The parabolic or forward scattering approximation to the equation describing wave propagation in a random medium leads to a stochastic partial differential equation which has the form of a random SchrOdinger equation. Existence, uniqueness and continuity of solutions to this equation are established. The resulting process is a Markov diffusion process on the unit sphere in complex Hilbert space...

We report experimental results demonstrating 54% power conversion efficiency ~43% energy conversion efficiency!, from a two-stage X-band traveling wave tube amplifier designed for high-power operation. The first stage of the amplifier is a 12-cm-long Boron Nitride dielectric section used to modulate the electron beam. The second stage consists of a long high-phase-velocity bunching section foll...

One of the major considerations in planning photoproduction experiments is the choice of technique for generating the photon beam. Several possibilities exist, chieey Compton-backscattered laser beams, tagged and untagged bremsstrahlung, and coherent bremsstrahlung from a crystal. In a coherent bremsstrahlung beam, collimation can be used to suppress the incoherent component and to narrow the e...

We find a dramatic enhancement of electron propagation along a narrow range of real-space angles from an isotropic source in a two-dimensional quantum well made from a zinc-blende semiconductor. This "electron-beam" formation is caused by the interplay between spin-orbit interaction originating from a perpendicular electric field to the quantum well and the intrinsic spin-orbit field of the zin...

To clarify the mechanism of acicular ferrite formation in low carbon submerged arc weld metals of a Ti-B system with different aluminum contents, the lattice misfit between inclusion and acicular ferrite was investigated. The inclusions were directly sliced into thin foils by a focused ion beam device and crystallographic analyses were performed using a transmission electron microscope. These i...

There is interest in frequency doubling a 1178 nm narrow linewidth fiber laser source for sodium guidestar laser applications. 1178 nm can be generated via the following methods documented in the scientific literature and patents: 1. Direct lasing of Yb doped fiber [1]; 2. Direct lasing of photonic bandgap fiber [2]; 3. Generation of 1178 nm via the Raman process [3]; and 4. Lasing of a semicon...

Adjustable narrow band holographic reflective filter with the absolute diffraction efficiency about 95% has been recorded in the volume of photo-thermo-refractive glass Attenuation up to 20 times of transmitted beam was observed. Advantages of holographic filters in inorganic glass for laser power attenuation are discussed. © 2003 Optical Society of America OCIS codes: (230.1480) Bragg reflecto...

Recently, harmonic imaging has been shown to increase image quality in medical imaging. This is believed to be caused by decreased sidelobes. It is also due to a decreased sensitivity to near-field aberrations owing to the lower transmission frequency, and the lower relative amplitude of the second harmonic in the near-field. One of the problems of limited diffraction beams has been the sidelob...

We describe and characterize alternative configurations for Doppler-free polarization spectroscopy. The suggested apparatus enables complete pump/probe beam overlap and allows substantial miniaturization. Its utility and performance for narrow linewidth, high-stability frequency locking is discussed for the /5S(1/2)F=2>-->/5P(3/2)F(')>D(2) transition in (87)Rb.

GaAs/GaAlAs heterostructure lasers with a monolithic confocal unstable resonator were demonstrated. The curved mirrors satisfying the confocal condition were fabricated by etching. Close to threshold, the lasers operate in a single lateral mode with a nearly collimated output beam. A single-lobe far-field intensity distribution as narrow as 1.9 degrees full width at half maximum was measured.