Abstract: A solar collector is formed as a compound arrangement of a multiple number of tapered, pyramidal-type structures. This forms an N-stage solar collector, each stage providing a degree of concentration and thus forming an arrangement that is smaller than a single stage collector (while achieving the same amplification factor). The stages are arranged in tandem along a common optical axis, with the output of the first stage becoming the input for the second stage, and so on. It was found that a reduced number of reflections is required, reducing the loss of the overall system.

Abstract: A solar collector utilizes multiple reflections of light passing down a tapered, pyramidal-type structure made of highly-reflective mirrored surfaces. A right-angled truncated reflective pyramidal structures have been discovered to have many properties which make them superior to existing concentrator geometries. The use of a tapered, pyramidal-type structure creates multiple reflections which appear at the collector output in the form of a Buckminster-Fullerene display, providing improved collector efficiency and amplification when compared to prior art “concentrators” of the Fresnel lens or parabola type.

Abstract: A solar collector is formed as a compound arrangement of a multiple number of tapered, pyramidal-type structures. This forms an N-stage solar collector, each stage providing a degree of concentration and thus forming an arrangement that is smaller than a single stage collector (while achieving the same amplification factor). The stages are arranged in tandem along a common optical axis, with the output of the first stage becoming the input for the second stage, and so on. It was found that a reduced number of reflections is required, reducing the loss of the overall system.

Abstract: A solar collector utilizes multiple reflections of light passing down a tapered, pyramidal-type structure made of highly-reflective mirrored surfaces. A right-angled truncated reflective pyramidal structures have been discovered to have many properties which make them superior to existing concentrator geometries. The use of a tapered, pyramidal-type structure creates multiple reflections which appear at the collector output in the form of a Buckminster-Fullerene display, providing improved collector efficiency and amplification when compared to prior art “concentrators” of the Fresnel lens or parabola type.

Abstract: Biological particles are successfully trapped in a single-beam gradient force trap using an infrared laser. The high numerical aperture lens objective in the trap is also used for simultaneous viewing.Several modes of trapping operation are presented.

Abstract: The invention provides a method for making an optical fiber with a uniformly thin section of cladding. A preform having a core and at least one cladding layer is first made. The preform is prepared by cutting the preform so that the core is close to the surface of the preform. An optical fiber is pulled from the cut preform so the core is close to the surface of the optical fiber. The fiber may have cladding further removed by etching. A material selective etch may be used to make a protruding core fiber. Etching may be done on the preform before pulling the fiber.

Abstract: A device using a birefringent optical fiber having periodic integral perturbations with the period equal to the birefringence beat length being useful as, for example, a polarization rotator and an optical filter.

Abstract: An inline single-mode fiber attenuator (10) is disclosed which may be formed by a tandem combination of a birefringent polarization-preserving fiber (12) and a single polarization fiber (14). The birefringent fiber functions as a variable wave plate and the single polarization fiber functions as a fiber polarizer. By continuously changing the local birefringence of the birefringent fiber with, for example, tension, pressure, or temperature, the phase difference between the two polarization components of light traveling through the birefringent fiber is continuously modified. The difference in phase causes suppression of one of the polarization components as it enters the fiber polarizer and, therefore, the output of the fiber polarizer, the sum of the two polarizations, is attenuated. The attenuator may be tuned by changing the local birefringence of the birefringent fiber.

Abstract: The invention provides apparatus comprising at least two beams of coherent radiation directed so as to intersect and form a standing wave pattern having a period .LAMBDA. in an optically responsive medium. The optically responsive medium is a colloidal suspension of dielectric particles in a liquid medium, the dielectric particles and liquid having different indices of refraction, and the diameter of the particles being less than or approximately equal to the period .LAMBDA.. The dielectric particles are arranged into a grating by the electric fields carried by the beams of coherent radiation. In an embodiment of the invention, the dielectric particles are small dielectric spheres. The dielectric particles and the liquid may have approximately equal mass densities. A third beam of light may generate an output beam of light by degenerate four-wave mixing processes incorporating a dielectric grating made by the electric fields carried by the beams of coherent radiation.

Abstract: A cw laser beam of radiation superimposed upon a beam of particles, for example a beam of neutral particles, can cause substantial changes in particle trajectories when the radiation frequency is tuned near a resonant transition in the particle. The particles can be confined by, ejected from, or steered by the laser beam. The present invention teaches the range of values over which the frequency of electromagnetic radiation is to be offset from the frequency of a particle resonance, as a function of radiation power for specific wave propagation modes, to produce best focusing of the particle beam by a copropagating beam of electromagnetic radiation. Our invention takes into account the effect of random fluctuations which arise out of the quantum nature of the electromagnetic wave-particle interaction in order to determine the appropriate range of values.

Abstract: A multiposition optical switch is disclosed in which two quarter-period graded refractive index (GRIN) lenses (1 and 2) having first (1.2 and 2.1) and second (1.1 and 2.2) end surfaces are supported in a structure (33 and 34) in an axially aligned fashion with their first surfaces abutting in a substantially parallel relation which permits rotating at least one lens about the common lens axis (3 and 3.1). An input fiber (10) is affixed to the second surface (1.1) of one GRIN lens at a predetermined radial offset to the common lens axis; and a multiplicity of output fibers (11-16) are affixed to the second surface (2.2) of the other lens at the same predetermined radial offset, but at a plurality of angular displacements about the common lens axis. By rotating one lens relative to the other, light from the input fiber is selectively coupled to the output fibers.

Abstract: An improvement on an optical levitation device is disclosed for damping perturbations of the position of a particle levitated in vacuum. It combines feedback control of the supporting laser beam with adjustment of the beam shape and size in order to damp perturbations in both the vertical and horizontal directions by means of the vertical feedback damping apparatus.

Abstract: A tunable radiation source employing the stimulated Raman-scattering process is disclosed. The source generates several orders of Stokes radiation in an optical-fiber oscillator cavity, which Stokes radiation may be independently tuned by incorporating separate tuning elements for the several Stokes orders. Several different arrangements of fiber and tuning elements are disclosed.