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We review recent studies of cavity switching induced by the optical injection of free carriers in micropillar cavities containing quantum dots. Using the quantum dots as a broadband internal light source and a streak camera as detector, we track the resonance frequencies for a large set of modes with picosecond time resolution. We report a record-fast switch-on time constant (1.5 ps) and observe major transient modifications of the modal structure of the micropillar on the 10 ps time scale: mode crossings are induced by a focused symmetric injection of free carriers, while a lifting of several mode degeneracies is observed when off-axis injection breaks the rotational symmetry of the micropillar. We show theoretically and experimentally that cavity switching can be used to tailor the dynamic properties of the coupled QD–cavity system. We report the generation of ultrashort spontaneous emission pulses (as short as 6 ps duration) by a collection of frequency-selected QDs in a switched pillar microcavity. These pulses display a very small coherence length, attractive for ultrafast speckle-free imaging. Moreover, the control of QD-mode coupling on the 10 ps time scale establishes cavity switching as an appealing resource for quantum photonics.

We present a table-top extreme ultraviolet (XUV) beamline for measuring time- and frequency-resolved XUV-excited optical luminescence (XEOL) with additional femtosecond-resolution XUV transient absorption spectroscopy functionality. XUV pulses are generated via high-harmonic generation using a near-infrared pulse in a noble gas medium and focused to excite luminescence from a solid sample. The luminescence is collimated and guided into a streak camera where its spectral components are temporally resolved with picosecond temporal resolution. We time-resolve XUV-excited luminescence and compare the results to luminescence decays excited at longer wavelengths for three different materials: (i) sodium salicylate, an often used XUV scintillator; (ii) fluorescent labeling molecule 4-carbazole benzoic (CB) acid; and (iii) a zirconium metal oxo-cluster labeled with CB, which is a photoresist candidate for extreme-ultraviolet lithography. Our results establish time-resolved XEOL as a new technique to measure transient XUV-driven phenomena in solid-state samples and identify decay mechanisms of molecules following XUV and soft-x-ray excitation.

We report the study of the fast rise time and decay time in the ps time scale of the excitonic luminescence of a multiple quantum well (MQW) heterostructure of InGaN/GaN, including the excitation density effect. These structures were proposed as ultrafast scintillators for soft X-ray detectors and particle beam diagnostics. Measurements were carried out with a Hadland Imacon 500 streak camera following excitation of the sample by laser pulses of few tens of µJ at 266 nm and 400 nm, with pulse duration less than 200 fs. The rise time of the detected MWQ luminescence was less than 10 ps, with a possible contribution from the detection system and signal collection geometry. The calibration and the signal processing techniques employed to fully exploit the time resolution of the detection system are also described.

The results of the development of a technique for measuring the power contrast of a laser pulse by registering the pulse-front profile with a large dynamic range are presented. The technique was developed on the basis of a high-speed streak camera and fiber-optic transmission lines; it provides the following registration parameters: the dynamic range of measuring the laser-pulse power contrast at the wavelength λ = 0.53 µm is 107, while the temporal resolution of the registration channel is no worse than 60 ps. A method of increasing the power contrast to 1011 using an optical scheme based on elements with nonlinear transmission is shown.

We are planning detailed spectroscopic studies of the X-ray bursts produced by hybrid X-pinches using a ~20 ps time resolution X-ray streak camera and ~700 ps resolution filtered silicon diodes. The purpose is to investigate whether the X-ray spectroscopic features associated with radiative collapse can be seen in the X-ray bursts produced by the Hybrid X-pinches. A nickel wire has been used as the load and time integrated L and K-shell spectra were recorded on imaging plates. In addition, silicon diodes were focused on specific emission lines from the X-ray spectrometer crystals to track their intensity evolution. Time-resolved temperature and density measurements can be estimated throughout the implosion and expansion phases from these diagnostics. Time-resolved source size measurements are also being carried out using the ~20 ps time resolved streak camera to determine the change of the spot size on a picosecond timescale. Sufficiently high magnification studies are being carried to determine the source size in the 1-10 µm range.

Fundamental information on the behavior of excited chlorophyll molecules packed within the confinements of nanosized photosystems I and II, following absorption of light, is presented. Using a 100 femtosecond laser with nanojoule (nJ) pulse energy and a one picosecond streak camera, we observed the light emitted from the nanostructured photosystems without oscillations or hops. The fluorescent exponential decay profiles and high efficiency within the nanostructure suggest that light coherently drains out as a unit. This implies that "quantumness" is linked to quantum confinement on the nano scale.

Spontaneous emission from individual atoms in vapor lasts nanoseconds, if not microseconds, and beatings in this emission involve only directly excited energy sublevels. In contrast, the superfluorescent emissions burst on a much-reduced timescale and their beatings involve both directly and indirectly excited energy sublevels. In this work, picosecond and femtosecond superfluorescent beatings are observed from a dense cesium atomic vapor. Cesium atoms are excited by 60-femtosecond long, 800 nm laser pulses via two-photon processes into their coherent superpositions of the ground 6S and excited 8S states. As a part of the transient four wave mixing process, the yoked superfluorescent blue light at lower transitions of 6S - 7P are recorded and studied. Delayed buildup time of this blue light is measured as a function of the input laser beam power using a high-resolution 2 ps streak camera. The power dependent buildup delay time is consistently doubled as the vapor temperature is lowered to cut the number of atoms by half. At low power and density, a beating with a period of 100 picoseconds representing the ground state splitting is observed. The autocorrelation measurements of the generated blue light exhibit a beating with a quasi-period of 230 fs corresponding to the splitting of the 7P level primarily at lower input laser power. Understanding and, eventually, controlling the intriguing nature of superfluorescent beatings may permit a rapid quantum operation free from the rather slow spontaneous emission processes from atoms and molecules., Comment: 7 pages, 5 figures

We report on ultrafast all-optical switching experiments performed on pillar microcavities containing a collection of quantum dots (QDs). Using QDs as a broadband internal light source and a detection setup based on a streak camera, we track in parallel the frequencies of a large set (>10) of resonant modes of an isolated micropillar during the entire duration of switching events and with a 2 ps temporal resolution. Being much faster and more convenient than standard approaches based on pump–probe spectroscopy, this method is very well suited forin-depth studies of cavity switching, noticeably in view of applications in the field of quantum photonics. We report as a first demonstrative example an investigation of the switch-on time constant tau_on dependence as a function of the pump power and the observation of a remarkably low value of tau-on(≈1.5 ps) for optimized pumping conditions. As a second illustration, we report the observation of a transient lifting of the degeneracy of a polarization-degenerate cavity mode, induced by a non-centrosymmetric injection of free carriers.

A new type K016M streak camera developed at VNIIOFI was used to measure the temporal shape of individual pulses emitted by commercial nanosecond pulsed solid-state laser. It has been shown that the streak camera having picosecond temporal resolution can reveal the fine structure of temporal shape of the laser pulse that is not detected by oscilloscopic measurement.

The paper belongs to the field of ultrafast optics. Acousto-optic pulse shaping has been studied experimentally for binary intensity modulation in a chirped pulse amplification laser system. Direct time-domain measurement of modulation rise/fall time with a picosecond streak camera was performed for a Ti:sapphire regenerative amplifier. It was discovered that the sign of the second order dispersion produced by the acousto-optic dispersion delay line affects the modulation rise/fall time. Two algorithms for synthesis of ultrasonic waveforms for feeding the delay line, dispersive Fourier synthesis and the Gerchberg-Saxton algorithm, were compared. Minimum modulation rise/fall time of 3.6 ps for 3 mJ pulses with the linear chirp of 6.2 ps/nm at the wavelength of 795 nm was obtained.

The streak camera is a picosecond resolution photodetector with parallel input capability; however, the degree of multiplexing is limited by crosstalk and temporal uncertainty in the sweeping field. We introduced a fixed time delay between adjacent fibers to reduce crosstalk in the synchroscan mode. The fixed delay and a tunable electronic delay between the input pulse and the synchroscan unit allows robust separation modes between the streaks, while spatial and temporal nonlinearities can be calibrated in. The efficacy of the design is demonstrated through a 100-fold multiplexed confocal fluorescence lifetime imaging microscope in live cells.

The application of a PS-1/S1 picosecond streak camera (SC), which was developed at the General Physics Institute (Russian Academy of Sciences) for investigating fast processes in semiconductor physics, laser physics, and accelerator engineering, is described. It is shown that using the PS-1/S1 SC it is possible to record one-dimensional images (restricted by a narrow slit) of fast processes with a time resolution of no worse than 1 ps in a wide spectral range: from UV (115 nm) to near-IR (1.5 μm) radiation with a dynamic recording range of ≥10. The presented experimental results show the wide potential capabilities of applying the developed SC in various fields of experimental physics.

In direct experiments, rate constants of photochemical (kP) and non-photochemical (kP(+)) fluorescence quenching were determined in membrane fragments of photosystem II (PSII), in oxygen-evolving PSII core particles, as well as in core particles deprived of the oxygen-evolving complex. For this purpose, a new approach to the pulse fluorometry method was implemented. In the "dark" reaction center (RC) state, antenna fluorescence decay kinetics were measured under low-intensity excitation (532 nm, pulse repetition rate 1 Hz), and the emission was registered by a streak camera. To create a "closed" [P680(+)QA(-)] RC state, a high-intensity pre-excitation pulse (pump pulse, 532 nm) of the sample was used. The time advance of the pump pulse against the measuring pulse was 8 ns. In this experimental configuration, under the pump pulse, the [P680(+)QA(-)] state was formed in RC, whereupon antenna fluorescence kinetics was measured using a weak testing picosecond pulsed excitation light applied to the sample 8 ns after the pump pulse. The data were fitted by a two-exponential approximation. Efficiency of antenna fluorescence quenching by the photoactive RC pigment in its oxidized (P680(+)) state was found to be ~1.5 times higher than that of the neutral (P680) RC state. To verify the data obtained with a streak camera, control measurements of PSII complex fluorescence decay kinetics by the single-photon counting technique were carried out. The results support the conclusions drawn from the measurements registered with the streak camera. In this case, the fitting of fluorescence kinetics was performed in three-exponential approximation, using the value of τ1 obtained by analyzing data registered by the streak camera. An additional third component obtained by modeling the data of single photon counting describes the P680(+)Pheo(-) charge recombination. Thus, for the first time the ratio of kP(+)/kP = 1.5 was determined in a direct experiment. The mechanisms of higher efficiency for non-photochemical antenna fluorescence quenching by RC cation radical in comparison to that of photochemical quenching are discussed.

This paper describes a new image-tube dissector based on a PIF-01 chronographic image-tube device developed and manufactured at the Prokhorov General Physics Institute of the Russian Academy of Sciences (PGPI RAS). The results of the static measurements of the instrumental function of the dissector showing that its temporal resolution can be higher than 4 ps are given. These data are confirmed by direct measurements on the bench of the PGPI RAS with the use of a femtosecond titanium-sapphire laser.

The single shot compressed ultrafast photography (CUP) camera is the fastest camera available. This technique is based on random codes to encode and reconstruct the ultrafast dynamical scene by a compressed sensing algorithm. In this paper, a new 2D ultrafast camera with high reliability was introduced and a novel reconstruction algorithm named GAP-TV was proposed. Firstly, this camera was simulated with the TwIST and GAP-TV methods for a simple scene; the result showed that the GAP-TV method had better PSNR and SSIM performance than TwIST. Secondly, the optical propagation process data was performed to this proposed 2D camera, and the result showed that this novel method can reconstruct it well. In addition, the efficiency of the GAP-TV method is excellent than TwIST. Finally, an experiment was conducted to capture the transient event when a femtosecond laser pulse passed through a beam splitter. The result showed that the GAP-TV method can reconstruct the compressed 2D image well, and the CUP system can achieve 1011 frames per second. So, a novel 2D ultrafast camera with high temporal resolution (4 picosecond) was designed and verified. It has wide applications in inertial confined fusion, fluorescence lifetime imaging, and nuclear physics.

In this Letter, we report the direct streak camera measurements of the duration of a lasing pulse from molecular nitrogen ions under various focusing conditions of 10 mJ, 950 nm femtosecond pump pulse in atmospheric pressure air. The parameters of the active medium are analyzed, and a mechanism for formation of picosecond lasing pulse duration at femtosecond seed pulse duration is proposed.

In this paper, we report on the development and manufacture of a dual-slit electron-optical dissector based on the PIF-01 streak image tube with a picosecond time resolution operating in the crossed-sweep mode. The dissector is designed to work on synchrotron radiation sources and electron-positron colliders, when it is necessary to record simultaneously the temporal profiles of electron and positron bunches filling from two to several hundred neighboring separatrices of an accelerator ring. In order to obtain the crossed-sweep mode, high-frequency (HF) sinusoidal voltages with multiple frequencies are fed to two pairs of deflecting plates of the tube, located perpendicular to each other. This separation of pulses will allow separate acquisition of the bunch profiles from neighboring separatrices of an accelerator, which are superimposed on each other in the absence of the crossed sweep. During the tests of the device which have been conducted on a laser system, two trains of light pulses, ”shifted” in time with respect to each other, were recorded with a time resolution of 6 ± 0.5 ps. Improvement of a single slit dissector was also done using the MASIM software. As a result, the temporal resolution of the modernized dissector measured on a femtosecond Ti:sapphire laser was about 1.5 ps. The dissector was tested on the MLS (Berlin, Germany) accelerator. Using both the HAMAMATSU C10910 streak camera and the dissector, comparative measurements of the longitudinal bunch length were performed.

The Advanced Wakefield Experiment (AWAKE) develops the first plasma wakefield accelerator with a high-energy proton bunch as driver. The 400GeV bunch from CERN Super Proton Synchrotron (SPS) propagates through a 10m long rubidium plasma, ionized by a 4TW laser pulse co-propagating with the proton bunch. The relativistic ionization front seeds a self-modulation process. The seeded self-modulation transforms the bunch into a train of micro-bunches resonantly driving wakefields. We measure the density modulation of the bunch, in time, with a streak camera with picosecond resolution. The observed effect corresponds to alternating focusing and defocusing fields. We present a procedure recovering the charge of the bunch from the experimental streak camera images containing the charge density. These studies are important to determine the charge per micro-bunch along the modulated proton bunch and to understand the wakefields driven by the modulated bunch., Comment: EAAC2019 Conference Proceedings, 9 pages, 16 figures

Here, we present an optical fiber-based electron gun designed for the ultrafast streaking of low-energy electron bunches. The temporal profile of the few tens of the picosecond long electron bunch composed of 200 electrons is well characterized using a customized streak camera. Detailed analysis reveals that the stretched optical trigger pulse owing to the dispersion effects inside the waveguide dominantly determines the temporal length of the low density electron bunch. This result illustrates the capability to control the observable time-window in the streak diffraction experiment by tailoring geometrical parameters of the fiber source and its coupling condition. With the electrostatic Einzel lens system integrated on the fiber-based cathode, we also demonstrate spatial focusing of the electron beam with the RMS spot size of 98 μm and imaging of the static low-energy electron diffraction pattern of monolayer graphene in the electron kinetic energy range of 1.0–2.0 keV.

A PS-1/S1 picosecond streak camera with a linear sweep is used to measure temporal characteristics of synchrotron radiation pulses on a damping ring (DR) at the Budker Institute of Nuclear Physics (BINP) of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The data obtained allow a conclusion as to the formation processes of electron bunches and their 'quality' in the DR after injection from the linear accelerator. The expediency of employing the streak camera as a part of an optical diagnostic accelerator complex for adjusting the injection from a linear accelerator is shown. Discussed is the issue of designing a new-generation dissector with a time resolution up to a few picoseconds, which would allow implementation of a continuous bunch monitoring in the DR during mutual work with the electron-positron colliders at the BINP.

The pulse duration of a diode-pumped Nd:YAG laser, in which Q-switching with mode-locking (QML regime) is achieved using a spherical mirror and a travelling-wave acousto-optic modulator, is directly measured with a streak camera. It is found that the picosecond pulses can have a non-single-pulse structure, which is explained by excitation of several competing transverse modes in the Q-switching regime with a pulse repetition rate of 1 kHz. In the case of cw mode-locking (without Q-switching), a new (auto-QML) regime is observed, in which the pulse train repetition rate is determined by the frequency of the relaxation oscillations of the laser field while the train contains single picosecond pulses.

The traveling time of scintillation photons from the ionization track to the photodetector varies from photon to photon. For scintillators used in (time-of-flight) positron emission tomography (TOF-)PET systems the resulting optical transit time-spread can have a significant influence on the timing resolution. Using a femtosecond pulsed diode laser in combination with a fast imaging streak camera we measured this time-spread on the picosecond time scale for both polished and etched Ca co-doped and non co-doped LSO:Ce and LYSO:Ce crystals of $3 \times 3 \times 5 ~\hbox{mm}^3$ , $3 \times 3 \times 10 ~\hbox{mm}^3$ , and $3 \times 3 \times 20 ~\hbox{mm}^3$ in size. Measurements were performed with the crystals wrapped on 5 of their sides in 1 to 4 layers of 0.1 mm thick white reflecting Teflon tape (PTFE). Optical photons can migrate through Teflon tape for some time before they re-enter the crystal. This Teflon time-spread was measured as well. The roughness of the crystal surfaces were determined using a surface profiler. In addition to experiments, the optical transit time-spread was obtained by means of ray-tracing software and compared to experimental data. In addition, an analytical model about optical transit time-spreads was derived.

A picosecond-resolving hard-X-ray streak camera has been in operation for several years at Sector 7 of the Advanced Photon Source (APS). Several upgrades have been implemented over the past few years to optimize integration into the beamline, reduce the timing jitter, and improve the signal-to-noise ratio. These include the development of X-ray optics for focusing the X-rays into the sample and the entrance slit of the streak camera, and measures to minimize the amount of laser light needed to generate the deflection-voltage ramp. For the latter, the photoconductive switch generating the deflection ramp was replaced with microwave power electronics. With these, the streak camera operates routinely at 88 MHz repetition rate, thus making it compatible with all of the APS fill patterns including use of all the X-rays in the 324-bunch mode. Sample data are shown to demonstrate the performance.

We report a new method using high-stability, laser-driven supercontinuum generation in a liquid cell to calibrate the absolute photon response of fast optical streak cameras as a function of wavelength when operating at fastest sweep speeds. A stable, pulsed white light source based around the use of self-phase modulation in a salt solution was developed to provide the required brightness on picosecond time scales, enabling streak camera calibration in fully dynamic operation. The measured spectral brightness allowed for absolute photon response calibration over a broad spectral range (425-650 nm). Calibrations performed with two Axis Photonique streak cameras using the Photonis P820PSU streak tube demonstrated responses that qualitatively follow the photocathode response. Peak sensitivities were one photon/count above background. The absolute dynamic sensitivity is less than the static by up to an order of magnitude. We attribute this to the dynamic response of the phosphor being lower.

Analysis of wavefront is vital in the process of the inertial confinement fusion (ICF), but there is lack of accurate method to achieve the wavefront image with a high resolution of up to the picosecond (ps) level. The two-dimensional imaging velocity interferometer system for any reflectors (2D-VISAR) can only realize two-dimensional images with a temporal resolution in a nanosecond scale or one two-dimensional image, leading to the difficulties in recovering the high-speed changing process. Although the line-imaging VISAR with a streak camera has a higher temporal resolution of 5 ps, it hardly offers two-dimensional images. In this study, we design a diagnostic system by coupling the line-imaging VISAR and compressed sensing theory to recover the wavefront profile, by which both the two-dimensional and high-temporal resolution wavefront are obtained. A series of original fringe images are firstly processed, and then acquiring data and reconstructing images are simulated, which results in corresponding reconstructed fringe images. The deviation of the resulting images is evaluated to be below 2.1% for the reconstructed shock wave velocities compared to the original shock wave velocities, much lower than the initial velocity, suggesting that the wavefront profile change is successfully recovered, which indicates the diagnostic system for more accurate measurements of the wavefront profile is feasible. This new system is expected to be applied in the field of implosion to provide more extensive information.

This IUPAC Technical Report describes and compares the currently applied methods for measuring and analyzing time-resolved fluorescence traces using phase-modulation fluorometry as well as pulse fluorometry (direct emission decay measurements, single-photon timing, streak camera measurements, fluorescence upconversion, and optical Kerr gating). The paper starts with a brief description of the basic principles for time and frequency domain fluorescence spectroscopy. The fundamental equations are given, and recommendations for adequate use are emphasized. The up-to-date, commonly employed excitation sources and photodetectors are described in detail. The analysis of time-resolved fluorescence data is discussed. Attention is paid to possible artifacts, and remedies are presented on how to avoid them or to account for them. Finally, fluorescence lifetime standards for the nanosecond and picosecond timescales are collected.

Broadly tunable picosecond pulses in the UV for nonlinear microscopy and lifetime measurements are not yet readily available. Complex synchronously pumped optical parametric oscillators with subsequent frequency doubling are typically used. We show that direct second harmonic generation of a visible picosecond supercontinuum source at 78 MHz renders pulses easily tunable from 250 to 430 nm. We find that an unexpectedly large numerical aperture and the use of thick crystals increase the efficiency of the frequency doubling process dramatically. The observed spectral width and efficiency are nearly two orders of magnitude larger than predicted by conventional theory. With broadband achromatic doubling, a 130 nm wide spectrum is achieved. Pulse durations of 17–35 ps are found in the UV and an average power between 1 and 70 μW. This qualifies the setup for most UV-based microscopic investigations. As first application, the fluorescence lifetime of two differing conformations of 2-(2′-hydroxyphenyl) benzothiazole is measured.

In the search for scintillators that have a faster response than existing ones, better knowledge on the processes that take place during the first 100 ps of the scintillation process is required. For that one needs detailed information on the intrinsic rise time of a scintillation pulse. However, the observed rise time, also of direct importance to the timing resolution, is strongly affected by the time spread of photons leaving the scintillator. In this work we pioneered the use of a 120 fs Ti-sapphire laser in combination with a streak camera system to measure those photon time spreads with time resolution up to 5 ps. With this setup the photon time spread distributions of scintillator crystals with different size and/or surface treatment were measured. The potential to study the effect of Teflon packaging on this distribution was also investigated.

A further performance test of a fluorescence lifetime spectroscopy system with 2D-photon counting based on a streak camera was carried out. This system offers three different excitation light sources. It includes a pulsable X-ray tube with 40 kV and a laser. A pulsed UV-LED has been installed for sample excitation. The table top measurement device has a temporal resolution down to 20 ps after deconvolution and fluorescence/scintillation decay times can be evaluated in a wavelength selectable range between 200 and 850 nm. Cesium fluoride, cesium chloride and cesium bromide as fast core-valence luminescence emitters with a relatively low light yield were used in the presented performance test. The easily manageable system is able to detect low light levels and to determine the decay times in agreement with literature in most instances. Beside mentioned scintillators PbCO 3 , SrI 2 and Lu 2 SiO 5 :Ce as a high light yield material were also measured.

Temporal parameters of synchrotron pulse radiation at damping ring (DP) installation of VEPP-5 type were measured with the help of PS-1/S1 picosecond streak camera having 1.5 ps time resolution. These measurements were proceeded within 400-900 nm spectral range. It has been shown that our streak camera may record either a train of electron bunches with ns-duration or internal structure inside a single bunch. We were able to record the distance ~ 1.5 ns between separate bunches as well as their amplitude, which depends on particle numbers inside a bunch. Depending on linear accelerator mode of operation it was possible to define a single bunch duration, which was deviated within the range of 20-100 ps. The temporal structure of a single bunch was measured with 1.5 ps time accuracy. As a result, the VEPP-5 damping ring parameters were optimized, and particles injection conditions were improved. In addition, we have measured the temporal parameters of Vavilov-Cherenkov radiation (VCR) emitted by electron beam of linear accelerator. Our results provided important information on electron bunches formation and their quality inside linear accelerator before electrons injection inside a damping ring. Another series of experiments were done at VEPP-4M electron-positron collider. The dependence of beam length of the beam current measured with streak-camera allowed us to compute the wide-band impedance of the accelerator. The same data were obtained at Siberia-2 synchrotron radiation source (NRC “Kurchatov Institute”, Moscow).

The setup under development is intended to serve as the Russian National Primary Special Standard for Laser Pulse Duration in the range from 10 to 1000 ps. The core components of the standard are a streak camera with picosecond temporal resolution and a Fabry-Perot etalon illuminated by femtosecond laser pulses. The etalon defines a time interval which is used to calibrate the temporal scale of the streak camera. The standard includes a picosecond laser pulse generator for reproduction and transfer of the unit of laser pulse duration to another measuring instrument or secondary standard. Described are the principles of operation, the construction of the standard, and the results of preliminary experiments to determine its metrological properties.

Measurements of the time-dependent fluorescence depolarization of emissive probe molecules enable real-time observations of molecular rotations in shocked materials. In shocked solids, molecular rotations occur as a result of shear deformations. An apparatus is described to measure time-dependent fluorescence depolarization of shocked materials using laser-driven flyer plates and either a picosecond or a nanosecond probe laser. The emission was separated into parallel and perpendicular channels and imaged onto a streak camera. Time-dependent fluorescence depolarization of rhodamine 6G (R6G) dye dissolved in poly-methyl methacrylate (PMMA) was measured with a 16 ns duration impact at 1 km s−1. A partial depolarization of the dye emission was observed to occur during a 150 ns period after the shock.

A prototype of a picosecond x-ray streak camera has been developed and tested by Commissariat a l’Energie Atomique et aux Energies Alternatives to provide plasma-diagnostic support for the Laser Megajoule. We report on the measured performance of this streak camera, which almost fulfills the requirements: 50-μm spatial resolution over a 15-mm field in the photocathode plane, 17-ps temporal resolution in a 2-ns timebase, a detection threshold lower than 625 nJ/cm2 in the 0.05–15 keV spectral range, and a dynamic range greater than 100.

An ultrafast streaked extreme-ultraviolet (XUV) spectrometer (5–20 nm) was developed to measure the temperature dynamics in rapidly heated samples. Rapid heating makes it possible to create exotic states of matter that can be probed during their inertial confinement time—tens of picoseconds in the case of micron-sized targets. In contrast to other forms of pyrometry, where the temperature is inferred from bulk x-ray emission, XUV emission is restricted to the sample surface, allowing for a temperature measurement at the material–vacuum interface. The surface-temperature measurement constrains models for the release of high-energy-density material. Coupling the XUV spectrometer to an ultrafast (

A high-resolving-power x-ray spectrometer has been developed for the OMEGA EP Laser System based on a spherically bent Si [220] crystal with a radius of curvature of 330 mm and a Spectral Instruments (SI) 800 Series charge-coupled device. The instrument measures time-integrated x-ray emission spectra in the 7.97- to 8.11-keV range, centered on the Cu Kα1 line. To demonstrate the performance of the spectrometer under high-power conditions, Kα1,2 emission spectra were measured from Cu foils irradiated by the OMEGA EP laser with 100-J, 1-ps pulses at focused intensities above 1018 W/cm2. The ultimate goal is to couple the spectrometer to a picosecond x-ray streak camera and measure temperature-equilibration dynamics inside rapidly heated materials. The plan for these ultrafast streaked x-ray spectroscopy studies is discussed.

Streak cameras are widely used to record the spatio-temporal evolution of laser-induced plasma. A prototype of picosecond X-ray streak camera has been developed and tested by Commissariat a l’Energie Atomique et aux Energies Alternatives to answer the Laser MegaJoule specific needs. The dynamic range of this instrument is measured with picosecond X-ray pulses generated by the interaction of a laser beam and a copper target. The required value of 100 is reached only in the configurations combining the slowest sweeping speed and optimization of the streak tube electron throughput by an appropriate choice of high voltages applied to its electrodes.

We have employed time-resolved X-ray diffraction with picosecond temporal resolution to measure the time-dependent rocking curves of laser-irradiated asymmetrically cut single InSb crystals. Coherent acoustic phonons were excited in the crystals by irradiation with 800-nm, 100-fs laser pulses at irradiances between 0.25 and 12 mJ/cm2. The induced time-dependent strain profiles (corresponding to the coherent phonons) were monitored by diffracting collimated, monochromatic pulses of X-rays from the irradiated crystals. Recording of the diffracted radiation with a fast low-jitter X-ray streak camera resulted in an overall temporal resolution of better than 2 ps. The strain associated with the coherent phonons modifies the rocking curve of the crystal in a time-dependent manner, and the rocking curve is recorded by keeping the angle of incidence of the X-rays upon the crystal fixed, but varying the energy of the incident X-rays around a central energy of 8.453 keV (corresponding to the peak of the rocking curve of the unperturbed crystal). The observed time-dependent diffraction from the irradiated crystals is in reasonable agreement with simulations over a wide range of energies from the unperturbed rocking-curve peak.

A table top picosecond pulsed X-ray and laser induced fluorescence spectrometer using two-dimensional photon counting is presented. With this streak camera system it is possible to measure fluorescence events in a wavelength range from 200-850 nm. Measuring results are full time resolved fluorescence spectra with a temporal resolution up to 20 ps after deconvolution. The instrumental response function (IRF) of the system is around 60 ps for laser excitation and 80 ps for X-ray excitation. For a performance test well known inorganic (CsI, CsI:Tl) and organic scintillators (anthracene) as well as rhodamine 6G for laser induced fluorescence are measured and evaluated. The easily manageable system shows satisfying results in agreement with literature values.

Time-resolved laser-induced fluorescence (TR-LIF) and the laser induced breakdown spectroscopy (LIBS) have been shown to be methods which are fast and sensitive to provide information about the constituents in analyzed samples. TR-LIF and LIBS have similar hardware requirements. In this paper, we analyze some characteristics of TR-LIF/LIBS system implemented in our laboratory, considering the fact that the excitation part of the system is based on Nd:YAG laser and Optical Parametric Oscillator (OPO). The laser is more than powerful enough (365 mJ at 1064 nm, variable OPO output >5 mJ) for LIBS, but somehow slow (the length of fundamental laser harmonic output pulse is about 5 ns) for fluorescence measurements in our present area of interest, namely plants and food products. Fortunately, the pulse length of tunable OPO output (320–475 nm) is less then 1 ns, so by means of a correct deconvolution procedure it is possible to measure the fluorescence lifetimes in the range as small as a few nanoseconds. The fluorescence detection part of our system is based on picosecond streak camera. Using the fluorescent dyes (Rhodamine B and Fluorescein) ethanol solutions we verified the analyzing capabilities of our TR-LIF system.

An exponential doping NEA InGaAs photocathode is theoretically proposed to apply in the near infrared streak camera. The photocathode time response is calculated and analyzed by using a photoelectron non-steady method. The numerical results show that the excited electrons in the InGaAs active layer is accelerated due to the built-in electric field induced by the exponential doping structure, which shortens the transport time of minority carriers in the photocathode and thus, the time response is greatly improved. In addition, the exponential doping InGaAs photocathode possesses time response of less than 10 picoseconds and near-infrared quantum efficiency of 10%.

Errors of measuring time dependences of the light intensities of picosecond laser pulses by two electron-optical systems are studied. The first system is the picosecond streak camera made in Russia, and the second system, designed in Germany, consists of a picosecond streak camera coupled with a double spec-trograph. The manufacturers test similar systems by using femtosecond pulses, however, this does not allow one to predict errors of measuring picosecond pulses. Parameters that characterize just these errors are proposed and measured. Their behavior is determined, when the amplitude (energy) of the measured pulses increases, and the influence of the cross-section shape of the light beam on the measurement accuracy is studied.

To design new scintillating materials, it is very important to understand detailed information about the events, which occurred during the excitation and emission processes under the ionizing radiation excitation. We developed a streak camera system equipped with picosecond pulsed X-ray source to observe time- and wavelength-resolved scintillation events. In this report, we test the performance of this new system using several types of scintillators including bulk oxide/halide crystals, transparent ceramics, plastics and powders. For all samples, the results were consistent with those reported previously. The results demonstrated that the developed system is suitable for evaluation of the scintillation properties.

A PS-1/S1 picosecond image-tube streak camera (ITSC) with slit scan (streak camera), developed and manufactured at the General Physics Institute RAS, has been used to measure the spatiotemporal characteristics of ultrashort laser pulses generated by a petawatt-power laser installation 'FEMTO' at the Institute of Laser Physics Research in Sarov. It is found that such a camera is suitable for measuring the spatial and temporal parameters of single laser pulses with an accuracy of about one picosecond. It is shown that the intensity time profile of a train of picosecond pulses may be precisely defined for the pulses separated in time by a few picoseconds. The camera allows the contrast of radiation to be determined with a high (no less than 103) accuracy; spatial distribution of the laser pulses can be measured with an accuracy of tens of microns, and the temporal separation of single laser pulses can be identified with an accuracy of 1 – 1.5 ps.

The time dependence of the X-ray intensity from targets exposed to single-shot or successive picosecond laser pulses at the NEODIM facility was obtained by direct measurements. The measurements were taken using an CXP8 streak camera (produced by the Research Institute of Pulse Techniques) with a picosecond time resolution under different operating conditions of the facility. The observed X-ray pulses had a half-height duration of 15–50 ps and a rise time of 5 ps at a ∼1.5-ps duration of the effecting laser pulse. Under actual experimental conditions, it was ascertained that time dependences of the X-ray intensity could be recorded for more than 200 spatial elements on a single record at a sweep duration of 0.5 ns per frame and a time resolution of

A new streak camera with more wider dynamic range and picosecond temporal resolution for soft X-ray was developed.The photocathode′s working area is 30 mm in diameter,and its focusing voltage is reduced to 8 kV to prevent electrical discharge.A post-accelaration system was introduced into the image tube for improving the phosphor screen′s quantum efficiency largely,and an external image intensifier with wide dynamic range was adopted.Experimental evaluation was carried out by means of a picosecond laser,and the results show that the dynamic range of more than 2000 can be achieved.

A technique for registering the temporal structure of picosecond pulses of CO2 laser radiation with an energy of 1.5–4.5 μJ at a wavelength of 10.27 μm using two-stage parametric transformation of IR radiation frequency into visible light under pumping of nonlinear crystals by Nd:YAG-laser radiation in a Q-switched mode is described. A GaSe nonlinear crystal was used at the first stage of transformation (10.27 μm + 1.064 μm → 0.964 μm). Radiation was further transformed (1.064 μm + 0.960 μm → 0.506 μm) by using the same pumping in an α-HIO3 nonlinear crystal. For the first time, no additional optical elements were present between the stages of the frequency transformer in the proposed optical scheme. The transformed radiation was registered with a Hamamatsu Temporal Disperser C1587 streak camera in a region of the photocathode maximum spectral sensitivity of ∼0.5 μm with a temporal resolution of up to 2 ps. The minimum recorded pulse duration of the CO2 laser was ∼45 ps.

We present an experimental technique, which allows us to determine the second order correlation function g(2) (t, t + τ) with picosecond time resolution. The method involves a streak camera which is modified such that a signal at fixed wavelength can be monitored after each pulsed laser excitation. From these measurements insight into the quantum optical properties of light emission from semiconductor nanostructures with dynamics on the sub-ns time scale can be taken. To demonstrate the possibilities of our setup, we present time resolved g(2)-measurements of quantum dot VCSEL micropillar emission. We show, that our measurement scheme enables us to determine the transition from predominantly spontaneous emission towards stimulated emission and the temporal evolution of the intensity correlation function. Additionally, we are also able to identify unexpected features like dynamical antibunching. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The fluorescence spectra of three different dyes adsorbed on the tabular and cubic AgBr microcrystals are obtained by the picosecond time-resolved streak camera technique. The dependence of the ultrafast electron transferring from dye-aggregates to the conduction band of AgBr and the efficiency of spectral sensitization on different kinds of dyes with different concentrations is analyzed. Further more, the microcosmic mechanism of the sensitization process is discussed. It is found that the fluorescence decay curves are fitted very well by the double exponential function, consisting of a slow component and a fast one with large amplitude. We consider this fast one mainly attributable to the electron transfer from dye J-aggregates to the conduction band of AgBr.