Wavelength detector and wavelength calibration system

A wavelength detector that detects a wavelength of a laser beam outputted from an ultra violet laser device, the wavelength detector comprising:

• a discharge tube that includes a cylindrical anode and a cylindrical cathode that each have a through-hole formed therein, and that is configured so that an electrical property between the anode and the cathode changes due to an opto-galvanic effect when a laser beam having a predetermined first wavelength passes through the through-hole of the cathode in a state in which a DC voltage is applied to the anode;
• a high-voltage DC power source configured so as to apply a DC voltage to the anode;
• and
• a signal processing unit including a signal detection point for detecting a change in a signal level of the cathode,
• wherein the signal processing unit includes at least one of a low-pass filter connected to the signal detection point for suppressing the level of a photoelectric effect signal produced when the cathode is irradiated with the laser beam and a delay circuit that delays a signal detection timing in the signal detection point by a predetermined amount of time in order to suppress the detection of the photoelectric effect signal at the signal detection point.

A wavelength detector that detects a wavelength of an ultra violet laser beam, the wavelength detector comprising:

• a diffusion element that diffuses the laser beam;
• a light collection optical system that receives the laser beam from the diffusion element;
• a member including an aperture through which the laser beam collected by the light collection optical system passes;
• a discharge tube including a cylindrical anode, a cylindrical cathode, and a receptacle that seals the anode and the cathode;
• a high-voltage DC power source configured so as to apply a DC voltage to the anode;
• and
• an optical system that allows the laser beam that has passed through the aperture to pass through a through-hole of the cathode without directly irradiating the cathode.