Vacuum ultraviolet laser wavelength measuring apparatus

A vacuum ultraviolet laser wavelength measuring apparatus having spectral means for generating an optical pattern corresponding to wavelength characteristics of an incident laser beam and measuring wavelength characteristics of a laser beam in a vacuum ultraviolet region oscillating from a vacuum ultraviolet laser on the basis of the optical pattern, comprising:

• a fluorescent screen for generating a fluorescent pattern, with use of a first imaging lens, having an intensity distribution corresponding to an intensity distribution of the incident optical pattern;
• a pattern detector for measuring the intensity distribution of the fluorescent pattern generated from the fluorescent screen;
• and
• an arithmetic unit for calculating the wavelength characteristics of said laser beam on the basis of the intensity distribution of the measured fluorescent pattern, wherein
• said spectral means comprises a plurality of concave mirrors and a diffraction grating for diffracting a laser beam at an angle corresponding to the wavelength characteristics of the incident laser beam,
• wherein the diffracted beam is condensed in one side of said fluorescent screen, the fluorescent pattern having an intensity distribution corresponding to an intensity distribution of the diffracted beam is generated in the other side of said fluorescent screen, and
• the fluorescent pattern is imaged on said pattern detector by using a second imaging lens.

A vacuum ultraviolet laser wavelength measuring apparatus having spectral means for generating an optical pattern corresponding to wavelength characteristics of an incident laser beam and measuring wavelength characteristics of a laser beam in a vacuum ultraviolet region oscillating from a vacuum ultraviolet laser on the basis of the optical pattern, comprising:

• a fluorescent screen for generating a fluorescent pattern, with use of a first imaging lens, having an intensity distribution corresponding to an intensity distribution of the incident optical pattern;
• a pattern detector for measuring the intensity distribution of the fluorescent pattern generated from the fluorescent screen;
• an arithmetic unit for calculating the wavelength characteristics of said laser beam on the basis of the intensity distribution of the measured fluorescent pattern, and
• an ultraviolet filter which does not transmit the laser beam in the vacuum ultraviolet region and transmits the laser beam having a wavelength close to a wavelength of the fluorescent pattern in the front of said pattern detector.

A vacuum ultraviolet laser wavelength measuring apparatus having spectral means for generating an optical pattern corresponding to wavelength characteristics of an incident laser beam and measuring wavelength characteristics of a laser beam in a vacuum ultraviolet region oscillating from a vacuum ultraviolet laser on the basis of the optical pattern, comprising:

• a fluorescent screen for generating a fluorescent pattern, with use of a first imaging lens, having an intensity distribution corresponding to an intensity distribution of the incident optical pattern;
• a pattern detector for measuring the intensity distribution of the fluorescent pattern generated from the fluorescent screen;
• an arithmetic unit for calculating the wavelength characteristics of said laser beam on the basis of the intensity distribution of the measured fluorescent pattern, wherein
• said fluorescent screen has a movable actuator which is movable by a predetermined distance perpendicularly to an optical axis of the incident laser beam and is movably installed by this movable actuator.