Mode-locked laser using non-linear self-focusing element
Granted: January 7, 1992
Patent Number:
5079772
A passively mode-locked laser (110) is disclosed that includes a resonant cavity (112, 114) having a gain medium (116) therein. A transmissive element (116), which may be the gain medium, is also located in the cavity and is formed from a material which varies the two-dimensional, lateral spatial profile of the beam with respect to intensity due to the Kerr effect. The resonator is arranged such that the round trip gain of the system increases with respect to the intensity of the beam so…
Apparatus for measuring the mode quality of a laser beam
Granted: January 7, 1992
Patent Number:
5078491
A method and apparatus for determining the quality of a multimode laser beam (10). In the preferred embodiment, the apparatus includes a lens (32) for creating a transformed or imaged waist from the input beam. The location of the transformed beam waist and its diameter are then determined. These steps can be carried out by chopping the beam using a rotating hub (34) having apertures (36,38) for selectively passing the beam. Preferably, one of the apertures has a pair of 45.degree. knife…
Apparatus for measuring the mode quality of a laser beam
Granted: December 3, 1991
Patent Number:
5069527
A method and apparatus for determining the quality of a multimode laser beam (10). In the preferred embodiment, the apparatus includes a lens (32) for creating a transformed or imaged waist from the input beam. The location of the transformed beam waist and its diameter are then determined. These steps can be carried out by chopping the beam using a rotating hub (34) having apertures (36, 38) for seletively passing the beam. Preferably, one of the appertures has a pair of 45.degree.…
Apparatus for measuring the mode quality of a laser beam
Granted: November 12, 1991
Patent Number:
5064284
A method and apparatus for determining the quality of a multimode laser beam (10). In the preferred embodiment, the apparatus includes a lens (32) for creating a transformed or imaged waist from the input beam. The location of the transformed beam waist and its diameter are then determined. These steps can be carried out by chopping the beam using a rotating hub (14) having apertures (36,38) for selectively passing the beam. Preferably, one of the apertures has a pair of 45.degree. knife…
Isotopic CO.sub.2 laser and method of use for medical treatment
Granted: November 5, 1991
Patent Number:
5062842
A medical treatment laser is disclosed that minimizes absorption of laser energy along the beam path by using a lasing medium having a principal emission at a wavelength shifted from the absorption wavelength. In the preferred embodiment, a CO.sub.2 laser filled with the .sup.13 C.sup.16 O.sub.2 isotope is used. The .sup.13 C.sup.16 O.sub.2 isotope generates a laser beam having a principal emission wavelength near 11.2 microns. The absorption of this wavelength in the conventional…
Multilayer optical filter for producing colored reflected light and neutral transmission
Granted: October 29, 1991
Patent Number:
RE33729
A short-wave-pass optical filter, that includes a partially absorbing or transparent substrate coated by a set of layers having specified quarter-wave optical thickness, and is designed to reflect visible radiation of a selected color while transmitting visible radiation and maintaining a neutral color balance. The coating includes layers having a high refractive index alternating with layers having a low refractive index. The refractive indices and layer thicknesses are selected so that…
Single frequency ring laser with two reflecting surfaces
Granted: October 1, 1991
Patent Number:
5052815
A ring laser is provided with only two reflecting surfaces to define the cavity. A gain medium is located between the reflecting surfaces. At least one optical interface is located within the cavity and is oriented such that the beam will be deflected by refraction to create a ring path. The angle of incidence of the beam with the interface should be less than Brewster's angle and the surface should have an antireflective coating. The interface can be located on the lasant material, on a…
High power laser with focusing mirror sets
Granted: September 24, 1991
Patent Number:
5052017
A laser system employing one or more mirror sets having substantially astigmatism-free focusing power sufficient to maintain a desired laser beam diameter, for example, to compensate for thermally-induced distributed lensing. In one class of preferred embodiments, the invention is a high power gas laser system having a folded optical cavity with a periodic intracavity refocusing means to compensate for distributed negative thermal lensing in the hot plasma that comprises the active…
Laser with actively stabilized etalon for single frequency operation
Granted: September 10, 1991
Patent Number:
5048031
An actively stabilized laser is disclosed which includes a temperature tunable etalon in the laser cavity for single frequency operation. The operation of the laser is actively monitored to detect variations induced by changes in the length of the resonator. These changes tend to cause the frequency of the selected longitudinal mode to shift so that it is no longer aligned with the peak of the transmission curve of the etalon. When this misalignment occurs, operation deteriorates. By…
Method and apparatus for controlling the power supply of a laser operating in a pulse mode
Granted: September 10, 1991
Patent Number:
5048033
An electronics controller for controlling the power supply of a laser operating in a pulse mode is disclosed. The power supply is of the type having a resonant DC converter, charging a capacitive storage means with an inverter stage driving the laser discharge tube. The current supplied to the laser discharge tube is monitored. In addition, the voltage of the capacitive storage means is also measured. Set points for the current, the voltage, and on/off are provided to the electronics…
Longitudinally laser pumped laser with compensation for thermal lens effects
Granted: September 3, 1991
Patent Number:
5046070
A laser system is disclosed wherein a solid state gain medium (30) is longitudinally pumped with the beam (40) from another laser (42). The laser is configured with an optically stable resonator while at the same time matching the shape of the pump beam to the shape of the cavity beam in the gain medium. Optimum matching is achieved by taking into consideration thermal lens effects in the gain medium resulting from absorption of the pump beam.
Mode-locked laser
Granted: August 13, 1991
Patent Number:
5040182
Mode-locked pulsed output is induced in a laser by introducing a varying frequency dependent loss in the cavity. The varying, frequency dependent loss allows a large number of longitudinal modes to oscillate. In one of the preferred embodiments of the subject invention, the varying frequency dependent loss is generated by reciprocating one of the mirrors of the resonator. In this embodiment, the laser has a resonator with a primary light path defined by first and second end mirrors. A…
Mid-infrared laser arthroscopic procedure
Granted: August 6, 1991
Patent Number:
5037421
A Ho:YAG laser is coupled to a needle tip through a flexible, fiber optic cable for performing endoscopic and arthroscopic surgery.
Apparatus for autocorrelating optical radiation signals
Granted: July 23, 1991
Patent Number:
5033853
An apparatus (12) generates information about the width of pulses in an optical train using an autocorrelation technique. In the apparatus, the incoming beam (10) is split into two paths (10a, 10b). The path length of one of the beams (10b) is varied using a reciprocating stage (40) having a reflector (50) mounted thereon. The stage is driven by a cam (42) rotating at a constant speed. A portion (42b) of the curvature of the cam is arranged such that the distance between the rotational…
Laser alignment servo method and apparatus
Granted: July 16, 1991
Patent Number:
5033061
A servo alignment method and apparatus for maintaining laser beam alignment. An operating parameter of the laser (such as output beam power) is measured, and error signals are generated from the measured operating parameter signal for controlling the laser beam alignment. In one class of embodiments, modulation signals are supplied to an intra-cavity component of a laser system to modulate the beam path. The beam path may be modulated by reciprocating a laser resonator mirror about a…
High power laser with focusing mirror sets
Granted: June 11, 1991
Patent Number:
5023886
A laser system employing one or more mirror sets having substantially astigmatism-free focusing power sufficient to maintain a desired laser beam diameter, for example, to compensate for thermally-induced distributed lensing. In one class of preferred embodiments, the invention is a high power gas laser system having a folded optical cavity with a periodic intracavity refocusing means to compensate for distributed negative thermal lensing in the hot plasma that comprises the active…
Gas laser
Granted: May 7, 1991
Patent Number:
5014281
A gas laser includes a laser gas circuit having a by-pass line. The by-pass line includes a condenser for removing water vapor. During normal operation, the laser gas flows through the by-pass line as well as through the remaining portion of the laser gas circuit so that the water vapor portion in the laser gas flowing through the by-pass line is partly removed by the condenser. For the purpose of defrosting the condenser, the by-pass line is isolated from the rest of the laser gas…
Kinematic resonator support
Granted: March 19, 1991
Patent Number:
5000557
The subject invention relates to a laser system where the length stability of the resonant cavity is important. Three unique mounting assemblies are disclosed to improve the stability of the cavity. The first assembly relates to a kinematic support for mounting an Invar bar. The second assembly defines a once-piece gimbal pivot ring designed to mount laser mirrors. The final aspect of the invention includes a mounting assembly designed to automatically compensate for changes in length of…
Stabilized synchronously pumped dye laser
Granted: March 12, 1991
Patent Number:
4999840
A length stabilized, dispersion compensated synchronously pumped mode locked dye laser is disclosed. The output of the dye laser is actively stabilized by monitoring the output power thereof and generating an error signal for actively adjusting the cavity length. The operation is enhanced by actively controlling the power of the pump pulses exciting the dye laser so that the power fluctuations in the dye laser are due primarily to fluctuations in cavity length. Stability is also enhanced…
Stabilized synchronously pumped dye laser
Granted: March 5, 1991
Patent Number:
4998254
A length stabilized, dispersion compensated synchronously pumped mode locked dye laser is disclosed. The output of the dye laser is actively stabilized by monitoring the output power thereof and generating an error signal for actively adjusting the cavity length. The operation is enhanced by actively controlling the power of the pump pulses exciting the dye laser so that the power fluctuations in the dye laser are due primarily to fluctuations in cavity length. Stability is also enhanced…
