Shanghai Tech University has chosen Inprentus to provide a diffraction grating for the Shanghai Soft X-ray Free-Electron Laser (SSXFEL), the first X-ray free-electron laser user facility in China. Inprentus was selected for its unique capability to manufacture a blazed diffraction grating with varied line spacing (VLS) on a cylindrical, concave substrate. The grating will be one of the core elements used in the diagnostic spectrometer to provide high spectral resolution photon diagnostics of the FEL-II beamline.
Pictured: Inprentus blazed grating. Inprentus specializes in providing ultra-low blaze-angle, varied line spacing, diffraction gratings for Synchrotron and Free-Electron Laser (FEL) facilities.
The Inprentus grating will facilitate the important goal of high spectral resolution (R>40,000) across a broad photon energy range of 0.4keV-1.2keV. “A high precision optical element is very important to realize this goal, especially a variable line spacing grating” says Dr. Ximing Zhang, a scientist working with Dr. Bin Li on the facility design. He further added that this grating has been designed to be created on a meridian cylindrical surface to control and optimize the spectrometer’s meridian focal spot, achieving higher sensitivity. Dr. Zhang explained that “during the commissioning of the FEL facility and the undulator, especially when the light is far from saturation, the spectrometer’s higher-resolution and suppressed sagittal astigmatism will greatly enhance the detection efficiency.”
FELs such as the Shanghai Soft X-ray Free-Electron Laser (SSXFEL) have many unique advantages as photon sources, including ultrashort pulses, wavelength tunability, high brightness and peak power, and wide spectral range. Diffractive optics are especially essential to leveraging the wide spectral range in experiments requiring narrow bandwidths. The high brightness of the FEL provides a challenge as well as a benefit: serious radiation damage can occur on the grating’s coating materials if the groove profile has a lateral surface. Importantly, with low-blaze angle gratings such as the grating provided by Inprentus, the grazing-incidence light maintains a low footprint on the groove surface, reducing thermal effects and minimizing radiation damage. Blazed gratings are therefore optimal for use in FELs for their design reliability and applicability as well as higher efficiency than other types of gratings. Inprentus is the world leader in low-blaze angle diffraction gratings for synchrotron and FEL applications, previously achieving blaze angles as low as 0.1 degrees using the fabrication technique of mechanical ruling.
The SSXFEL facility was developed on the campus of the Shanghai Synchrotron Radiation Facility (SSRF) to promote free-electron laser research in China and to explore possibilities for seeding X-ray FELs. The facility specializes in coherent diffraction imaging, ultra-fast physics, pump probe, and other experiments to study atomic processes using soft X-rays within the “water window”, the wavelength range (2.3 – 4.4nm) where water is relatively transparent, while other materials, notably carbon, are opaque. Fundamental processes in materials science and biology can be more easily studied at this wavelength range.
Subha Kumar — Chief Growth Officer of Inprentus — says "Inprentus has been awarded this custom grating project due to the technical complexity as well as the project complexity. In addition to efficiency and resolving-power targets related to manufacturing, Inprentus will also coordinate the procurement of precisely shaped substrates and a thin, platinum overcoat for the finished grating. Inprentus scientists have experience with managing the complex requirements for FEL grating solutions, allowing us to assure timely delivery of high-quality gratings within budget.”
Inprentus Inc.
Inprentus designs, manufactures, and sells X-ray and EUV diffraction gratings for synchrotron radiation facilities. These state-of-the-art gratings are used for a variety of scientific and commercial applications by many Fortune 500 companies, academic institutions, and government laboratories around the world. Inprentus was founded in 2012 to commercialize an innovative, nano-scale lithography technology using mechanical deformation of metallic surfaces.
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