USA As Represented by Secretary of the Navy

Robert C Stoneman

Leon Esterowitz

Joseph F Pinto

John M McMahon

Leon Esterowtiz

James G Lynn

A thulium-doped solid state laser is provided capable of operation at a wlength having a shallow absorption depth in tissue. The laser is comprised of a laser cavity defined by first and second reflecting surfaces opposing each other on an optical axis, a thulium-doped YALO crystal disposed in the cavity, and a pump source for pumping the crystal with a pump beam at a preselected wavelength to enable the crystal to emit a most preferred 1.94 micron laser output. The thulium-doped YALO crystal is preferably an a-cut crystal. Such alignment of this material provides a reliable mode at 1.94 microns which has excellent tissue absorption characteristics for medical applications. The length l of the crystal, the concentration N of the dopant and the transmissivity T of the output coupler, which define an expression Nl/T, can be varied as long as the expression Nl/T produces a value which does not exceed about 0.32 centimeters.

TM:Yalo, 1.94-micron, 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

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 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 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.

Resonantly pumped, erbium-doped, 2.8 micron solid state laser with high

A room-temperature, solid state laser for producing a CW laser emission cinuously tunable over the approximate spectral range of 1.86 to 2.14 microns is disclosed. In a preferred embodiment, the laser comprises: a diode pump laser for producing a CW pump beam at a preselected wavelength; a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a reflective path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material doped with a concentration of thulium activator ions sufficient to produce a CW laser emission in the range of a plurality of wavelengths determined by the Stark components in the .sup.3 F.sub.4 to .sup.3 H.sub.6 laser transition in the thulium activator ions when the laser crystal is pumped by the CW pump beam; and means disposed in the laser cavity between the laser crystal and the second reflective element for tuning the CW laser emission to any of the plurality of wavelengths within the range between approximately 1.86 microns and approximately 2.14 microns.

Tunable, continuous wave, thulium-doped, solid state laser

A room-temperature, laser-pumped, Q-switched, thulium-doped, solid state laser for producing pulses of laser emission at substantially 2 microns is disclosed. In a preferred embodiment, the laser comprises: a laser cavity defined by first and second reflective elements opposing each other on a common axis to form a reflective path therebetween; a laser crystal disposed in the laser cavity, the laser crystal having a host material doped with an amount of thulium activator ions sufficient to produce a laser emission at substantially 2 microns from the .sup.3 F.sub.4 to .sup.3 H.sub.6 laser transition in the thulium activator ions when the laser crystal is enabled and is pumped by a CW pump beam at a preselected wavelength; a pump laser for pumping the laser crystal with the CW pump beam at the preselected wavelength; and a Q-switch disposed in the laser cavity between the laser crystal and the second reflective element for periodically enabling the laser crystal to produce a pulsed laesr emission at substantially 2 microns when the laser crystal is also pumped by the CW pump beam.

Growing community of inventors

Alexandria, VA, United States of America

Robert C Stoneman