Resonator optics monitoring method
AssigneeLambda Physik AG
InventorMatthias Kramer
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Abstract
A technique for testing the quality of optical components of a line-narrowing module is performed on-line. As the wavelength tends to drift from a desired value when the optical components of the line-narrowing module are heated due to absorption, one or more optical components is adjusted such as by rotation to tune the wavelength back to the desired wavelength using a feedback loop. The amount of adjustment of these optical components is monitored for indirectly measuring, and thereby testing, the absorption or quality of the optical components.
Claims23
A method for testing quality of optics of a line-narrowing module of a laser emitting an output beam, comprising the steps of:
- operating said laser;
- adjusting one or more optical components of the line-narrowing module to compensate absorption-induced wavelength changes of the output beam;
- monitoring an amount of the adjusting of said one or more optical components;
- and
- determining the quality of the optics of the line-narrowing module based on the amount of adjusting performed to compensate the absorption-induced wavelength changes of the output beam.
A method for testing a quality of optics of a line-narrowing module of a laser emitting an output beam, comprising the steps of:
- operating said laser;
- adjusting an orientation of one or more optical components of the line-narrowing module to compensate wavelength changes of the output beam while said laser is operating;
- monitoring a parameter which varies based on the quality of the optics of the line-narrowing module;
- and
- determining the quality of the optics of the line-narrowing module based on variations in said parameter.
A method for stabilizing parameters of an output beam of a line-narrowed laser having a discharge chamber and a resonator having a line-narrowing module at least including a retro-reflective diffraction grating and an transmission interferometric device for reducing a bandwidth of said output beam, comprising the steps of:
- operating said laser at a repetition rate of at least 2 kHz;
- initially orienting said transmission interferometric device and said retro-reflective diffraction grating to initial orientations relative to said discharge chamber to have a transmission intensity peak and a reflection intensity peak, respectively, at a substantially same selected initial wavelength for reducing a characteristic emission wavelength of said output beam to less than 0.6 pm;
- adjusting one of said grating and said etalon to an adjusted orientation to compensate wavelength changes of the output beam incurred during operation of said laser;
- and
- adjusting the other of said grating and said interferometric device to another adjusted orientation, such that a reflection peak and a transmission peak of said grating and said interferometric device, respectively, are adjusted back substantially to said same selected initial wavelength,
- wherein said emission wavelength of said laser beam is stabilized at said initial wavelength while said grating and said interferometric device are each adjusted to said adjusted orientations different from said initial orientations relative to said discharge chamber.
Dependencies are inferred from the claim text.