E.i. Dupont De Nemours and Company

Cornell University

Other

Lap K Cheng

Chung L Tang

Albert A Ballman

Lap-Tak Andrew Cheng

Peter E Powers

Walter R Bosenberg

Daniel C Edelstein

John D Bierlein

Wayne S Pelouch

Randall J Ellingson

Elliot S Wachman

A photosensitive printing element comprising a support; and a photopolymerizable layer comprising a photopolymerizable composition comprising at least one elastomeric binder, at least one monomer, an initiator having sensitivity to actinic radiation, and at least one photobleachable compound having sensitivity to actinic radiation; is described. Preferred photobleachable compounds are unsubstituted or substituted naphthylvinyl pyridines; unsubstituted or substituted styrylquinolines; diphenyl maleic anhydride; isomers of any of the foregoing; derivatives of any of the foregoing; and any combination of the foregoing. Such photosensitive printing elements are used to prepare flexographic printing plates and are useful in enhancing resolution and differentiating image areas from non-image areas in images produced therefrom by reducing the deleterious effect of scattered light.

Photobleachable compounds for use in flexographic printing plates

A broadly tunable femtosecond optical parametric generator includes a cavity having a pumping section in which is located a nonlinear crystal selected from the group CTA and RTA, cut for noncritical phasematching. The plane of the optical x axis and or the optical y axis of the crystal is aligned with the axis of the pumping section. A Ti:S laser pumping beam is directed into the pumping section either collinearly or noncollinearly with the pumping section axis and impinges on the crystal to produce signal and idler beams. The laser is tunable to produce OPO output beams between about 1 and 4 .mu.m.

Tunable optical parametric oscillator

A hydrothermal process is disclosed for growing a crystal at MTiOXO.sub.4 wherein M is NH.sub.4, K, Rb and/or Tl or mixtures thereof with Cs and X is P and/or As, at elevated temperatures using a mineralizer comprising both M.sup.+1 and X.sup.+5 and an amount of F.sup.-0 effective to increase the solubility of MTiOXO.sub.4 in the mineralizer. Mineralizers containing F.sup.-1, M.sup.+1 and X.sup.+5 are disclosed wherein F.sup.-1 is present in an amount effective to increase the solubility of MTiOXO.sub.4 in the mineralizer and to provide a MTiOXO.sub.4 solubility of at least about 1% by weight at the operating temperature and pressure for the hydrothermal production.

Hydrothermal aqueous mineralizer for growing optical-quality single

Doped crystalline compositions (e.g., single domain crystals) of MTiOAsO.sub.4 (wherein M is K, Rb and/or Cs) are disclosed which contain at least about 10 ppm total of Fe, Sc and/or In dopant. Also disclosed is a flux process which is characterized by adding said dopant to a melt containing the components for forming MTiOAsO.sub.4, in an amount effective to provide a doped single domain crystal of MTiOAsO.sub.4 containing at least 10 ppm of said dopant.

Doped crystalline titanyl arsenates and preparation thereof

A continuous wave tunable femtosecond optical parametric oscillator includes an oscillator cavity including a pumping cavity. A nonlinear KTiOAsO.sub.4 crystal (KTA) is located in the pumping cavity and is pumped by a Ti:sapphire laser to produce output pulses having widths as short as 85 femtoseconds at wavelengths in the range 1.0 .mu.m to 5.0 .mu.m.

Optical parametric oscillation using KTA nonlinear crystals

A flux process is disclosed for producing a single orthorhombic crystal of Cs.sub.1-x M.sub.x TiOAsO.sub.4 (where M is Na, K, Rb, and/or Tl and x is from 0 to 0.4) wherein the dimension of the crystal along each axis is at least about 2 mm, and wherein the product at the dimensions along the three axes is at least about 15 mm.sup.3. The process involves preparing a homogeneous melt containing the components for forming said crystal and a flux comprising oxides of Cs and As at a temperature no higher than the decomposition temperature of said orthorhombic crystal, the mole fraction of M relative to the total Cs+M in the melt being within the range of from 0 to about 0.2; introducing a seed crystal for said single crystal in the melt; activating the controlled crystallization on the seed crystal; and continuing the crystallization until formation of the single crystal is completed. Single crystals of Cs.sub.1-x M.sub.x TiOAsO.sub.4 (including crystals at least about 5 mm.times.5 mm 5 mm) are also disclosed.

Single cesium titanyl arsenate-type crystals, and their preparation

Method and device for wavelength conversion using type II phase matching are characterized by employing a crystal consisting essentially of doped MTiOXO.sub.4 (wherein M is K, Rb and/or Tl and X is P and/or As) containing Fe, Nb and/or Ta dopant in an amount, totalling at least about 100 ppm, effective to increase the n.sub.z -n.sub.x optical birefringence of the doped crystal at least about 0.001 compared to a crystal without the dopant. Generation of output waves of an optical birefringence higher than the highest corresponding optical birefringence of a crystal without the dopant is disclosed. Among the useful crystals are crystals consisting essentially of doped MTiOXO.sub.4 containing at least about 100 ppm Ta.

Increasing the birefringence of KTP and its isomorphs for type II phase

A hydrothermal process is disclosed for growing a crystal at MTiOXO.sub.4 wherein M is NH.sub.4, K, Rb and/or Tl or mixtures thereof with Cs and X is P and/or As, at elevated temperatures using a mineralizer comprising both M.sup.+1 and X.sup.+5 and an amount of F.sup.- effective to increase the solubility of MTiOXO.sub.4 in the mineralizer. Mineralizers containing F.sup.-1, M.sup.+1 and X.sup.+5 are disclosed wherein F.sup.-1 is present in an amount effective to increase the solubility of MTiOXO.sub.4 in the mineralizer and to provide a MTiOXO.sub.4 solubility of at least about 1% by weight at the operating temperature and pressure for the hydrothermal production.

Hydrothermal process for growing optical-quality single crystals and

The operation of a .beta.-BaB.sub.2 O.sub.4 optical parametric oscillator is disclosed. The oscillator is tunable in the visible and near infrared. For example, a .beta.-BaB.sub.2 O.sub.4 crystal 10.5.times.10.5 nm.sup.2 .times.11.5 mm, cut at .theta.=30.degree. was pumped at 354.7 mm, and was tunable through 0.45-1.68 .mu.m, with a total energy conversion efficiency of 9.4%.

Optical waveguides prepared by liquid phase epitaxy comprising a film of M.sub.1-x N.sub.x TiAs.sub.1-a P.sub.a O.sub.5 on a substrate of MTiAs.sub.1-(a+b) O.sub.5 P.sub.(a+30 b) is disclosed.

M.sub.1-x N.sub.x TiAs.sub.1-a P.sub.a O.sub.5 waveguides grown by

A laser pulse generator utilizes intracavity doubling in an ultrathin beta barium metaborate crystal to produce femtosecond pulses in the ultrashort ultraviolet wavelength range. The generator includes a colliding-pulse passively mode-locked ring dye laser which propagates a pulsed beam of primary laser light in a cavity. The primary light beam has a repetition rate of 10.sup.8 Hz and a pulse width in the femtosecond range. The crystal is located in the cavity so that the primary beam strikes one crystal surface at Brewsters angle and propagates through the crystal at its phase-matching angle. The primary beam and its second harmonic are emitted from the opposite surface, the harmonic wave having the same repetition rate and substantially the same width as the primary beam, but one-half its wavelength.

Femtosecond ultraviolet laser using ultra-thin beta barium borate

An optical parametric oscillator capable of operating in the 0.300 to 0.400 micrometer wavelength range is disclosed. The oscillator includes a cavity defined at its ends by a pair of cavity resonator mirrors. A nonlinear optical crystal is positioned on the optical axis of the cavity intermediate the mirrors and is rotatable about a crystalline axis to tune the oscillator. A pair of pump steering mirrors are mounted in the cavity, one mirror between each resonator mirror and the corresponding end of the crystal. A source of pumping energy supplies energetic light to the cavity, the pumping beam being directed into the cavity and onto a first steering mirror, thence through the crystal and to the second steering mirror which then directs the pumping beam out of the cavity. The pumping beam may be at a wavelength of 266 nm, for example, to produce an output wave from the oscillator within the range of interest.

Growing community of inventors

Bear, DE, United States of America

Lap K Cheng