Laser resonator with improved output beam characteristics
AssigneeThe Twentyfirst Century Corporation
InventorJean-Charles L. Mombo Caristan
Life of this patent
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Abstract
A high power laser resonator with improved efficiency of the lasing mechanism, for outputting a laser beam (6) of improved geometric and quality factors characteristics, adapted to the specific needs of high-speed-high-power laser material processing. In particular, conditions for output laser beam (6) geometric dimensions Dx, Dy, and corresponding quality factors, Kx, Ky, are set, such that the laser beam could be usable directly from the output of the resonator without adding beam shaping optics, and such that a better optimization of the extraction efficiency of laser power can be achieved. These four factors are in specific relationship with the wavelength of the laser radiation and the output laser power.
Claims19
A laser resonator apparatus comprising
- two end mirrors separated by a geometrical distance Lg and an optical length L, the optical length L being equal to the distance travelled by light in a one way trip from one end-mirror to the other end-mirror,
- an active medium between the two end mirrors,
- a pumping mechanism that excites atoms and molecules of the active medium and stimulates emission of laser radiation between the end-mirrors, such that an output laser beam of wavelength, .lambda., and of average output power, P, of at least 3 kW is produced from the resonator,
- a resultant aperture defining the output laser beam's cross section dimensions Dx and Dy in two transverse x-direction and y-direction, perpendicular to the z-direction of propagation of the laser beam immediately as it exits the resonator, the x-direction and z-direction defining the xz-plane, and the y-direction and z-direction defining the yz-plane, and
- respective quality factors Kx and Ky in the two transverse x-direction and y-direction,
- characterized in that the beam characteristics Dx, Dy, Kx, Ky satisfy the following:
- 1.5.ltoreq.(Kx*Dy)/(Ky*Dx)
- or
- 1.5.ltoreq.(Ky*Dx)/(Kx*Dy)
- and
- .vertline.Kx-Ky.vertline./(Kx+Ky).gtoreq.0.125.
A laser resonator comprising
- two end mirrors separated by a geometrical distance Lg and an optical length L, the optical length L being equal to the distance travelled by light in a one way trip from one end-mirror to the other end-mirror,
- an active medium between the two end mirrors,
- a pumping mechanism that excites atoms and molecules of the active medium and stimulates emission of laser radiation between the end-mirrors, such that an output laser beam of wavelength, .lambda., and of average output power, P, of at least 3 kW is produced from the resonator,
- a resultant aperture defining the output laser beam's cross section dimensions Dx and Dy in two transverse x-direction and y-direction, perpendicular to the z-direction of propagation of the laser beam immediately as it exits the resonator, the x-direction and z-direction defining the xz-plane, and the y-direction and z-direction defining the yz-plane, and
- respective quality factors Kx and Ky in the two transverse x-direction and y-direction,
- characterized in that the beam characteristics Dx, Dy, Kx, Ky satisfy the following:
- 1.5.ltoreq.Kx*Dy/(Ky*Dx) or 1.5.ltoreq.Ky*Dx/(Kx*Dy)
- where Dx.gtoreq.Dy and:
- Kx*Dx.ltoreq.(P*0.6 mm.sup.2.kW.sup.-1) (.lambda..sup.2 *50).
A method of welding using a high energy density radiation beam produced by a laser resonator apparatus, the laser resonator apparatus comprising:
- two end mirrors separated by a geometrical distance Lg and an optical length L, the optical length L being equal to the distance travelled by light in a one way trip from one end-mirror to the other end-mirror,
- an active medium between the two end mirrors,
- a pumping mechanism that excites atoms and molecules of the active medium and stimulates emission of laser radiation between the end-mirrors, such that an output laser beam of wavelength, .lambda., and of average output power, P, of at least 3 kW is produced from the resonator,
- a resultant aperture defining the output laser beam's cross section dimensions Dx and Dy in two transverse x-direction and y-direction, perpendicular to the z-direction of propagation of the laser beam immediately as it exits the resonator, the x-direction and z-direction defining the xz-plane, and the y-direction and z-direction defining the yz-plane, and
- respective quality factors Kx and Ky in the two transverse x-direction and y-direction,
- characterized in that the beam characteristics Dx, Dy, Kx, Ky satisfy the following:
- 1.5.gtoreq.Kx*Dy/(Ky*Dx) or 1.5.ltoreq.Ky*Dx/(Kx*Dy)
- .vertline.Kx-Ky.vertline./(Kx+Ky).ltoreq.0.125.
Dependencies are inferred from the claim text.