摘要:
Output beam parameters of a gas discharge laser are stabilized by maintaining a molecular fluorine component at a predetermined partial pressure using a gas supply unit and a processor. The molecular fluorine is subject to depletion within the discharge chamber. Gas injections including molecular fluorine can increase the partial pressure of molecular fluorine by a selected amount. The injections can be performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure. The amount per injection and/or the interval between injections can be varied, based on factors such as driving voltage and a calculated amount of molecular fluorine in the discharge chamber. The driving voltage can be in one of multiple driving voltage ranges that are adjusted based on system aging. Within each range, gas injections and gas replacements can be performed based on, for example, total applied electrical energy or time/pulse count.
摘要:
The stability of a gas discharge in an excimer or molecular fluorine laser system can be improved by generating multiple discharge pulses in the resonator chamber, instead of a single discharge pulse. Each of these discharges can be optimized in both energy transfer and efficient coupling to the gas. The timing of each discharge can be controlled using, for example, a common pulser component along with appropriate circuitry to provide energy pulses to each of a plurality of segmented main discharge electrodes. Applying the energy to the segmented electrodes rather than to a standard discharge electrode pair allows for an optimization of the temporal shape of the resulting superimposed laser pulse. The optimized shape and higher stability can allow the laser system to operate at higher repetition rates, while minimizing the damage to system and/or downstream optics.
摘要:
Method and system for providing stabilization techniques for high repetition rate gas discharge lasers with active loads provided in the discharge circuitry design which may include a resistance provided in the discharge circuitry.
摘要:
A laser for an excimer or molecular fluorine laser includes an electrode chamber connected with a gas flow vessel and having a pair of main electrodes and a preionization unit each connected to a discharge circuit. A spoiler is provided within the electrode chamber and is shaped to provide a more uniform gas flow through the discharge area between the main electrodes, to shield one of the preionization units from one of the main electrodes, and to reflect acoustic waves generated in the discharge area into the gas flow vessel for absorption therein. A spoiler unit may include a pair of opposed spoiler elements on either side of the discharge area. One or both main electrodes includes a base portion and a center portion which may be a nipple protruding from the base portion. The center portion substantially carries the periodic discharge current such that the discharge width is and may be significantly less than the width of the base portion. The curvatures of both main electrodes may conform to the curvature of the gas flow through the discharge chamber to further improve aerodynamic performance. A plurality of low inductive conducting ribs are connected to the grounded main electrode and shaped to provide a more uniform flow of gases through openings defined between adjacent ribs.
摘要:
A source of narrow-band coherent radiation has a first optical parametric oscillator (OPO 1) for producing seed radiation, and a second optical parametric oscillator (OPO 2), into which the seed radiation is input after passing through a wavelength-selective element (G). In order to stabilize and adjust the bandwidth of the radiation (14) emitted by the second optical parametric oscillator (OPO 2), radiation of this type is also input into the wavelength-selective element (G) and thereby analyzed, in order, in accordance with the analysis, to adjust the wavelength-selective element or the OPO 2.
摘要:
A pulsed laser comprises an oscillator (10), a laser medium (14), a wavelength selective member (12) for tuning the wavelength of a beam pulse (18) emitted by the oscillator, and means for pulsed excitation of the laser medium (14). The laser medium (14) is excited at least twice at consecutive times to generate a single beam pulse (18).
摘要:
A gas discharge laser includes elongated discharge electrodes having an active surface width that varies along the length of the resonator. In one example each of the electrodes is formed by a row of pins having a circular active surface. The pins are diametrically aligned with the active surfaces generally coplanar.
摘要:
Arcing can be minimized in a discharge chamber of an excimer or molecular fluorine laser system by utilizing an improved electrode structure. An electrode structure can include at least one ceramic spoiler positioned near the discharge region of the electrode. An insulating ceramic spoiler can reduce the effective area over which arcing can occur, and can reduce the likelihood of arcing by improving the flow of gas between the electrodes, such as by allowing for design flexibility and reducing the necessary height of a nose portion used to control the discharge area of the electrode. An improved blower design, which can utilize improved bearings and a dry film lubricant, can help to circulate the laser gas between the electrode structures, such as at a speed of at least 30 m/s in order to operate the laser at repetition rates of 4 kHz or higher.
摘要:
A method and devices for preionizing the main discharge gas volume of a gas discharge laser are described. The method and devices provide a preionizing discharge to the main gas discharge volume from above or below the main gas discharge volume. In combination with a shielding arrangement which reduces the spread of the preionization discharge other than to the main gas discharge volume, the exposure of other laser components and gas volumes to said preionization discharge is thereby minimized.
摘要:
An excimer laser has a laser chamber containing a laser gas and including an electrode assembly for firing gas discharge pulses in the laser gas for pumping the laser. The electrode assembly includes two elongated electrodes, one or both of which is partially covered by a ceramic foam. The electrodes are arranged to provide a discharge gap between the electrodes. The ceramic foam on an electrode serves to damp acoustic disturbances and resulting refractive index disturbances in the gas that occur as a result of firing a gas discharge pulse in the discharge gap.