We report on a compact, desktop size, laboratory type microscopy setup, based on a short wavelength gas puff target soft X-ray source, which emits incoherent radiation in “water-window” spectral range. The microscope employs a Wolter type I reflective objective and allows capturing magnified images of objects with ~1-μm spatial resolution and exposure time as low as 5 s. A detailed characterization and optimization of both the source and the microscope setups are presented and discussed.
1 September 2013 in Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
A comparative study of photoionized plasmas created by two soft X-ray and extreme ultraviolet (SXR/EUV) laser plasma sources with different parameters is presented. The two sources are based on double-stream Xe/He gas-puff targets irradiated with high (500 J/0.3 ns) and low energy (10 J/1 ns) laser pulses. In both cases, the SXR/EUV beam irradiated the gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Irradiation of gases resulted in formation of photoionized plasmas emitting radiation in the SXR/EUV range. The measured Ne plasma radiation spectra are dominated by emission lines corresponding to radiative transitions in singly charged ions. A significant difference concerns origin of the lines: K-shell or L-shell emissions occur in case of the high and low energy irradiating system, respectively. In high energy system, the electron density measurements were also performed by laser interferometry, employing a femtosecond laser system. A maximum electron density for Ne plasma reached the value of 2·1018 cm−3. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.
A compact, desktop size microscope, based on laser-plasma source and equipped with reflective condenser and diffractive Fresnel zone plate objective, operating in the extreme ultraviolet (EUV) region at the wavelength of 13.8 nm, was developed. The microscope is capable of capturing magnified images of objects with 95-nm full-pitch spatial resolution (48 nm 25–75% KE) and exposure time as low as a few seconds, combining reasonable acquisition conditions with stand-alone desktop footprint. Such EUV microscope can be regarded as a complementary imaging tool to already existing, well-established ones. Details about the microscope, characterization, resolution estimation and real sample images are presented and discussed.
We report on a very compact desk-top transmission extreme ultraviolet (EUV) microscope based on a laser-plasma source with a double stream gas-puff target, capable of acquiring magnified images of objects with a spatial (half-pitch) resolution of sub-50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi-monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy. Developments in nanoscience demand tools capable of capturing images with a nanometer spatial resolution beyond the capability of well-known visible light microscopes. Herein, we present the design details, development, characterization and optimization of a very compact desk-top transmission microscope, operating in invisible to an eye radiation from the so called extreme ultraviolet (EUV) range. The apparatus is based on a laser-plasma source coupled with a special type of objective called Fresnel zone plate. It is capable of acquiring magnified images of objects with a spatial resolution of sub-50 nm, approximately 5–10 times better than the spatial resolution of classical visible light microscopes, in a short acquisition time. The main motivation for development of such compact systems operating with EUV radiations is the possibility to get information about thin samples due to the easily absorption of these radiation by solid materials with very small thicknesses, of the order of about 100 nm. Additionally, the employment of such kind of microscopes might open the possibility to perform experiments without necessity to employ large ‘photon facilities’ such as synchrotrons or free electron lasers and could have a huge impact on the speed of nanotechnology development. Imaging results, concerning nanostructures and biomedical samples, are presented and discussed.