Fast miniature plasma focus (FMPF-3), a low energy (235 J) device, is an attractive option for being a
potential source for soft X-ray (SXR) (0.9 – 1.6 keV) lithography due to its smaller X-ray generation spot
size and the capability of being a high repetition source. As a continuation of our work on the enhancement
of SXR emission from this device, in present investigation the insulator sleeve length is optimized for
efficient SXR emission. It plays a major role in the current sheath formation, which is determinant of the
efficient compression and the consequent radiation emission. The influence of the presence or absence of
cathode rods on the SXR emission is also investigated. It is one least explored parameter although it plays a
major role in the determination of plasma sheath curvature which in turn influences the dynamic plasma
inductance and the magnetic flux associated with moving current sheath. Another major highlight of this
study is the time resolved laser shadowgraphy of the plasma sheath dynamics to understand the influence of
the variation of these parameters on it. Through optimization of the insulator sleeve length, the highest ever
obtained SXR yield of 1.8 J/shot was achieved for this device.
Fourier transform interferometry is commonly performed by means of mechanically scanning interferometers such as a
Michelson and characterized by one scanning mirror. This results in severe limitations of the capability of measuring fast
signals. To overcome this drawback, we present a multi-channel FTIR spectrometer (MC-FTIR) that is capable of single-shot
operation no matter how short the single pulse is, provided it delivers sufficient photons for the signal to exceed the
noise. It can capture fast transient signals, limited by the signal-to-noise ratio and data transfer rate of the detector. Our
device is based on a micro/nanomanufactured 3D multimirror array (MMA) which allows collecting a whole
interferogram simultaneously. MMAs are manufactured by means of a patented multiple moving mask grey-level deep
X-ray lithography process. Up to 640 mirror cells, generating optical path differences from 0 to about 1 mm, were
achieved so far at optical quality. We have demonstrated sub-millisecond pulses and a theoretical spectral resolution of
10 cm<sup>-1</sup> in the mid-IR. The optical system is similar to a Czerny-Turner mount with the MMA replacing the grating and
an MCT focal plane array (FPA) capturing the interferogram.
Our MC-FTIR enables extension of FTIR-based IR spectroscopy to arbitrarily short pulses and to fast transient signals.
As the optical system is small and rugged, the instrument lends itself readily to field applications. Ongoing work is
aimed at emerging applications including biomedical, laser-induced breakdown spectroscopy, and spectroscopy of
We present a Fourier transform interferometer that is capable to record single short pulses and fast continuous transient
spectra. This is achieved by spatially parallel instead of time serial processing by means of a micro/nanomanufactured
multimirror array and a pixellated detector camera. The multimirror array is produced in excellent optical quality from
poly(methyl methacrylate) by means of deep X-ray gray level lithography including multiple moving masks followed by
sputter deposition of the gold reflecting surfaces. The crucial components such as the multimirror array and the
pixellated camera are part of a straightforward optical system similar to a Czerny-Turner mount. Results demonstrate
single shot measurements down to 320 μs, only limited by the camera shutter and the infrared source, and the time
evolution of the absorption spectrum of an evaporating acetone layer that shows spectral changes during the first few
seconds. While the spectral range of the multichannel Fourier transform interferometer (MC FTIR) as reported extends
from near to mid infrared, multimirror arrays can be produced for spectra from visible to far infrared. Thus, the potential
performance depends mostly on availability of detectors. The minimum pulse duration is determined by that photon
number in the pulse which yields a sufficient signal to noise ratio, whereas the maximum acquisition rate of continuous
transients is given by the frame rate of the detector.
Meta-foils are all-metal free-standing electromagnetic metamaterials based on interconnected S-string architecture. They
provide a versatile applications' platform. Lacking any substrate or embedding matrix, they feature arrays of parallel
upright S-strings with each string longitudinally shifted by half an S compared to its neighbour to form capacitance-inductance
loops. Geometric parameters include length a, width b, thickness t, and height h of an S, the gap between
adjacent S-strings d, and the periodicity p of the interconnecting lines. Equidistant strings at p=1 form a 1SE meta-foil.
Grouped in pairs of gap d, exhibiting a gap d<sub>p</sub> between pairs, they are named 2SP. Geometric parameters a, b, t, h, d, d<sub>p</sub>,
pS(E or P) and materials' properties like electric conductivity, Young's modulus, thermal expansion coefficient, and heat
capacity determine the electromagnetic, mechanical, and thermal properties of meta-foils including the spectral
dependence of resonance frequencies, refractive index, transmission, reflection, and bending. We show how the
frequency and transmission of left-handed pass-bands depend on a, p, and d<sub>p</sub>, the pSP geometry exhibiting higher
resonance frequency and transmission. Equivalent circuit considerations serve to explain physical reasons. We also
demonstrate mechanical behavior versus p and d<sub>p</sub> justifying the design of a cylindrical hyperlens depending on bent
Ideal metamaterials would consist of metal conductors only that are necessary for negative ε and μ. However, most of
present-day metamaterials include dielectrics for various support functions. Overcoming dielectrics, we manufactured
free-standing THz metamaterials as bi-layer chips of S-string arrays suspended by window-frames at a small gap that
controls the resonance frequency. Remaining problems concerning their useful range of incidence angles and the
possibility of stacking have been solved by manufacturing the first self-supported free-standing all-metal metamaterials
featuring upright S-strings interconnected by metal rods. Large-area slabs show maximum magnetic coupling at normal
incidence with left-handed resonances between 3.2 - 4.0 THz. Such metamaterials which we dub the meta-foil represent
an ideal platform for including index-gradient optics to achieve optical functionalities like beam deflection and imaging.
Micro/nanomanufactured electromagnetic metamaterials in the THz spectral range may help extending the use of
metamaterials in transportation. S-string based THz metamaterials as manufactured by SSLS, in particular, the meta-foil,
provide a promising platform for applications. Special emphasis may be given to antennas being conformal or quickly
steerable or tunable for inter-traffic communication. Achievements by SSLS in co-operation with MIT and Zhejiang
University are discussed and potential applications outlined.
X-ray phase-contrast tomographic microimaging is a powerful tool to reveal the internal structure of opaque soft-matter objects that are not easily seen in standard absorption contrast. In such low Z materials, the phase shift of X-rays transmitted can be important as compared to the absorption. An easy experimental set up that exploits refractive contrast formation can deliver images that are providing detailed structural information. Applications are abundant in fields
including polymer science and engineering, biology, biomedical engineering, life sciences, zoology, water treatment and filtration, membrane science, and micro/nanomanufacturing. However, available software for absorptive contrast tomography cannot be simply used for structure retrieval as the contrast forming effect is different. In response, CSIRO has developed a reconstruction code for phase-contrast imaging. Here, we present a quantitative comparison of a micro phantom manufactured at SSLS with the object reconstructed by the code using X-ray images taken at SSLS. The phantom is a 500 μm thick 800 μm diameter cylindrical disk of SU-8 resist having various eccentric cylindrical bores with diameters ranging from 350 μm to 40 μm. Comparison of these parameters that are well known from design and post-manufacturing measurements with reconstructed ones gives encouraging results.
Up to date, electromagnetic metamaterials (EM<sub>3</sub>) have been mostly fabricated by primary pattern generation via electron beam or laser writer. Such an approach is time-consuming and may have limitations of the area filled with structures.
Especially, electron beam written structures are typically confined to areas of a few 100×100 μm<sup>2</sup>. However, for meaningful technological applications, larger quantities of good quality materials are needed. Lithography, in particular X-ray deep lithography, is well suited to accomplish this task. Singapore Synchrotron Light Source (SSLS) has been applying its LIGA process that includes primary pattern generation via electron beam or laser writer, X-ray deep
lithography and electroplating to the micro/nano-manufacturing of high-aspect ratio structures to produce a variety of EM<sup>3</sup> structures. Starting with Pendry's split ring resonators, we have pursued structure designs suitable for planar lithography since 2002 covering a range of resonance frequencies from 1 to 216 THz. More recently, string-like structures have also been included. Latest progress made in the manufacturing and characterization of quasi 3D
metamaterials having either split ring or string structures over areas of about ≈1 cm<sup>2</sup> extension will be described.