Laser resonator for improving narrow band emission of an excimer laser

A method of optimizing spectral purity, bandwidth and output power of a spectral beam from an excimer or molecular fluorine laser including a laser active medium, a resonator, an output coupler, a processor, an energy detector, a spectrometer and a wavelength selection unit, comprising the steps of:

• selecting a refractive optical component having a curved surface and providing the refractive optical component within the resonator for adapting a divergence of the spectral beam;
• measuring beam energy and a spectral parameter with the energy detector and spectrometer respectively, and sending signals to the processor indicative of the beam energy and spectral parameter;
• and
• aligning the optical component within the resonator for optimizing spectral purity, bandwidth and output power of the beam based on at least one of the beam energy and spectral parameter signals sent to the processor.

An excimer laser, comprising

• an active laser medium for emitting a spectral beam;
• a resonator defining an optical path intersecting said active medium;
• means for output coupling the spectral beam from the resonator;
• means for selecting and narrowing the wavelength of the spectral beam;
• an adjustable aperture within the resonator for improving spectral purity and bandwidth;
• and
• an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the adjustable aperture is adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer laser, comprising

• an active laser medium for emitting a spectral beam;
• a resonator defining an optical path intersecting said active medium;
• means for output coupling the spectral beam from the resonator;
• means for selecting and narrowing the wavelength of the spectral beam;
• an adjustable aperture within the resonator for improving spectral purity and bandwidth wherein the aperture is located near the grating, and further comprising a energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the adjustable aperture is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer or molecular fluorine laser, comprising

• an active laser medium surrounded by a resonator and a discharge circuit for emitting a spectral beam;
• a line-narrowing unit for narrowing the bandwidth of the spectral beam;
• and
• at least one optical component having a curved surface wherein the curvature is selected for improving spectral purity, and further comprising an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the curvature of the curved surface of said optical component is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer or molecular fluorine laser, comprising

• an active laser medium surrounded by a resonator and a discharge circuit including a plurality of electrodes for generating a laser beam;
• a line-narrowing unit within the resonator narrowing the bandwidth of the beam;
• and
• an adjustable aperture within the resonator for improving spectral purity and bandwidth, wherein the aperture is located just in front of the grating, and further comprising an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the adjustable aperture is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer or molecular fluorine laser, comprising

• an active laser medium surrounded by a resonator and a discharge circuit including a plurality of electrodes for generating a laser beam;
• a line-narrowing unit within the resonator narrowing the bandwidth of the beam;
• and
• an adjustable aperture within the resonator for improving spectral purity and bandwidth, and further comprising an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the adjustable aperture is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer or molecular fluorine laser, comprising

• an active laser medium surrounded by a resonator and a discharge circuit for emitting a spectral beam;
• a line-narrowing unit for narrowing the bandwidth of the spectral beam;
• and
• at least one optical component having a curved surface wherein the curvature is selected for improving spectral purity by between 20% and 50% while introducing a power loss of less than 10% wherein the radius of curvature of the curved surface is continuously adjustable, and further comprising an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the curvature of the curved surface of said optical component is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer or molecular fluorine laser, comprising:

• an active laser medium for generating a spectral beam at an original central wavelength;
• a resonator including a first reflecting surface and a second reflecting surface, an optical path intersecting said active medium being defined for said resonator for generating a laser beam;
• a wavelength selector for selecting a wavelength band from the spectral beam including a beam expander and a grating;
• and
• an aperture disposed between said beam expander and said grating for adapting a divergence of the resonating beam to improve and control spectral purity and bandwidth.

An excimer or molecular fluorine laser, comprising:

• an active laser medium for generating a spectral beam at an original central wavelength;
• a resonator including a first reflecting surface and a second reflecting surface, an optical path intersecting said active medium being defined for said resonator for generating a laser beam;
• a wavelength selector for selecting a wavelength band from the spectral beam including a beam expander and a grating;
• wherein said grating, which also serves as said first reflecting surface, and said second reflecting surface have curved surfaces of opposite curvature forming an unstable resonator, and wherein said curved surface of said second reflecting surface is adjustable;
• and
• an energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the curvature of the curved surface of said second reflecting surface is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.

An excimer laser, comprising:

• an active laser medium for emitting a spectral beam;
• a resonator defining an optical path intersecting said active medium;
• means for output coupling the spectral beam from the resonator;
• means for selecting and narrowing the wavelength of the spectral beam;
• an adjustable aperture within the resonator for improving spectral purity and bandwidth, wherein the aperture is located near the grating, and further comprising a energy detector and a spectrometer each for receiving a portion of the spectral beam, and a processor for receiving signals from each of the energy detector and the spectrometer, wherein the adjustable aperture is automatically adjusted when a signal is received from the processor based on information received from the spectrometer and the energy detector.