Quasi-supercontinuum source in the extreme ultraviolet using multiple frequency combs from high-harmonic generation.
Quasi-supercontinuum source in the extreme ultraviolet using multiple frequency combs from high-harmonic generation.
复制标题
使用高次谐波产生的多个频率梳的极紫外准超连续谱源。
作者：
M. Wünsche;S. Fuchs;Stefan Aull;J. Nathanael;M. Möller;C. Rödel;G. Paulus
利用台式飞秒激光器和可调谐光学参量放大器（OPA）作为高次谐波产生（HHG）的驱动器，实现了极紫外（XUV）准超连续谱光源。谐波辐射通常是基频的奇数倍梳状，由来自OPA的近红外（NIR）激光脉冲产生。在30至100 eV范围内的准连续XUV光谱是通过对具有略微不同的基频的多个谐波梳状光谱进行平均来实现的，因此各个谐波之间的光谱间距不同。驱动激光波长在平均时间段期间自动扫描。在30 - 100 eV范围内，准超连续谱XUV光源的总光子通量为4×109光子/s，在100 - 200 eV范围内，准超连续谱XUV光源的总光子通量为1× 107光子/s，适合于XUV相干层析成像（XCT）或近边吸收精细结构光谱（NEXAFS）等应用。
A quasi-supercontinuum source in the extreme ultraviolet (XUV) is demonstrated using a table-top femtosecond laser and a tunable optical parametric amplifier (OPA) as a driver for high-harmonic generation (HHG). The harmonic radiation, which is usually a comb of odd multiples of the fundamental frequency, is generated by near-infrared (NIR) laser pulses from the OPA. A quasi-continuous XUV spectrum in the range of 30 to 100 eV is realized by averaging over multiple harmonic comb spectra with slightly different fundamental frequencies and thus different spectral spacing between the individual harmonics. The driving laser wavelength is swept automatically during an averaging time period. With a total photon flux of 4×109 photons/s in the range of 30 eV to 100 eV and 1×107photons/s in the range of 100 eV to 200 eV, the resulting quasi-supercontinuum XUV source is suited for applications such as XUV coherence tomography (XCT) or near-edge absorption fine structure spectroscopy (NEXAFS).