We compare visible-pump mid-infrared-probe femtosecond measurement of electron injection on dye-sensitized mesoporous TiO2 films immersed in neat solvent or I–/I3– electrolyte. Results are presented for the Ru-polypyridyl dyes N3 and N719 organic dye D149. Using type electrolyte required to make efficient stable sensitized solar cells (DSSCs), we find multiple exponential dynamics, ranging from <300 fs 0.5 ns ruthenium metal-centered dyes. The D149 shows double 30 ps kinetics. show that this...

Photosystem I (PSI) from Chroococcidiopsis thermalis PCC 7203 grown under far-red light (FRL; >725 nm) contains both chlorophyll a and small proportion of f. Here, we investigated excitation energy transfer charge separation using this FRL-grown form PSI (FRL-PSI). We compared femtosecond transient visible absorption changes normal, white-light (WL)-grown (WL-PSI) with those FRL-PSI at 670 nm, 700 (in the case FRL-PSI) 740 nm. The possibility that f participates in or is discussed on basis...

The fast-switching M159T mutant of the reversibly photoswitchable fluorescent protein Dronpa has an enhanced yield for on-to-off reaction. forward and reverse photoreactions proceed via cis-trans trans-cis photoisomerization, yet protonation deprotonation hydroxyphenyl oxygen chromophore is responsible majority resulting spectroscopic contrast. Ultrafast visible-pump, infrared-probe spectroscopy was used to detect picosecond, nanosecond, as well metastable millisecond intermediates....

The recent discovery of extremely red-shifted chlorophyll f pigments in both photosystem I (PSI) and II has led to the conclusion that plays a role not only energy transfer, but also charge separation processes [Nürnberg et al., Science, 2018, 360, 1210-1213]. We have employed ultrafast transient infrared absorption spectroscopy study contribution far-red light absorbing transfer light-grown PSI (FRL-PSI) from cyanobacterium Chroococcidiopsis thermalis PCC 7203. compare kinetics spectra...

We present femtosecond to nanosecond transient absorption (TA) data on electron injection in dye-sensitized solar cells (DSSCs) fabricated with low volatility, commercially relevant electrolytes, and without added lithium. Results are shown over an extended time range (300 fs–6.3 ns) wavelength (800–1400 nm) for both N719 C106 dyes. Kinetics were measured TiO2 noninjecting ZrO2. Using the latter, we have determined spectra coefficient of N719* across range. find isosbestic point TA near 900...

Abstract In oxygenic photosynthesis, two photosystems work in series. Each of them contains a reaction centre that is surrounded by light-harvesting antennae, which absorb the light and transfer excitation energy to where electron reactions are driven. Here we report critical test for contrasting models harvesting photosystem II cores, known as trap-limited transfer-to-the model. Oriented single crystals core complexes Synechococcus elongatus excited polarized visible transient absorption...

Significance Far-red photosystem II (FR-PSII) contains a small number of FR-chlorophylls (- f or - d ) with the rest (∼85%) being chlorophyll- molecules. Here ultrafast studies on FR-PSII support model in which primary electron donor is FR-chlorophyll (P 720 , likely Chl D1 position), while second at P position, forming +• . Excitation energy transfer from to ultrafast. The excited state remains highly localized, i.e., * does not share excitation pigments. This markedly different both...

A setup of ultrafast transient infrared IR spectrometer is described in this paper that employed Schwarzschild objectives to focus the probe beam a diffraction limited spot. Thus measurements were performed with very high spatial resolution mid-IR spectral region. Furthermore, modulating polarization light enabled detecting dichroism sample. These capabilities applied study absorption Photosystem II core complex and image an organized film methylene blue chloride dye. Moreover, noise sources...

We describe a mobile spectroscopic system for trace gas analysis based on the open path differential absorption spectrometer and photoacoustic spectrometer. The first method allows long distance measurements (up to few kilometers) while second one provides local in situ detection of pollutants. is nanosecond (f=10Hz, τ≈5ns) lamp pumped Nd:YAG laser tunable two cascade optical parametric generator operating 5–12μm spectral region. This source was mounted into lidar setup coaxial...

Abstract We present a coherent anti-Stokes Raman scattering (CARS) microscope based on robust and simple laser source. A picosecond operating in cavity dumping regime at the 1 MHz repetition rate was used to pump traveling wave optical parametric generator, which serves as two-color excitation light source for CARS microscope. demonstrate ability of presented measure spectra images by using several detection schemes. Keywords: scatteringlaser sourcetraveling generator Acknowledgements This...

The fluorescent protein Dronpa undergoes reversible photoswitching reactions between the bright "on" and dark "off" states via photoisomerization proton transfer reactions. We report room temperature crystal structure of fast switching Met159Thr mutant at 2.0-Å resolution in on state. Structural differences with wild type include shifted backbone positions strand β8 containing Thr159 as well an altered A-C dimer interface involving strands β7, β8, β10, β11. mutation increases cavity volume...

The paper analyses some equipment and methodological aspects of atmospheric pollution monitoring by infrared lidars.Features optical parametric oscillators (including our created two-stage system) operating in the spectral ranges molecular fundamental vibrations are discussed.The environment protection industry demands for this remote technology considered.Despite progress low detection limits achieved, reliable fast identification pollutants is far from perfection.Inner outer factors...

We describe all solid state differential absorption lidar (DIAL) based on the mid-infrared (IR) tunable Optical Parametric Oscillator (OPO). Generation of laser radiation using a two stage tandem OPO was demonstrated. The first nonlinear KTP crystal and produced up to 45 mJ 1.57 μm radiation, while pumped by commercial Q-switched Nd:YAG laser. quality signal beam improved use unstable resonator. AgGaSe₂ used in second OPO. Idler energies 1 were generated at this within tuning...

High sensitivity and selectivity of gas/vapour detection are achieved employing registration laser photoacoustic spectra. The lasers usually operated in the continuous-wave (CW) single-frequency mode. tuning range single CW system is not sufficient to cover spectral bands variety gases/vapours interest. optical parametric oscillator (OPO) systems more preferential for multi component analyzers allowing simultaneous measurement different gases or pollutants. Pumped by same 7 ns duration pulse...

We describe a new project (acronym LISATNAS) approved by the Lithuanian Research Council in 2003 devoted to development of differential absorption lidar (DIAL) and stationary spectrometric systems based on mid-infrared tunable Optical Parametric Oscillator (OPO), pumped compact Q-switched lasers. The purpose is construct mobile infrared lidar, assembled truck for selective pollutant analysis - possessing spatial resolution few meters distance range extending from hundred kilometers. A...

This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where interplay between crystal orientations, cut angles and air dispersion substantially influenced OPO performance, especially angular spectrum output beam. Theory suggests that if BBO crystals are used in this type design, they should be different cuts. aims to provide experimental manifestation fact. Furthermore, it has been shown produces similar...

We describe a new development of differential absorption DIAL spectrometric system based on the mid-infrared tunable Optical Parametric Oscillator (OPO), pumped by compact Q-switched lasers. Mobile LIDAR was assembled in truck and is devoted for selective pollutant analysis distance range extending from hundred meters to few kilometers. A reliable cascade mid-IR generation scheme developed. Pulse energies up milijoule (&#955;=8-12 &#956;m) have been already obtained using nonlinear...

We present the second phase of our work in project LISATNAS devoted to design differential absorption lidar (DIAL) based on mid-infrared (IR) tunable Optical Parametric Oscillator (OPO). Generation laser radiation using a two stage tandem OPO was demonstrated. The first nonlinear KTP crystal and produced up 45 mJ 1.57 &#956;m radiation, while pumped by commercial Q-switched Nd:YAG laser. quality signal beam improved use unstable resonator. AgGaSe2 used OPO. Idler energies 1.2 were generated...

The operation of a middle infrared laser source based on the tandem optical parametric oscillator (OPO) was demonstrated.The first stage nonlinear KTP crystal and produced up to 45 mJ 1.57 µm radiation, while pumped by commercial Q-switched Nd:YAG laser.The quality signal beam improved using unstable resonator.The AgGaSe2 used in second OPO.Idler energies 1.2 were generated this within tuning range from 5 12 µm.

The performance of phototoacoustic gas registration using a broad-band optical parametric oscillator (OPO)was tested. OPO was capable generating tunable pulses about 7 ns duration and 5 cm −1 spectral bandwidth in the 0.72–1.9 µm range (idler), thus covering overtones stretching vibrations combination hydrogen atom analyte molecules. A nonresonant one microphone acoustic scheme employed. measured spectra water vapour methane conform with absorption calculated aid HITRAN database. For 1.361...