Mechanically ruled aberration-corrected concave gratings for a flat-field grazing-incidence spectrograph.
About: This article is published in Applied Optics.The article was published on 1983-02-15. It has received 281 citations till now. The article focuses on the topics: Spectrograph.
Citations
More filters
TL;DR: In this paper, the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured.
Abstract: We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 J for individual pulses, and the average energy per pulse reached 70 J. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per second, the average extreme-ultraviolet power reached 20 mW. The output beam also contained a significant contribution from odd harmonics of approximately 0.6% and 0.03% for the 3rd (4.6 nm) and the 5th (2.75 nm) harmonics, respectively. At 2.75 nm the 5th harmonic of the radiation reaches deep into the water window, a wavelength range that is crucially important for the investigation of biological samples.
1,390 citations
Cites methods from "Mechanically ruled aberration-corre..."
...The third monochromator was a flat field system, equipped with a Harada grating [41] but with a highly sensitive back illuminated CCD camera (Andor Technology) containing 2048×512 pixels, each with a footprint of 13×13 microns squared....
[...]
TL;DR: In this article, the first experimental demonstration of high harmonic generation in the relativistic limit was obtained on the Vulcan Petawatt laser, achieving high conversion efficiencies (η>10−6 per harmonic) and bright emission (>1022 photons s−1 mm−2 mrad−2 (0.1% bandwidth)) at wavelengths <4nm.
Abstract: The generation of extremely bright coherent X-ray pulses in the femtosecond and attosecond regime is currently one of the most exciting frontiers of physics–allowing, for the first time, measurements with unprecedented temporal resolution1,2,3,4,5,6. Harmonics from laser–solid target interactions have been identified as a means of achieving fields as high as the Schwinger limit2,7 (E=1.3×1016 V m−1) and as a highly promising route to high-efficiency attosecond (10−18 s) pulses8 owing to their intrinsically phase-locked nature. The key steps to attain these goals are achieving high conversion efficiencies and a slow decay of harmonic efficiency to high orders by driving harmonic production to the relativistic limit1. Here we present the first experimental demonstration of high harmonic generation in the relativistic limit, obtained on the Vulcan Petawatt laser9. High conversion efficiencies (η>10−6 per harmonic) and bright emission (>1022 photons s−1 mm−2 mrad−2 (0.1% bandwidth)) are observed at wavelengths <4 nm (the `water-window' region of particular interest for bio-microscopy).
431 citations
TL;DR: A new type of grazing-incidence spectrometer with a flat focal field is developed, and XUV spectroscopy in the extreme ultraviolet region ranging from 15 to 200 A is carried out, showing the importance of the transient treatment of picosecond laser-produced plasmas.
Abstract: A new type of grazing-incidence spectrometer with a flat focal field is developed, and XUV spectroscopy in the extreme ultraviolet region ranging from 15 to 200 A is carried out. Soft x-ray line spectra emitted from picosecond laser plasmas of aluminum and iron targets are measured and good resolutions are obtained in the XUV region. The spectral regions of detection are extended to shorter wavelengths (15 A) using a finer spaced grating. Computational studies on x-ray spectra are also performed taking into account the transient characteristics of picosecond laser-produced plasmas; the importance of the transient treatment is clearly shown. This type of soft x-ray spectrometer should be useful for time-resolved picosecond soft x-ray spectroscopy.
156 citations
TL;DR: The results of an experiment measuring the photoabsorption in the spectral region from 50 to 120 eV of x-ray-heated iron are reported which corroborate these new opacity calculations, providing an indirect validation of the theory.
Abstract: Novel opacity calculations, which treat in detail the spectra of medium-Z ions [Rogers and Iglesias, Astrophys. J. Suppl. Ser. 79, 507 (1992)], produce results that are substantially different from opacity calculations extant in the literature. These new opacities provide solutions to a number of outstanding problems in astrophysics, thus providing an indirect validation of the theory. We report the results of an experiment measuring the photoabsorption in the spectral region from 50 to 120 eV of x-ray-heated iron which corroborate these new opacity calculations.
134 citations
TL;DR: An account is given of a fundamentally different approach to the use of variable line-space gratings for grazing incidence spectrometers, which results in small aberrations over a wide instantaneous range in wavelength.
Abstract: An account is given of a fundamentally different approach to the use of variable line-space gratings for grazing incidence spectrometers. In the new approach, the gratings are flat and they are placed to intercept the converging beam from a collecting mirror rather than the diverging beam from a slit. This results in (1) small aberrations over a wide instantaneous range in wavelength, (2) a modest required variation in line spacing across the ruled width, (3) a simultaneous minimization of both the spectral and image height aberrations, and (4) a completely stigmatic zero order image. The slitless arrangement common to these designs is very compact, having no additional length behind the focal plane of the collecting mirror. In-plane and conical fan designs are considered. One combination design, in the form of an echelle spectrometer, is discussed. The designs are considered to represent ideal candidates for moderate to high resolution spectrometers on such missions as the Far Ultraviolet Spectroscopic Explorer (FUSE, now Columbus) and the Advanced X-ray Astrophysics Facility (AXAF).
134 citations
References
More filters
TL;DR: A highly efficient visible-UV monochromator and a coma-type aberration-reduced Seya-Namioka monochromaator have been designed and fabricated using mechanically ruled aberration -corrected concave gratings.
Abstract: Aberration-corrected concave gratings with curved and variable spacing grooves are ruled with a numerically controlled ruling engine. In the design of aberration-corrected concave gratings, mechanical methods allow more freedom to choose the amount of space variation than do holographic methods. A highly efficient visible–UV monochromator and a coma-type aberration-reduced Seya-Namioka monochromator have been designed and fabricated using mechanically ruled aberration-corrected concave gratings. The gratings can be used with VUV monochromators and spectrographs with improved image focusing properties.
253 citations
TL;DR: A compact vacuum ultraviolet spectrometer system has been developed to provide time-resolved impurity spectra from tokamak plasmas and its sensitivity is comparable with that of a conventional grazing-incidence monochromator.
Abstract: A compact vacuum ultraviolet spectrometer system has been developed to provide time-resolved impurity spectra from tokamak plasmas. Two interchangeable aberration-corrected toroidal diffraction gratings with flat focal fields provide simultaneous coverage over the ranges 100–1100 A or 160–1700 A. The detector is an intensified self-scanning photodiode array. Spectral resolution is 2 A with the higher dispersion grating. Minimum readout time for a full spectrum is 20 msec, but up to seven individual spectral lines can be measured with a 1-msec time resolution. The sensitivity of the system is comparable with that of a conventional grazing-incidence monochromator.
186 citations