Invited Article: Coherent imaging using seeded free-electron laser pulses with variable polarization: First results and research opportunities

F. Capotondi, E. Pedersoli, N. Mahne, R. H. Menk, G. Passos, L. Raimondi, C. Svetina, G. Sandrin, M. Zangrando, M. Kiskinova, S. Bajt, M. Barthelmess, H. Fleckenstein, H. N. Chapman, J. Schulz, J. Bach, R. Frömter, S. Schleitzer, L. Müller, C. Gutt, and G. Grübel

FERMI@Elettra, the first vacuum ultraviolet and soft X-ray free-electron laser (FEL) using by default a “seeded” scheme, became operational in 2011 and has been opened to users since December 2012. The parameters of the seeded FERMI FEL pulses and, in particular, the superior control of emitted radiation in terms of spectral purity and stability meet the stringent requirements for single-shot and resonant coherent diffraction imaging (CDI) experiments. The advantages of the intense seeded FERMI pulses with variable polarization have been demonstrated with the first experiments performed using the multipurpose experimental station operated at the diffraction and projection imaging (DiProI) beamline.

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Rev. Sci. Instrum. 84, 051301 (2013)

Simultaneous immersion Mirau interferometry

Oleksandra V. Lyulko, Gerhard Randers-Pehrson, and David J. Brenner

A novel technique for label-free imaging of live biological cells in aqueous medium that is insensitive to ambient vibrations is presented. This technique is a spin-off from previously developed immersion Mirau interferometry.

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Rev. Sci. Instrum. 84, 053701 (2013)

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

Li Chen, Hirokazu Ueta, Régis Bisson, and Rainer D. Beck

We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS).

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Rev. Sci. Instrum. 84, 053902 (2013)

Theoretical and experimental study on two-stage-imaging microscopy using ellipsometric contrast for real-time visualization of molecularly thin films

Y. Kajihara, K. Fukuzawa, S. Itoh, R. Watanabe, and H. Zhang

A two-stage-imaging ellipsometric-contrast microscope (TIEM) has been developed to measure the distribution of film thickness over a wide area of molecularly thin liquid films with a high lateral resolution, wide field of view, high thickness resolution, and high-speed. Moreover, this ellipsometric microscope enables us to achieve simultaneous measurements with other measurement apparatuses.

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Rev. Sci. Instrum. 84, 053704 (2013)

Capacitive readout and gating of superconducting single photon detectors

Hatim Azzouz, Reinier W. Heeres, Sander N. Dorenbos, Raymond N. Schouten, and Valery Zwiller

We propose and develop a readout scheme for superconducting single-photon detectors based on an integrated circuit, relaxing the need for large bandwidth amplification and resulting in voltage steps proportional to the number of detected photons. We also demonstrate time gating, to filter scattered light in time and reduce dark counts. This could lead to a higher signal-to-noise ratio.

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Rev. Sci. Instrum. 84, 053108 (2013)

A high-speed magnetic tweezer beyond 10,000 frames per second

Bob M. Lansdorp, Shawn J. Tabrizi, Andrew Dittmore, and Omar A. Saleh

The magnetic tweezer is a single-molecule instrument that can apply a constant force to a biomolecule over a range of extensions, and is therefore an ideal tool to study biomolecules and their interactions. However, the video-based tracking inherent to most magnetic single-molecule instruments has traditionally limited the instrumental resolution to a few nanometers, above the length scale of single DNA base-pairs. Here we have introduced superluminescent diode illumination and high-speed camera detection to the magnetic tweezer, with graphics processing unit-accelerated particle tracking for high-speed analysis of video files. (Click on the link to read more).

Rev. Sci. Instrum. 84, 044301 (2013)

Flow bioreactor design for quantitative measurements over endothelial cells using micro-particle image velocimetry

Chia Min Leong, Abram Voorhees, Gary B. Nackman, and Timothy Wei

Mechanotransduction in endothelial cells (ECs) is a highly complex process through which cells respond to changes in hemodynamic loading by generating biochemical signals involving gene and protein expression. To study the effects of mechanical loading on ECs in a controlled fashion, different in vitro devices have been designed to simulate or replicate various aspects of these physiological phenomena. This paper describes the design, use, and validation of a flow chamber which allows for spatially and temporally resolved micro-particle image velocimetry measurements of endothelial surface topography and stresses over living ECs immersed in pulsatile flow.(Click on the link to read more).

Rev. Sci. Instrum. 84, 045109 (2013)