The temperature dependence of the absorption and fluorescence spectra colloidal CdSe nanocrystals was compared for three different shapes (dots, rods, tetrapods) in range 4–300K. While shift maximum indicates little on shape, authors find that broadening emission spectrum behaves very differently dots indicating major differences mechanisms shapes. Tetrapods behave more similarly to dots, which suggests lowest exciton state is centered at core.

Photonic sensors that operate in the mid-infrared spectral range are an emerging field for photonic microsystems. In this paper, we present a gas sensor concept based on silicon waveguides using infrared evanescent absorption. The were specifically designed CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> sensing at wavelength of λ = 4.26μm as possible application proposed platform. waveguide cross section well substructure...

LIDAR sensors and systems are gaining popularity, but their effectiveness can be compromised by light reflections in foggy conditions. To address the need for small, laboratory-scale testing systems, a fog chamber was developed tested to have laboratory environment. Two different methods produce were evaluated: hot steam ultrasonic nebulizers. The cold from nebulizers more prone stratification, while produced rather disturbing condensation measurement. All this solved implementing improving...

We show a femtosecond fluorescence upconversion setup with broadband detection to measure time-resolved emission spectra in the 300-550 nm range, upon excitation between 250 and 300 nm, time resolution of 100 fs. present 2,5-diphenyloxazole solution, which demonstrate capabilities setup.

We report on the (sub)picosecond relaxation processes in PbSe quantum dots of different sizes, measured by a near-infrared photoluminescence upconversion technique. The early-time spectra are characterized emission from several low-lying excited states. direct measurement Huang-Rhys factors lowest states excludes strong electron-phonon coupling intraband relaxation. kinetics point to fast sequential cascade process between states, governed energy gaps and quasicontinuous valence-band structure.

Photoexcitations coupled to intrachain, backbone modes of a flexible π-conjugated polyarylene polymer and their effect on the relaxational dynamics migrative excitation transfer have been examined by using femtosecond picosecond time resolved fluorescence techniques. In poly[4,4'-diphenylene-1,2-di(3,4-dimethoxyphenyl)vinylene], DMOP-PDPV, vertical into biphenylic segmental unit is subject quasi-instantaneous torsional, energetic relaxation that gives rise large bathochromic shift gated...

We report on an ultrafast experimental and simulations study of the early relaxation events photoexcited tryptophan in water. Experimentally, we used fluorescence up-conversion both polychromatic single wavelength detection modes 300−480 nm range with polarization dependence. time evolution Stokes shift, bandwidth, anisotropy from tens femtoseconds to picoseconds. These observables contain signatures simultaneous occurrence intramolecular solvent−molecule interactions, which disentangle help...

The detection of infrared radiation is great interest for a wide range applications, such as absorption sensing in the spectral range. In this work, we present CMOS compatible pyroelectric detector which was devised mid-infrared detector, comprising aluminium nitride (AlN) material and fabricated using semiconductor mass fabrication processes. To ensure thermal decoupling detectors are realized on Si3N4/SiO2 membrane. have been tested at wavelength close to CO2 region mid-infrared. Devices...

This paper presents a systematic approach to transduction optimization of resonant piezo-based MEMS devices. The method is based on inverse design using direct piezoelectric effect and exploits mechanical action desired mode calculate the polarization map ceramics. Optimal achieved by matching excited electric field distribution inversely retrieved electrode segmentation topology technique. proposed was applied improve existing state-of-the-art mirrors. optimized devices feature 70% increase...

Highly reactive integrated material systems have recently gained attention, as they promise a feasible tool for heterogeneous integration of micro electromechanical systems. As energy sources can be used to join materials without applying too much thermal stress the whole device. An alternative approach is proposed, comprising single layer nanocomposite made intermixed metal nanoparticles, instead multilayer In this study development from choice through processing steps, handling and...

The principle of coherence observation by interference noise [COIN, Kinrot et al., Phys. Rev. Lett. 75, 3822 (1995)] has been applied as a new approach to measuring wavepacket motion. In the COIN experiment pairs phase-randomized femtosecond pulses with relative delay time τ prepare fluctuations in excited state population, so correlated fluorescence intensity—the variance varF(τ)—directly mimics dynamics propagating wavepacket. scheme is demonstrated vibrational motion B-state gaseous...

The fluorescence intensity of the two flavin prosthetic groups, FMN and FAD, in neuronal nitric oxide synthase (nNOS) was found to decay highly nonexponentially, being best described by four lifetimes. This excited state heterogeneity is result multiple quenching sites which are due several microenvironments created mainly stacking with aromatic amino acids. Investigating nNOS absence one or more Ca2+/calmodulin, tetrahydrobiopterin, heme revealed an influence these cofactors on groups....

With a trend towards the use of spectroscopic systems in various fields science and industry, there is an increasing demand for compact spectrometers. For UV/VIS to shortwave near-infrared spectral range, hand-held polychromator type devices are widely used have replaced larger conventional instruments many applications. Still, longer wavelengths this spectrometers lacking suitable affordable detector arrays. In perennial development Carinthian Tech Research AG together with Fraunhofer...

We present a comprehensive experimental and computational study on fs-relaxational dynamics of optical excitations in the conjugated polymer poly(p-phenylenevinylene) (PPV) under selective excitation tuning conditions into long-wavelength, low-vibrational S1ν=0-density-of-states (DOS). The dependence single-wavelength luminescence kinetics time-windowed spectral transients distinct, initial boundaries at 1.4 K room temperature was measured applying up-conversion technique. typical...

The method of coherence observation by interference noise (COIN) [Kinrot et al., Phys. Rev. Lett. 75, 3822 (1995)] has been shown to be a useful tool for measurements wave packet motion at the quantum-classical border. We present first systematic interferometric study fractional vibrational revivals in B state thermal iodine (I2) vapor. Experimental COIN interferograms ranging from 200 fs 40 ps are presented various excitation wavelengths. complex temporal structure observed fluorescence...

Probing electronic femtosecond (fs) coherence among segmental sites that are congested by static and dynamic site disorder subject to structural relaxation is a big, experimental challenge in the study of photophysics poly(p-phenylenevinylene). In this work, fs-wave-packet fluorescence interferometry experiments presented measure macroscopic coherent kernels their phase-relaxation low-temperature, bottom-state regime density-of-states below migrational threshold energy where downhill...

We present an improved FTIR spectrometer using a novel MOEMS actuator and discuss in detail the properties of component resulting FT-IR sensor device. Spectral resolution spectral range allow making use inherent multi-analyte detection capabilities giving spectroscopy platform advantage over singlewavelength IR sensors. With its further miniaturization potential due to core, this compact, energy efficient robust can thus act as transducer for portable ultra-lightweight spectroscopic sensors,...

We present an evanescent-field absorption gas sensor based on a silicon slab waveguide. describe the finite element simulations that were used to design waveguide structures and furthermore spectroscopic measurements of CO2, which show we can resolve rotational-vibrational spectrum under test. Although waveguides are not capable sensing ppm concentrations, due short interaction length with gas, results demonstrate feasibility approach provide valuable input for next generation structures.

The field of mid-infrared (MIR) plasmonics has shown great potential applications in spectroscopic sensing, infrared light sources and detectors. MIR plasmonic materials that are compatible with common fabrication processes may enable cost-effective reliable device platforms. In this work, we examined aluminium metal (Al), gold-tin (AuSn) titanium-tungsten (TiW) alloys regarding their usability for surface plasmon polariton (SPP) excitation the regime using a grating configuration. angle...