H01S3/223

Widely tunable compact terahertz gas lasers

Disclosed is a laser system including a first laser and a second laser. The first laser includes a laser cavity, and a gas phase molecular gain medium disposed in the laser cavity, the gain medium having an absorption band. The second laser is a solid state laser configured to be continuously tunable, with respect to an emission wavelength of the second laser, over the absorption band of the gain medium, and the second laser is tuned to pump rotational vibrational transitions in the gain medium to achieve a rotational population inversion.

Methods and systems for aligning master oscillator power amplifier systems

The present disclosure provides a method for aligning a master oscillator power amplifier (MOPA) system. The method includes ramping up a pumping power input into a laser amplifier chain of the MOPA system until the pumping power input reaches an operational pumping power input level; adjusting a seed laser power output of a seed laser of the MOPA system until the seed laser power output is at a first level below an operational seed laser power output level; and performing a first optical alignment process to the MOPA system while the pumping power input is at the operational pumping power input level, the seed laser power output is at the first level, and the MOPA system reaches a steady operational thermal state.

GAS LASER AMPLIFIER, GAS LASER APPARATUS, EUV LIGHT GENERATION APPARATUS, AND EUV EXPOSURE APPARATUS

A gas laser amplifier includes a housing, discharge electrode pairs, and an optical resonator. The housing includes an entrance window that allows entry of a first laser beam from outside and an exit window that allows exit of the first laser beam amplified. Each of the discharge electrode pairs excites a laser gas supplied between discharge electrodes facing each other in the housing. The optical resonator causes a second laser beam to oscillate with a gain of the excited laser gas in a non-incident state where the first laser beam from outside the housing does not enter the housing through the entrance window. In an incident state where the first laser beam enters the housing through the entrance window, the optical resonator suspends the oscillation of the second laser beam.

CO2 BEAM SOURCE COMPRISING A CATALYST

A CO.sub.2 beam source includes a discharge tube in which a laser gas serves as a laser medium, a fan for supplying the laser gas into the discharge tube via a supply element and for removing the laser gas from the discharge tube via a removal element in a closed laser gas circuit, and a catalyst for catalysing oxidation of dissociation products formed upon excitation of the laser gas. The catalyst includes precious metal nanoparticles applied to a substrate. The catalyst is arranged with clearance from the discharge tube in the flow direction of the laser gas within the closed laser gas circuit in order to reduce deposition of degradation products formed in the discharge tube upon excitation of the laser gas compared to an arrangement within the discharge tube. A temperature of the at least one catalyst during operation of the CO.sub.2 beam source is at least 60? C.

REVERSING COFFEE-RING EFFECT BY LASER-INDUCED DIFFERENTIAL EVAPORATION
20190314872 · 2019-10-17 ·

Disclosed are methods, devices and systems to cause differential evaporation of micro-droplets in a scalable fashion. In some embodiments, an attenuated laser is used to focus an attenuated laser power to the center of an aqueous solution droplet, producing a differential evaporative flux profile that is peaked at the droplet apex. The laser-induced differential evaporation described herein is a breakthrough in the enrichment and focused deposition of water-soluble molecules such as nucleic acids, proteins, inks, and other small molecules. Disclosed is a general solution to remove the coffee-ring effect, ubiquitous in the drying process of aqueous droplets that causes many adverse outcomes. The disclosed techniques enable new paradigms in liquid biopsy combinational analysis, microarray fabrication, and ink-jet printing.

Laser unit

A laser unit may include a laser chamber including a pair of discharge electrodes that are opposed to each other in a first direction with an electrode gap interposed in between and are configured to provide a discharge width in a second direction, orthogonal to the first direction, smaller than the electrode gap; and an optical resonator including a first optical member and a second optical member that are opposed to each other in a third direction orthogonal to both the first direction and the second direction with the discharge electrodes interposed in between, and configured to amplify laser light generated between the discharge electrodes and output amplified laser light, the optical resonator satisfying the following expression to configure a stable resonator in the second direction:
0<G1.Math.G2<1 where G1 is a G parameter of the first optical member, and G2 is a G parameter of the second optical member.

Laser unit

A laser unit may include a laser chamber including a pair of discharge electrodes that are opposed to each other in a first direction with an electrode gap interposed in between and are configured to provide a discharge width in a second direction, orthogonal to the first direction, smaller than the electrode gap; and an optical resonator including a first optical member and a second optical member that are opposed to each other in a third direction orthogonal to both the first direction and the second direction with the discharge electrodes interposed in between, and configured to amplify laser light generated between the discharge electrodes and output amplified laser light, the optical resonator satisfying the following expression to configure a stable resonator in the second direction:
0<G1.Math.G2<1 where G1 is a G parameter of the first optical member, and G2 is a G parameter of the second optical member.

LASER APPARATUS AND EXTREME ULTRAVIOLET LIGHT GENERATION SYSTEM
20190293922 · 2019-09-26 · ·

A laser apparatus may include: a mirror configured to reflect a laser beam; an actuator configured to operate the mirror; and a controller configured to transmit a movement instruction to the actuator, wherein the controller predicts a movement completion time of the actuator, and transmits a polling signal so that the actuator receives the polling signal after expiration of the predicted movement completion time.

CONDUCTIVELY-COOLED SLAB LASER
20190280448 · 2019-09-12 ·

A carbon dioxide gas-discharge slab-laser is assembled in a laser-housing. The laser-housing is formed from a hollow extrusion. An interior surface of the extrusion provides a ground electrode of the laser. Another live electrode is located within the extrusion, electrically insulated from and parallel to the ground electrode, forming a discharge-gap of the slab-laser. The electrodes are spaced apart by parallel ceramic strips. Neither the extrusion, nor the live electrode, include any direct fluid-cooling means. The laser-housing is cooled by fluid-cooled plates attached to the outside thereof.

Flat-folded ceramic slab lasers

In at least one illustrative embodiment, a laser may include a ceramic body defining a chamber containing a laser gas. The chamber may include first and second slab waveguide sections extending along parallel first and second axes and a third slab waveguide section extending along a perpendicular third axis. Respective first ends of the first and second slab waveguide sections may be positioned adjacent opposite ends of the third slab waveguide section. The laser may also include first and second end mirrors positioned at respective second ends of the first and second slab waveguide sections, a first fold mirror positioned near an intersection of the first and third axes at a 45-degree angle to both the first and third axes, and a second fold mirror positioned near an intersection of the second and third axes at a 45-degree angle to both the second and third axes, such that the first, second, and third slab waveguide sections waveguide recirculating light that is polarized orthogonal to a plane defined by the first, second, and third axes.