Abstract: A method for wavelength tunable output from a broadband spectrum using a quasi phase-matched optical parametric amplifier/difference frequency generator (CQPM OPA/DFG)-based apparatus involves changing the relative timing of a pump pulse with respect to a seed pulse. The temporal variation varies the location of the spatial/temporal overlap of the spectrally narrow pump pulse over the spectrally broad seed spectrum occurring within the CQPM nonlinear medium. This overlap position determines the portion of the seed pulse that is phase-matched as the signal in the OPA or the seed for DFG. Piezo-electric fiber stretchers may be employed to vary the relative pulse timing and enables tuning of the output from the OPA or DFG without the use of any moving parts. Associated apparatus is disclosed.

Abstract: A method for wavelength tunable output from a broadband spectrum using a quasi phase-matched optical parametric amplifier/difference frequency generator (CQPM OPA/DFG)-based apparatus involves changing the relative timing of a pump pulse with respect to a seed pulse. The temporal variation varies the location of the spatial/temporal overlap of the spectrally narrow pump pulse over the spectrally broad seed spectrum occurring within the CQPM nonlinear medium. This overlap position determines the portion of the seed pulse that is phase-matched as the signal in the OPA or the seed for DFG. Piezo-electric fiber stretchers may be employed to vary the relative pulse timing and enables tuning of the output from the OPA or DFG without the use of any moving parts. Associated apparatus is disclosed.

Abstract: In a particular embodiment, a relatively high-energy thulium fiber laser operating at the wavelength ?=2 ?m may be used to selectively modify a front and/or a back surface of silicon and gallium arsenide wafers. The processing regime was studied in terms of the process parameters variation, and the corresponding modification fluence thresholds were determined. The results revealed considerable differences in morphology between front and back surface modifications, and that the back surface modification threshold of Si is significantly higher than at the front surface. Basic analytic modeling and z-scan measurements were performed to study the absorption mechanisms. In a broader embodiment the processing regime is not specifically limited to a thulium fiber laser.

Abstract: A laser system that generates light in the mid-infrared (mid-IR) wavelength range is disclosed. The laser system includes an optical fiber laser having a thulium-doped optical fiber gain medium and that is configured to generate pump light having an optical power of greater than 50 W. The laser system also includes an optical parametric oscillator (OPO) arranged to receive the pump light and configured to generate therefrom, via spontaneous parametric downconversion, mid-IR-wavelength output light. A phase-matching tuning curve is used to select the pump wavelength that provides desired signal and idler wavelengths for the outputted signal and idler light. The laser system is capable of generating high-mode-quality 100 ns optical pulses with about 400 ?J energy at an average power greater than 5 W, in some cases up to several tens of Watts, and in some cases greater than 50 W at the pump wavelength.

Abstract: Plasma discharge sources for generating emissions in the VUV, EUV and X-ray spectral regions. Embodiments can include running a current through liquid jet streams within space to initiate plasma discharges. Additional embodiments can include liquid droplets within the space to initiate plasma discharges. One embodiment can form a substantially cylindrical plasma sheath. Another embodiment can form a substantially conical plasma sheath. Another embodiment can form bright spherical light emission from a cross-over of linear expanding plasmas. All the embodiments can generate light emitting plasmas within a space by applying voltage to electrodes adjacent to the space. All the radiative emissions are characteristic of the materials comprising the liquid jet streams or liquid droplets.

Abstract: Method and apparatus for producing extreme ultra violet (EUV) and soft x-ray radiation from an ultra-low debris plasma source are disclosed. Targets are produced by the free jet expansion of various gases through a temperature controlled nozzle to form molecular clusters. These target clusters are subsequently irradiated with commercially available lasers of moderate intensity (10.sup.11 -10.sup.12 watts/cm.sup.2) to produce a plasma radiating in the region of 0.5 to 100 nanometers. By appropriate adjustment of the experimental conditions the laser focus can be moved 10-30 mm from the nozzle thereby eliminating debris produced by plasma erosion of the nozzle.

Abstract: A multiple arc radiation preionizer for gas lasers formed of a metal electrical conductor with the conductor having formed over a portion of its length, a series of gaps to form a series of intervening discharge electrodes such that on energization of the conductor, a multiplicity of arc discharges is obtained. In a first embodiment the conductor is formed or positioned over the surface of a dielectric sheet such that arcs formed between electrodes are conducted over the surface of the sheet. The discharge electrodes are capacitively connected to ground or the low voltage side of the input via individual low-valued capacitors or by means of a conductor positioned in spaced relation to said electrodes.