349 results about "Stigmatism" patented technology

A modular, compact and widely tunable laser system for the efficient generation of high peak and high average power ultrashort pulses. Modularity is ensured by the implementation of interchangeable amplifier components. System compactness is ensured by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers. Peak power handling capability of the fiber amplifiers is expanded by using optimized pulse shapes, as well as dispersively broadened pulses. Dispersive broadening is introduced by dispersive pulse stretching in the presence of self-phase modulation and gain, resulting in the formation of high-power parabolic pulses. In addition, dispersive broadening is also introduced by simple fiber delay lines or chirped fiber gratings, resulting in a further increase of the energy handling ability of the fiber amplifiers. The phase of the pulses in the dispersive delay line is controlled to quartic order by the use of fibers with varying amounts of waveguide dispersion or by controlling the chirp of the fiber gratings. After amplification, the dispersively stretched pulses can be re-compressed to nearly their bandwidth limit by the implementation of another set of dispersive delay lines. To ensure a wide tunability of the whole system, Raman-shifting of the compact sources of ultrashort pulses in conjunction with frequency-conversion in nonlinear optical crystals can be implemented, or an Anti-Stokes fiber in conjunction with fiber amplifiers and Raman-shifters are used. A particularly compact implementation of the whole system uses fiber oscillators in conjunction with fiber amplifiers. Additionally, long, distributed, positive dispersion optical amplifiers are used to improve transmission characteristics of an optical communication system. Finally, an optical communication system utilizes a Raman amplifier fiber pumped by a train of Raman-shifted, wavelength-tunable pump pulses, to thereby amplify an optical signal which counterpropogates within the Raman amplifier fiber with respect to the pump pulses.

A multi-spectrum, multi-channel imaging spectrometer includes two or more input slits or other light input devices, one for each of two or more input channels. The input slits are vertically and horizontally displaced, with respect to each other. The vertical displacements cause spectra from the two channels to be vertically displaced, with respect to each other, on a single image sensor on a stationary image plane. The horizontal displacements cause incident light beams from the respective input channels to strike a convex grating at different respective incidence angles and produce separate spectra having different respective spectral ranges. A retroflective spectrometer includes a convex grating that, by diffraction, disperses wavelengths of light at different angles and orders approximately back along an incident light beam. A single concave mirror reflects both the input channel and the dispersed spectrum. A prism, set of mirrors, beam splitters or other optical element(s) folds the input channel(s) of a spectrometer to enable the input(s) to be moved away from the plane of the image sensor, thereby enabling a large camera or other device to be attached to the spectrometer without blocking the input(s). A mounting mechanism enables a curved optical element to be adjusted through lateral and transverse translations, without requiring a gimbal mount.

Methods and devices are described that are needed to design and fabricate modified surfaces on contact lenses or on corneal tissue that correct the eye's optical aberrations beyond defocus and astigmatism. The invention provides the means for: 1) measuring the eye's optical aberrations either with or without a contact lens in place on the cornea, 2) performing a mathematical analysis on the eye's optical aberrations in order to design a modified surface shape for the original contact lens or cornea that will correct the optical aberrations, 3) fabricating the aberration-correcting surface on a contact lens by diamond point turning, three dimensional contour cutting, laser ablation, thermal molding, photolithography, thin film deposition, or surface chemistry alteration, and 4) fabricating the aberration-correcting surface on a cornea by laser ablation.

A device to compensate for asymmetrical aberrations in a beam of light includes at least one dual compensator positioned on the beam path. Structurally, the dual compensator includes two juxtaposed plates, each having a same pattern presented thereon. The patterns, however, are rotated through an angle α relative to each other. Together, the plates of the dual compensator can then be rotated on the beam path through an angle β to compensate for asymmetrical aberrations in the light beam. Dual compensators, having appropriate patterns, can be collectively used to compensate for astigmatism, coma and trefoil.