scholarly journals Mid-infrared suspended waveguide platform and building blocks

2019 ◽  
Vol 13 (2) ◽  
pp. 55-61 ◽  
Author(s):  
Alejandro Sánchez-Postigo ◽  
Juan Gonzalo Wangüemert-Pérez ◽  
Jordi Soler Penadés ◽  
Alejandro Ortega-Moñux ◽  
Milos Nedeljkovic ◽  
...  
Keyword(s):  
Building Blocks ◽  
Mid Infrared

Tin diselenide van der Waals materials as new candidates for mid-infrared waveguide chips

Nanoscale ◽  
2019 ◽  
Vol 11 (30) ◽  
pp. 14113-14117 ◽  
Author(s):  
Mengfei Xue ◽  
Qi Zheng ◽  
Runkun Chen ◽  
Lihong Bao ◽  
Shixuan Du ◽  
...  
Keyword(s):  
Near Field ◽  
Van Der Waals ◽  
Building Blocks ◽  
Two Dimensional ◽  
Mid Infrared ◽  
Near Field Imaging ◽  
Van Der Waals Materials ◽  
Field Imaging

Near-field imaging of mid-infrared waveguide in SnSe2 slabs promotes two-dimensional van der Waals materials as building blocks for integrated MIR chips.

scholarly journals Cosmic biology in perspective

2019 ◽  
Vol 364 (11) ◽  
Author(s):  
N. C. Wickramasinghe ◽  
Dayal T. Wickramasinghe ◽  
Christopher A. Tout ◽  
John C. Lattanzio ◽  
Edward J. Steele
Keyword(s):  
Infrared Spectra ◽  
Building Blocks ◽  
Mid Infrared ◽  
Interstellar Clouds ◽  
Astronomical Observations ◽  
Habitable Planets ◽  
Biologically Relevant ◽  
The Galaxy ◽  
Terrestrial Life ◽  
Biologically Relevant Molecules

AbstractA series of astronomical observations obtained over the period 1986 to 2018 supports the idea that life is a cosmic rather than a purely terrestrial or planetary phenomenon. These include (1) the detection of biologically relevant molecules in interstellar clouds and in comets, (2) mid-infrared spectra of interstellar grains and the dust from comets, (3) a diverse set of data from comets including the Rosetta mission showing consistency with biology and (4) the frequency of Earth-like or habitable planets in the Galaxy. We argue that the conjunction of all the available data suggests the operation of cometary biology and interstellar panspermia rather than the much weaker hypothesis of comets being only the source of the chemical building blocks of life. We conclude with specific predictions on the properties expected of extra-terrestrial life if it is discovered on Enceladus, Europa or beyond. A radically different biochemistry elsewhere can be considered as a falsification of the theory of interstellar panspermia.

scholarly journals Spatially resolving the chemical composition of the planet building blocks

2020 ◽  
Vol 497 (3) ◽  
pp. 2540-2552
Author(s):  
A Matter ◽  
F C Pignatale ◽  
B Lopez
Keyword(s):  
Building Blocks ◽  
Mid Infrared ◽  
Future Studies ◽  
Disc Model ◽  
T Tauri ◽  
Very Large Telescope ◽  
Fine Chemistry ◽  
Dust Composition ◽  
Band Spectra ◽  
Complex Chemistry

ABSTRACT The inner regions of protoplanetary discs (from ∼0.1 to 10 au) are the expected birthplace of planets, especially telluric. In those high-temperature regions, solids can experience cyclical annealing, vapourisation, and recondensation. Hot and warm dusty grains emit mostly in the infrared domain, notably in N-band (8–13 μm). Studying their fine chemistry through mid-infrared spectro-interferometry with the new Very Large Telescope Interferometer (VLTI) instrument Multi AperTure mid-Infrared SpectroScopic Experiment (MATISSE), which can spatially resolve these regions, requires detailed dust chemistry models. Using radiative transfer, we derived infrared spectra of a fiducial static protoplanetary disc model with different inner-disc (<1 au) dust compositions. The latter were derived from condensation sequences computed at local thermodynamic equilibrium (LTE) for three initial C/O ratios: subsolar (C/O = 0.4), solar (C/O = 0.54), and supersolar (C/O = 1). The three scenarios return very different N-band spectra, especially when considering the presence of sub-micron-sized dust grains. MATISSE should be able to detect these differences and trace the associated sub-au-scale radial changes. We propose a first interpretation of N-band ‘inner-disc’ spectra obtained with the former VLTI instrument MID-infrared Interferometric instrument (MIDI) on three Herbig stars (HD 142527, HD 144432, HD 163296) and one T Tauri star (AS 209). Notably, we could associate a supersolar (‘carbon-rich’) composition for HD 142527 and a subsolar (‘oxygen-rich’) one for HD 1444432. We show that the inner-disc mineralogy can be very specific and not related to the dust composition derived from spatially unresolved mid-infrared spectroscopy. We highlight the need for including more complex chemistry when interpreting solid-state spectroscopic observations of the inner regions of discs, and for considering dynamical aspects for future studies.

scholarly journals Germanium-based integrated photonics from near- to mid-infrared applications

Nanophotonics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 1781-1793 ◽  
Author(s):  
Delphine Marris-Morini ◽  
Vladyslav Vakarin ◽  
Joan Manel Ramirez ◽  
Qiankun Liu ◽  
Andrea Ballabio ◽  
...  
Keyword(s):  
Silicon Photonics ◽  
High Performance ◽  
Optical Sensing ◽  
Building Blocks ◽  
Transparency Window ◽  
Integrated Photonics ◽  
Mid Infrared ◽  
Monolithically Integrated ◽  
Laser Sources

AbstractGermanium (Ge) has played a key role in silicon photonics as an enabling material for datacom applications. Indeed, the unique properties of Ge have been leveraged to develop high performance integrated photodectors, which are now mature devices. Ge is also very useful for the achievement of compact modulators and monolithically integrated laser sources on silicon. Interestingly, research efforts in these domains also put forward the current revolution of mid-IR photonics. Ge and Ge-based alloys also present strong advantages for mid-infrared photonic platform such as the extension of the transparency window for these materials, which can operate at wavelengths beyond 8 μm. Different platforms have been proposed to take benefit from the broad transparency of Ge up to 15 μm, and the main passive building blocks are now being developed. In this review, we will present the most relevant Ge-based platforms reported so far that have led to the demonstration of several passive and active building blocks for mid-IR photonics. Seminal works on mid-IR optical sensing using integrated platforms will also be reviewed.

scholarly journals Wideband Ge-Rich SiGe Polarization-Insensitive Waveguides for Mid-Infrared Free-Space Communications

2018 ◽  
Vol 8 (7) ◽  
pp. 1154 ◽  
Author(s):  
Vladyslav Vakarin ◽  
Joan Ramírez ◽  
Jacopo Frigerio ◽  
Qiankun Liu ◽  
Andrea Ballabio ◽  
...  
Keyword(s):  
Free Space ◽  
Communication Systems ◽  
Quantum Cascade Lasers ◽  
Building Blocks ◽  
Ultra Wideband ◽  
Power Splitting ◽  
Space Communications ◽  
Mid Infrared ◽  
Atmospheric Transparency ◽  
Polarization Insensitive

The recent development of quantum cascade lasers, with room-temperature emission in the mid-infrared range, opened new opportunities for the implementation of ultra-wideband communication systems. Specifically, the mid-infrared atmospheric transparency windows, comprising wavelengths between 3–5 µm and 8–14 µm, have great potential for free-space communications, as they provide a wide unregulated spectrum with low Mie and Rayleigh scattering and reduced background noise. Despite the great efforts devoted to the development of mid-infrared sources and detectors, little attention is dedicated to the management of polarization for signal processing. In this work, we used Ge-rich SiGe alloys to build a wideband and polarization-insensitive mid-infrared photonic platform. We showed that the gradual index change in the SiGe alloys enabled the design of waveguides with remarkably low birefringence, below 2 × 10−4, over ultra-wide wavelength ranges within both atmospheric transparency windows, near wavelengths of 3.5 µm and 9 µm. We also report on the design of a polarization-independent multimode interference device achieving efficient power splitting in an unprecedented 4.5-µm bandwidth at around 10-µm wavelength. The ultra-wideband polarization-insensitive building blocks presented here pave the way for the development of high-performance on-chip photonic circuits for next-generation mid-infrared free-space communication systems.

scholarly journals Mid-infrared integrated photonics on silicon: a perspective

Nanophotonics ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 393-420 ◽  
Author(s):  
Hongtao Lin ◽  
Zhengqian Luo ◽  
Tian Gu ◽  
Lionel C. Kimerling ◽  
Kazumi Wada ◽  
...  
Keyword(s):  
System Integration ◽  
Near Infrared ◽  
Building Blocks ◽  
Integrated Photonics ◽  
Light Sources ◽  
Mid Infrared ◽  
Growth Opportunity ◽  
Constituent Component ◽  
Comprehensive Survey ◽  
On Chip

AbstractThe emergence of silicon photonics over the past two decades has established silicon as a preferred substrate platform for photonic integration. While most silicon-based photonic components have so far been realized in the near-infrared (near-IR) telecommunication bands, the mid-infrared (mid-IR, 2–20-μm wavelength) band presents a significant growth opportunity for integrated photonics. In this review, we offer our perspective on the burgeoning field of mid-IR integrated photonics on silicon. A comprehensive survey on the state-of-the-art of key photonic devices such as waveguides, light sources, modulators, and detectors is presented. Furthermore, on-chip spectroscopic chemical sensing is quantitatively analyzed as an example of mid-IR photonic system integration based on these basic building blocks, and the constituent component choices are discussed and contrasted in the context of system performance and integration technologies.

Photochemical Evolution of Interstellar/Precometary Organic Material

1997 ◽  
Vol 161 ◽  
pp. 23-47 ◽  
Author(s):  
Louis J. Allamandola ◽  
Max P. Bernstein ◽  
Scott A. Sandford
Keyword(s):  
Origin Of Life ◽  
Building Blocks ◽  
Complex Species ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Polycyclic Aromatic ◽  
Ultraviolet Photolysis ◽  
The Origin Of Life ◽  
Simple Molecules ◽  
Complex Organic

AbstractInfrared observations, combined with realistic laboratory simulations, have revolutionized our understanding of interstellar ice and dust, the building blocks of comets. Since comets are thought to be a major source of the volatiles on the primative earth, their organic inventory is of central importance to questions concerning the origin of life. Ices in molecular clouds contain the very simple molecules H2O, CH3OH, CO, CO2, CH4, H2, and probably some NH3and H2CO, as well as more complex species including nitriles, ketones, and esters. The evidence for these, as well as carbonrich materials such as polycyclic aromatic hydrocarbons (PAHs), microdiamonds, and amorphous carbon is briefly reviewed. This is followed by a detailed summary of interstellar/precometary ice photochemical evolution based on laboratory studies of realistic polar ice analogs. Ultraviolet photolysis of these ices produces H2, H2CO, CO2, CO, CH4, HCO, and the moderately complex organic molecules: CH3CH2OH (ethanol), HC(= O)NH2(formamide), CH3C(= O)NH2(acetamide), R-CN (nitriles), and hexamethylenetetramine (HMT, C6H12N4), as well as more complex species including polyoxymethylene and related species (POMs), amides, and ketones. The ready formation of these organic species from simple starting mixtures, the ice chemistry that ensues when these ices are mildly warmed, plus the observation that the more complex refractory photoproducts show lipid-like behavior and readily self organize into droplets upon exposure to liquid water suggest that comets may have played an important role in the origin of life.

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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