Biological Applications of Short Wavelength Microscopy Based on Compact, Laser-Produced Gas-Puff Plasma Source

Abstract

Over the last decades, remarkable efforts have been made to improve the resolution in photon-based microscopes. The employment of compact sources based on table-top laser-produced soft X-ray (SXR) in the “water window” spectral range (λ = 2.3–4.4 nm) and extreme ultraviolet (EUV) plasma allowed to overcome the limitations imposed by large facilities, such as synchrotrons and X-ray free electron lasers (XFEL), because of their high complexity, costs, and limited user access. A laser-plasma double stream gas-puff target source represents a powerful tool for microscopy operating in transmission mode, significantly improving the spatial resolution into the nanometric scale, comparing to the traditional visible light (optical) microscopes. Such an approach allows generating the plasma efficiently, without debris, providing a high flux of EUV and SXR photons. In this review, we present the development and optimization of desktop imaging systems: a EUV and an SXR full field microscope, allowing to achieve a sub-50 nm spatial resolution with short exposure time and an SXR contact microscope, capable to resolve internal structures in a thin layer of sensitive photoresist. Details about the source, as well as imaging results for biological applications, will be presented and discussed.

UV and soft x-ray emission from gaseous and solid targets employing SiC detectors

“…The laser pulse was focused in the vacuum chamber, where the samples are placed. The employment of a doublestream gas-puff target source, described in detail in [10], allows one to increase the gas density along the emission direction. Such a source is formed by two circularly concentric nozzles.…”

SiC and Ion collectors as diagnostics of laser-generated plasma at intensity of 1010W/cm2

“…A special attention is given to UV and soft X-ray emission and to the measure of the plasma accelerated ions [2][3][4][5]. The employment of UV and X-rays, in fact, finds application in microscopy and biological investigations [6,7], while low energy ions can be employed for thin film deposition and ion sources, for accelerators [8,9]. For this purpose, some of the multiple advantages to employ SiC detectors for plasma diagnostics consist on the SiC gap of 3.2 eV, in the possibility to use such Schottky diode detector at room temperature and higher temperatures.…”

SiC, Si and diamond detectors for comparison of laser-generated plasma in TNSA regime

“…In fact, employing high intensity lasers, above 10 16 W/cm 2 , it is possible to accelerate ions above 1 MeV per charge state, going up to about 100 MeV of protons for hadrontherapy and cell culture irradiation. It is also possible to accelerate protons and deuterons to induce nuclear fusion processes, light ions for implantation in materials, ions and helium for surface analysis, such as to induce characteristics X-ray fluorescence emission for surface analysis and X-ray microscopy [2]- [6].…”