We have created a broad spectrum spanning more than an optical octave by launching femtosecond pulses from a battery operated Cr:LiSAF laser into a photonic crystal fiber. Despite the massive broadening in the fiber, the comb structure of the spectrum is preserved, and this frequency comb is perfectly suited for applications in optical frequency metrology.
Reflection curves of bent crystals were calculated using the Takagi-Taupin theory of dependence on bending radius, wavelength, crystal thickness and Bragg angle. The reflection properties of bent crystals were measured for bending radii down to 90 mm. Usually, for the measurement of rocking curves of crystals with large bending radii, the double-crystal diffractometer was used in parallel position (n,-n). A special achromatic diffractometer consisting of a plane and a bent crystal is proposed. It is used to measure rocking curves of bent crystals with small bending radii (R < l m). Experimental values show close agreement with the theory. The reflection properties are important for X-ray microscopy with two-dimensionally bent crystals and for X-ray spectroscopy with bent crystals.
X-ray spectroscopical and microscopical methods are used for the determination of the spectral and spatial distribution of X-ray intensity of laser-produced plasmas. The use of Bragg reflections of two-dimensionally bent crystals enables the X-ray microscopical imaging in narrow spectral ranges (AX/X = 10~4 to 10~2) with wavelengths 0.1 nm < X < 2.6 nm. It is possible to adapt, in the X-ray microscope, the distances, magnification, position, and width of the spectral window to the special conditions of the laser facility. Manufacturing and testing of the two-dimensionally bent crystals requires a great deal of effort. It was demonstrated that a spatial resolution of about 5 /xm was achieved, and that the experimentally determined reflectivity was found to be in close agreement with the dynamical theory of X-ray interferences. Due to high luminosity of the X-ray microscope, in experiments with laser-produced plasmas it was necessary to attenuate the radiation with aperture-limiting diaphragms or filters down to 0.01-1% of the original intensity in the case of a magnification of about one. Emission of the resonance line W 1-2, the intercombination line of helium-like ions, and Lyman alpha line were imaged simultaneously with a three-channel microscope. Such images form the foundation for establishing the 7V e (r), T z (r) maps.
In the paper we report about the progress made at XTREME technologies in the development of EUV sources based on gas discharge produced plasma (GDPP) technologies and laser produced plasma (LPP) technologies.First prototype xenon GDPP sources of the type XTS 13-35 based on the Z-pinch principle with 35 W power in 2π sr have been integrated into micro-exposure tools from Exitech, UK. Specifications of the EUV sources and experience of integration as well as data about component and optics lifetime are presented.In the source development program for Beta exposure tools and high volume manufacturing exposure tools both tin and xenon have been investigated as fuel for the EUV sources. Development progress in porous metal cooling technology as well as pulsed power circuit design has led to GDPP sources with xenon fuel continuous operating with an output power of 200 W in 2π sr at 4500 Hz repetition rate. With tin fuel an output power of 400 W in 2π sr was obtained leaving all other conditions unaltered with respect to the xenon based source. The performance of the xenon fueled sources is sufficiently good to fulfill all requirements up to the beta tool level.For both the xenon and the tin GDPP sources detailed data about source performance are reported, including component lifetime and optics lifetime. The status of the integration of the sources with grazing incidence collector optics is discussed. Theoretical estimations of collection efficiencies are compared with experimental data to determine the loss mechanisms in the beam path. Specifically contamination issues related to tin as target material as well as debris mitigation in tin sources is addressed.As driver lasers for the LPP source research diode-pumped Nd:YAG lasers have been used to generate EUV emitting plasma. As target material xenon has been employed. Conversion efficiencies have been measured and currently the maximum conversion efficiency amounts to 1 %. The laser driver power of 1.2 kW is currently achieved with a masteroscillator power-amplifier industrial Nd:YAG laser configuration. With this laser, xenon based EUV sources have achieved 10 W EUV power at 13.5 nm emitted into 2π sr solid angle.For the xenon LPP sources detailed data about the achieved source performance including component lifetime and optics lifetime are reported. The status of the integration of the sources with normal incidence collector optics is shown.The potentials and limits of Z-pinch GDPP and LPP EUV source technologies to achieve high volume manufacturing specifications are discussed in this paper.
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