Abstract: The present invention discloses an apparatus of converting gravitational energy to electrical energy. The apparatus includes a reciprocating drive mechanism for lifting liquid from a bottom reservoir to an upper reservoir and turbines between the upper and lower reservoirs which are turned by liquid falling down a flow path from the top reservoir through the turbines to the bottom reservoir. The reciprocating drive mechanism includes a large circular ring or wheel pivotally attached at its hub or center to a support frame and a cable over the upper periphery of the ring with two pipes attached one at each end of the cable. The ring pivots back and forth lifting one pipe and lowering the other pipe and vice versa. As a pipe moves down liquid enters the bottom of the pipe while liquid drains out the top of the pipe into the upper reservoir. One of the turbines is connected to the reciprocating drive mechanism and the other to a generator for producing electricity.

Abstract: The present invention provides fully tunable photonic band gap (PBG) materials. These materials are periodic composite materials comprising a high refractive index dielectric material and another optically anisotropic, birefringent, electro-optically tunable, or magneto-optically tunable material with a lower dielectric constant in which the photonic band structure can be globally or locally changed in a controlled manner by application of an external electric, magnetic, or electromagnetic field, whereby changing the refractive index properties of one or more of the dielectric constituents by application of the field modulates the photonic band structure. In one aspect of the invention, when an optically birefringent nematic liquid crystal is infiltrated into the void regions of full bandgap (PBG) material based on an inverse opal, the resulting composite material exhibits a completely tunable PBG.

Abstract: A method and circuit is disclosed for providing a control signal to a laser cavity controller. The cavity has two completely reflective surfaces. A long lived laser medium stores energy within the cavity. A computer generated waveform generated from enough values to appear substantially smooth after being amplified is provided to a control circuit having a Pockels cell or a Bragg cell. By controlling the amplitude of the computer generated waveform, the output pulse of the laser cavity is controlled.

Abstract: A multitasking optical fiber probe for collecting dosimeter information from more than one position in a sample. The basic principle of the present invention involves using one or more different sensor zones along the length of the fiber each with a different photoactive constituent having a sufficiently unique emission spectra (spectral or temporal) to enable deconvolution of the emission spectra by the computer and therefore correlation of the detected parameter with the position of the sensor zone along the length of the optical fiber. In the broadest form of the invention the probe is embodied by only one sensor zone located at some point along the length of the fiber spaced away from the end face of the fiber.

Abstract: This invention discloses optical system and method for writing a refractive index pattern in a light transmissive or light absorbing sample. A light source for providing a short pulse laser beam in the femtosecond range having a low power per unit area is coupled to provide the short pulse beam to a diffractive optical element. A curved mirror collects light transmitted through or reflected from the diffractive optical element preserves an image relating to characteristics of the diffractive optical element encoded within the collected light, and directs the collected light in wavelength independent manner while preserving the image of the diffractive optical element encoded within the collected light. A rod lens demagnifies the image within the light received from the curved mirror so as to increase its power per unit area when directed to the light transmissive or absorbing sample to be permanently impressed therein.

Abstract: The present invention provides self-collimating multiwavelength lasers (MWL) including a planar gain medium with a resonance cavity defined by superimposed gratings. These laser devices are characterized by lasing wavelengths with multiple peaks in their reflectance spectra defined by the superimposed gratings. The gratings also limit beam divergence, producing self-collimated multiwavelength output, with the potential for high power. These devices can be implemented in any planar gain medium in which multi-peak gratings can be produced, including but not limited to semiconductors and doped glasses. The self-collimated MWL's disclosed herein have applications in areas such as DWDM (dense wavelength division multiplexing) communications systems, free-space uses such as interconnects, range-finding, and inter-satellite infrared communication.