RESUMEN
We have demonstrated stable and self-sustaining Kerr-lens mode locking of a Cr:LiSGAF laser pumped by AlGaInP laser diodes. A hard aperture near one end of the laser provides the necessary amplitude modulation. This allsolid- state system generates transform-limited 100-fs pulses, tunable from 810 to 860 nm. The average power at 830 nm is 35 mW, with fluctuations of much less than 1%. The thermal properties of Cr:LiSGAF will permit scaling of these results to higher power.
RESUMEN
The propagation of high-peak-power (>10-kW) sub-100-fs pulses near the zero-dispersion wavelength of an optical fiber was studied experimentally. Four-photon mixing and stimulated Raman scattering were observed for fiber lengths greater than 2 m. With pulses as short as 25 fs, four-photon mixing dominates, resulting in efficient conversion of the input pulse spectrum into two coherent spectral bands. This can be used to extend the useful wavelength range of femtosecond lasers in the infrared.
RESUMEN
The use of a resonant cavity for efficient second-harmonic generation with 100-fs pulses is demonstrated. With 2-nJ pulses from a mode-locked Cr:forsterite laser, 53% conversion efficiency to the second harmonic at 625 nm is achieved while ~100-fs duration is maintained. This is an order-of-magnitude improvement over the conversion efficiency obtained directly with the laser output.
RESUMEN
Laser plasmas are intrinsically an attractive soft-x-ray source for projection lithography. Compact, flexible, and small enough to be dedicated to a single installation, they offer an alternative to costly multi-installation synchrotron sources. For laser plasmas to provide ideal sources of soft x rays for projection lithography, their properties must be tuned to optimize several critical parameters. High x-ray conversion in the spectral band relevant to projection lithography is obviously required and has already received the attention of several studies. However, other features, such as the spectral content and direction of the x-ray emission, the plasma and particulate emission, the technology of the target, and efficient laser design, must also be optimized. No systematic study of all these features specifically for projection lithography has yet been made. It is our purpose to optimize these parameters in a coordinated approach, which leads to the design of a source that satisfies all the demanding requirements of an operating lithographic installation. We make an initial investigation of the plasma and particle emission of plasmas that have previously been shown to be good x-ray converters to the 13-nm band. The importance of the results reported may well force new approaches to the design of laser plasma soft-x-ray sources for projection lithography.