Gas transport laser system

A gas transport laser system, comprising:

• a pressurizable vessel having a cylindrically shaped internal surface for minimizing the surface area for contact with a laser gas within the vessel for reducing frictional contact with the laser gas and the area exposed to any corrosive laser gas;
• a structure having a cylindrically shaped external surface, the structure having an axis substantially parallel to the axis of the vessel and being positioned within the vessel so as to form a laser chamber between the external surface of the structure and the internal surface of the vessel;
• means for sealing the structure within the vessel so as to contain the laser gas in the laser chamber;
• gas recirculating means for flowing the laser gas through the laser chamber in a flow path substantially tangential to the external surface of the structure, the flow path having a minimal head loss;
• gas exciting means positioned within the laser chamber at a discharge location for selectively producing a gas discharge;
• and
• optically resonant means having an axis substantially parallel to the axis of the vessel and aligned with the discharge location for producing coherent radiation in response to a gas discharge.

An excimer laser system for producing coherent radiation, comprising:

• a pressurizable vessel having a cylindrically shaped internal surface for minimizing the surface area for contact with a gas mixture consisting of a rare gas and a molecular monohalide gas within the vessel for reducing frictional contact with the gas mixture and the area exposed to the monohalide gas;
• a structure having a cylindrically shaped external surface, the structure having an axis substantially parallel to the axis of the vessel so as to form a laser chamber between the external surface of the structure and the internal surface of the vessel;
• means for sealing the structure within the vessel so as to contain the gas mixture in the laser chamber;
• gas recirculating means for flowing the laser gas through the laser chamber in a flow path substantially tangential to the external surface of the structure, the flow path having a minimal head loss;
• gas exciting means positioned within the laser chamber at a discharge location for producing in the laser chamber a laser medium comprising a polyatomic excimer molecule from reaction of the rare gas in a metastable state and the molecular monohalide gas;
• and
• optically resonant means having an axis substantially parallel to the axis of the vessel and aligned with the discharge location for producing coherent radiation in response to a gas discharge.

A pulsed excimer laser system for producing emitted laser energy by an electrical discharge in a gas mixture and cyclic reformation, comprising:

• a pressurizable vessel having a cylindrically shaped internal surface for minimizing the surface area for contact with a gas mixture consisting of a rare gas and a molecular monohalide gas within the vessel for reducing frictional contact with the gas mixture and the area exposed to the monohalide gas;
• a structure having a cylindrically shaped external surface, the structure having an axis substantially parallel to the axis of the vessel so as to form a laser chamber between the external surface of the structure and the internal surface of the vessel;
• means for sealing the structure within the vessel so as to contain the gas mixture in the laser chamber;
• gas recirculating means for flowing the gas mixture through the laser chamber in a flow path substantially tangential to the external surface of the structure, the flow path having a minimal head loss;
• first and second electrodes supported within the vessel for forming a gap therebetween;
• a source of pulsed electrical power connected to the electrodes for producing an electrical discharge across the gap at pressures optimized for lasing action for producing in the laser chamber a laser medium comprising a polyatomic excimer molecule consisting of the rare gas in a metastable state and the halogen of the molecular monohalide gas;
• a buffer gas contained within the vessel and selected for aiding electrical discharge uniformity and aiding in the excitation of the gas mixture and to provide vibrational relaxation of the laser medium in its electronic state;
• means disposed within the vessel for preionizing the gas mixture within the vessel immediately prior to the electrical discharge produced by the source of pulsed electrical power;
• and
• at least two reflective surfaces disposed and aligned relative to the vessel for producing optical feedback for the emitted laser energy.

A method for producing coherent radiation, comprising the steps of:

• selecting a gas mixture;
• forming a laser chamber between a cylindrically shaped internal surface of a vessel and a cylindrically shaped external surface of a structure positioned and sealed within the vessel so that the axis of the structure is substantially parallel to the axis of the vessel;
• containing the selected gas mixture in the laser chamber;
• flowing the gas mixture through the laser chamber in a flow path so as to recirculate the gas mixture between the internal surface of the vessel and the external surface of the structure;
• selectively producing a gas discharge within the laser chamber at a discharge location;
• and
• disposing a reflective surface and a partially reflective surface in alignment with the discharge location for producing optical feedback for the emitted laser energy.