USA As Represented by Secretary of the Navy

Leon Esterowitz

Roger E Allen

Melvin R Kruer

Robert C Stoneman

Filbert J Bartoli

Joseph F Pinto

Gregory J Quarles

Gregory J Kintz

Charles L Marquardt

Van O Nicolai

Arthur Linz

Hans P Jenssen

Lawrence S Goldberg

John M McMahon

Robert S Stoneman

Robert C Eckardt

James G Lynn

A dual wavelength surgical laser system for performing laser surgery on living tissue with a minimum amount of collateral tissue damage is disclosed. The dual wavelength surgical laser system comprises: a pump laser for emitting pump laser pulses of light at a preselected pump wavelength; an optical parametric oscillator responsive to each pump pulse from the pump laser for producing a first wavelength pulse of light in a water absorption band of the tissue and a second wavelength pulse of light in a protein absorption band of the tissue; a first set of optics for only passing therethrough each first wavelength pulse from the optical parametric oscillator; an optical delay line for delaying each first wavelength pulse from the first set of optics by a predetermined period of time; a second set of optics for only passing therethrough each second wavelength pulse from the optical parametric oscillator; and a beam combiner for combining each second wavelength pulse with the following delayed first wavelength pulse to form a stream of consecutive second and delayed first pulse pairs for application to the tissue.

Dual wavelength surgical laser system

A mirrorless, distributed-feedback (DFB), ultraviolet, tunable, narrow-liidth, solid state laser for remote sensing and medical applications is disclosed. Optical pumping in the DFB laser is accomplished using a frequency quadrupled, 10 Hz., Q-switched, Nd:YAG laser operating at 266 nm. The pump beam is diffracted off a grating (2400 grooves per mm.) into two parts. The two beams are subsequently recombined at the side face of the Ce:doped crystal (8 mm.times.8 mm.times.30 mm) at an angle of about 2.theta.(about 81 degrees). The resulting spatially periodic excitation within the Ce-doped gain medium due to the interferring pump beams determines the operating wavelength of the DFB laser.

Mirrorless, distributed-feedback, ultraviolet, tunable,

An ultraviolet solid state laser includes: (a) a laser cavity defined by a et of opposing mirrors, (b) a laser medium disposed in this laser cavity, where this medium includes a LiSrAIF.sub.6 (LiSAF) host material doped with enough cerium ions to produce a longitudinal mode laser emission when this laser medium is pumped; and (c) a source of pumping radiation.

Continuously tunable UV Ce:LiSAF solid state laser

A room-temperature solid state laser for producing an output laser emission t any wavelength within a preselected range of wavelengths is disclosed. In a preferred embodiment, the laser comprises: a pump laser for emitting a CW pump beam at a preselected wavelength; a laser cavity defined by a first reflective element, an output coupler reflective element and a folded mirror disposed between the first reflective element and the output coupler reflective element to form a reflective path thereamong in the laser cavity; a laser crystal disposed in the laser cavity, the laser crystal being responsive to the CW pump beam at the preselected wavelength for producing a CW laser emission within a preselected range of wavelengths when the laser crystal is pumped by the CW pump beam at the preselected wavelength, the folded mirror operating to collimate the CW laser emission in the optical path between the folded mirror and the output coupler reflective element; and a tuning element disposed in the laser cavity between the folded mirror and the output coupler reflective element for tuning the collimated CW laser emission to any wavelength within the preselected range of wavelengths.

Diode-pumped, continuously tunable, 2.3 micron CW laser

A laser apparatus, system and method include a laser crystal formed of thulium-doped yttrium-lithium-fluoride, and a laser diode arranged in proximity to the laser crystal. The laser diode is capable of emitting a first laser light which is suitable for use as a pump beam for causing lasing to occur in the laser crystal. In response to the first laser light from the laser diode, the laser crystal emits a second laser light at a wavelength which is relatively highly-absorbed by organic tissue and/or water. The second laser light is therefore well-suited to medical applications, for example, and can be used to irradiate organic tissue for medical treatment.

1.94 .mu.m laser apparatus, system and method using a thulium-doped

A tunable ytterbium-doped solid-state laser has a laser cavity defined a r of mirrors, a laser medium positioned in this cavity, means for pumping the laser medium, and means for tuning the output of this laser medium to a selected wavelength within a wavelength range. The laser medium has a host material doped with enough ytterbium ions to produce a longitudinal mode laser emission when the laser medium is pumped. In a most preferred embodiment, the laser emission is frequency-doubled and tuned to a wavelength corresponding to a Fraunhoffer line in the solar spectrum.

Tunable ytterbium-doped solid state laser

A continuous wave(CW) activator ion doped fiber laser is presented which lases at a normally self-terminating laser transition at a slope efficiency greater than that achieved by a self-terminating fiber laser. Two laser transitions, one corresponding to a self-terminating laser transition and the other to a transition out of the lower level of the self-terminating transition, are simultaneously stimulated in the activator ion doped fiber. Through simultaneous lasing of the two wavelengths corresponding to these transitions, the lower level of the self-terminating transition is sufficiently depopulated so that CW operation is achieved.

Rare earth ion doped CW cascade fiber laser

In a preferred embodiment, a Tm.sup.3+ :YAG laser crystal and a Ho.sup.3+ :YAG laser crystal are placed within a reflective path of a laser cavity for intracavity pumping the Ho.sup.3+ :YAG laser crystal. The Tm.sup.3+ :YAG laser crystal emits a substantially 2.0 .mu.m laser emission after being resonantly end-pumped by a pump beam at a wavelength of about 785 nm and the substantially 2.0 .mu.m laser emission is used to pump the Ho.sup.3+ :YAG laser crystal. The intracavity-pumped Ho.sup.3+ :YAG laser crystal emits an output laser emission at substantially 2.1 .mu.m. The slope efficiency of the Ho.sup.3+ :YAG laser crystal output power is about 40% of the pump power absorbed by the Tm.sup.3+ :YAG laser crystal.

Intracavity-pumped 2.1 .mu.m Ho.sup.3+ :YAG laser

A continuous wave modelocked laser is provided which generates output pul having a duration in the picosecond range at a repetition rate in the MHz to GHz ranges. The laser includes a laser cavity defined by spaced, opposed reflective member forming a reflective path therebetween; a host laser crystal disposed in the cavity; an acousto-optic modulator disposed between the host laser crystal and one reflective member for modulating the output of the host laser crystal; and a birefringent filter, disposed in the laser cavity between the host laser crystal and the one reflective member, for tuning the laser emission to any one of a plurality of wavelengths within a range between 1.86 .mu.m and 2.14 .mu.m. A pump source pumps the host laser crystal at a wavelength of substantially 785 nm. A collimating plano-convex lens is disposed so that the planar face thereof faces the laser crystal. A mechanical device adjusts the length of the reflective path by axially displacing the one reflective member in the laser cavity so as to match the cavity round trip time to the second harmonic of the drive frequency of the acoustic-optic modulator.

Two-micron modelocked laser system

An optical system for end-pumping the gain medium of a three-level or a self-terminating solid state laser with the optical output from a wide aperture laser diode bar is disclosed. In a preferred embodiment, the optical system includes: a laser diode bar for emitting from an elongated emissive area thereof a bright light having a lateral divergence and a transverse divergence; and an optical assembly disposed between the laser diode bar and the three-level solid state laser for collecting and focusing the bright light into a relatively small high-intensity spot to end-pump the gain medium of the three-level or self-terminating solid state laser.

System for end-pumping a solid state laser using a large aperture laser

A flashpumped, tunable, two-micron, solid state laser is disclosed in which laser spiking is suppressed. The solid state laser comprises: a laser cavity defined by a first reflective element and an output coupler reflective element to form a reflective path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material doped with preselected activator ions sufficient to produce a pulse of laser emission at a desired laser transition wavelength in a range between about 1.9 microns and about 2.1 microns when the crystal is optically excited to produce the laser emission; a pulsed flashlamp for optically exciting the laser crystal to produce a pulse of laser emission at the desired laser transition wavelength; a tuner disposed in the laser cavity between the laser crystal and one of the reflective elements for tuning the laser emission to the desired laser transition wavelength in the range of wavelengths between about 1.9 microns and about 2.1 microns; optical plates oriented at Brewster's angle in the reflective path for suppressing oscillation of undesired wavelengths within the laser cavity; and a nonlinear crystal disposed in the reflective path to enable the laser to emit through the output coupler reflective element a smooth, long pulse of laser emission without spiking at the desired laser transition wavelength.

Suppression of relaxation oscillations in flashpumped, two-micron

A laser system and method for producing a laser emission at a wavelength of substantially 2.8 microns and having a quantum efficiency of at least unity and a slope efficiency of about 36%. In a preferred embodiment of the invention, the laser system comprises a laser cavity defined by first and second reflective elements with one of the reflective elements operating as an output coupler; a crystal disposed in the laser cavity and having a GSGG host material doped with a preselected percent concentration of erbium, the GSGG host material and preselected percent concentration of erbium being selected so as to provide a quantum efficiency of at least unity by the .sup.4 I.sub.13/2 +.sup.4 I.sub.13/2 .fwdarw..sup.4 I.sub.9/2 +.sup.4 I.sub.15/2 upconversion process and a slope efficiency of about 36% when the crystal is resonantly pumped; and a resonant pump laser for directly pumping the .sup.4 I.sub.11/2 upper laser state of the erbium with a pump beam to cause the crystal to produce a laser emission corresponding to the .sup.4 I.sub.11/2 .fwdarw..sup.4 I.sub.13/2 laser transition having a wavelength of substantially 2.8 microns.

Resonantly pumped, erbium-doped, GSGG, 2.8 micron, solid state laser

A tunable solid state laser for producing a laser emission at any desired w or high laser gain transition in a predetermined range of wavelengths is disclosed. The tunable solid state laser comprises: a laser cavity defined by a first reflective element and an output coupler reflective element to form a reflective path therebetween; a laser crystal disposed in the laser cavity; means for optically exciting the laser crystal to produce a laser emission in the predetermined range of wavelengths; a tunable element disposed in the laser cavity between the laser crystal and one of the reflective elements for tuning the laser emission to any desired laser transition in the predetermined range of wavelengths; and a plurality of optical plates oriented at Brewster's angle in the reflective path in the laser cavity for suppressing oscillation of undesired wavelengths within the laser cavity, the optical plates being transparent to the laser emission over the predetermined range of wavelengths. The tunable solid state laser can further include an aperture disposed in the reflective path in the laser cavity to allow the laser to lase in the laser cavity only at the lowest order spatial transverse mode of the desired wavelength in the predetermined range of wavelengths.

Tunable solid state laser with high wavelength selectivity over a

A room temperature solid state laser for producing a laser emission at a wavelength of substantially 2.09 microns is disclosed. In a preferred embodiment, the laser includes: a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material capable of accepting Cr.sup.3+ sensitizer ions, Tm.sup.3+ sensitizer ions and Ho.sup.3+ activator ions; an amount of Cr.sup.3+ sensitizer ions between about 0.3% and about 2% dispersed within the host material; an amount of Tm.sup.3+ sensitzer ions between about 3% and about 12% dispersed within the host material; and an amount of Ho.sup.3+ activator ions between about 0.1% and about 0.7% dispersed within the host material; and flashlamp and means for exciting the laser crystal to produce a laser emission at substantially 2.09 microns with a slope efficiency of at least 4%, and preferably of at least 5%.

Room-temperature, flashpumped, 2.09 micron solid state laser

A laser system and method for producing a laser emission at a wavelength of ubstantially 2.8 microns is disclosed. In a preferred embodiment of the invention, the laser system comprises a crystal having a host material doped with erbium; a laser cavity defined by first and second reflective elements at opposing ends of the crystal to form a reflective path therebetween; and resonant pumping means for directly pumping the .sup.4 I.sub.11/2 upper laser state of the erbium with a pump beam at a preselected wavelength to cause the erbium-doped crystal to produce a laser emission corresponding to the .sup.4 I.sub.11/2 .fwdarw..sup.4 I.sub.13/2 laser transition having a wavelength of substantially 2.8 microns, a portion of the laser emission at substantially 2.8 microns being outputted from one of the first and second reflective elements.

Growing community of inventors

Springfield, VA, United States of America

Leon Esterowitz