretary of the Army

Maxion Technologies, Inc.

John L Bradshaw

Donald E Wortman

John D Bruno

Richard P Leavitt

Romel D Gomez

Quantum-cascade lasers are provided with an active section in which relaxation of carriers from a lower laser level is provided by three or more phonon-assisted transitions to levels within the active section whose energies are below the energy of the lower laser level. The gain region of the laser consists of alternating active and injector sections, with an injection barrier inserted between each injector section and the adjacent active section, and an exit barrier inserted between each active section and the adjacent injector section. The active section comprises a sufficient number of quantum wells separated by quantum barriers to produce the desired energy-level structure consisting of an upper laser level, a lower laser level, and at least three levels that have lower energies than the lower laser level, with the separation of adjacent energy levels below and including the lower laser level that are at least equal to the energy of the quantum well material's longitudinal optical phonon.

Multiple phonon resonance quantum cascade lasers

A method for improving images of surface features of a sample, constructed by a scanning probe microscope, includes constructing images of surface features of a sample with a scanning probe microscope; measuring a displacement of the sample that occurs during the constructing step; and correcting the images using the measured displacement. An apparatus for improving images of surface features of a sample, constructed by a scanning probe microscope, includes a vacuum chamber; a sample holder disposed in the vacuum chamber; at least one spring connected between the vacuum chamber and the sample holder; at least one magnet disposed in the vacuum chamber for damping vibrations of the sample holder; a probe and piezo tube assembly disposed in the vacuum chamber for scanning surface features of a sample; and an interferometer disposed in the vacuum chamber wherein the interferometer measures a distance between the sample and a point fixed with respect to the sample.

Growing community of inventors

Elkridge, MD, United States of America

John L Bradshaw