An outstanding technique in point of ultra-precision as well as economical production of mirrors is Single Point Diamond Turning (SPDT). The unique properties of the diamonds are used to get optical surfaces with roughness values down to 5 nm rms (root mean square) and very precise form accuracy down to 70 nm rms and 500 nm p.-v. (peak to valley) value over an area of 200 mm x 200 mm. This quality level is typical for applications in the Near Infrared (NIR) and Infrared (IR) range. For applications in the VIS and UV range the turning structures must be removed with a smoothing procedure in order to minimize the scatter losses. Favorable is an aluminium base body plated with a thick-film of Nickel-Phosphorus alloy (NiP). This alloy can be polished with computer assistance. Ion Beam Figuring (IBF) is the final manufacturing step. The properties after the finishing process are better than 1 nm rms for roughness and down to 15 nm rms respectively 100 nm p.-v. regarding the surface irregularity for complex optical shapes. The techniques SPDT, polishing and IBF ensures a high quality level for large mirrors with plan, spherical or aspherical surfaces. The manufacturing chain will be analyzed by surface characterisation based on 2D profilometry and white light interferometry to measure the roughness and 3D-profilometry and interferometry to monitor the shape irregularity. Scattering light analysis deepens these investigations. This paper summarizes technologies and measurement results for SPDT and surface finish of metal mirrors for novel optical applications
A new approach for generating long‐distance self‐healing Bessel beams, which is based on a ring‐shaped (annular) lens and a spherical lens in 4f‐configuration, is reported. With this, diffraction‐free light evolution of a zeroth order Bessel beam over several meters is shown and available scaling opportunities that surpass current technologies by far are discussed. Furthermore, it is demonstrated how this setup can be adapted to create Bessel beam superpositions, realizing the longest ever reported optical conveyor beam and helicon beam, respectively. Last, the self‐healing capabilities of the beams are tested against strong opaque and non‐opaque scatterers, which again emphasizes the great potential of this new method.
The requirements for a broadband antireflective structure in the THz spectral region are derived. Optimized structural parameters for a surface-relief grating adapted to the spectrum of an intended THz pulse are deduced. The effect of a structure fabricated into Topas((R)) by a single-point diamond-turning process is demonstrated.
The combination of a 10.6 μm main pulse CO2 laser and a 1064 nm pre-pulse Nd:YAG laser in EUV source concepts for HVM would require collector mirrors with an integrated spectral purity filter that suppresses both laser wavelengths. This paper discusses a new approach of a dual-wavelength spectral purity filter to suppress 10.6 μm and 1064 nm IR radiation at the same time. The dual-wavelength spectral purity filter combines two binary phase gratings that are optimized for 10.6 μm and 1064 nm, respectively. The dual phase grating structure has been realized on spherical sub-aperture EUV collector mirrors having an outer diameter of 150 mm. IR suppression factors of 260 at 10.6 μm and 620 at 1064 nm have been measured on the sub-aperture EUV collector while its EUV reflectance exceeded 64 % at 13.5 nm
By the use of a thin highly oriented pyrolytic graphite crystal (HOPG) bent to a high-performance ellipsoidal shape it was possible to focus monochromatic x-rays of 4.5 keV photon energy with an efficiency of 0.0033, which is 30 times larger than for previously used bent crystals. Isotropic Ti K alpha radiation of a 150 microm source was focused onto a 450 microm spot. The size of the focal spot can be explained by broadening due to the mosaic crystal rocking curve. The rocking curve width (FWHM) of the thin graphite foil was determined to 0.11 degrees. The estimated temporal broadening of an ultrashort K alpha pulse by the crystal is not larger than 300 fs. These properties make the x-ray optic very attractive for ultrafast time-resolved x-ray measurements.
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