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Publisher: Springer-Verlag   (Total: 2355 journals)

 Applied Physics B: Lasers and Optics   [SJR: 0.983]   [H-I: 104]   [23 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 0946-2171 - ISSN (Online) 1432-0649    Published by Springer-Verlag  [2355 journals]
• Selective detection of intermolecular response in benzonitrile through
double-pulse excitation in optical Kerr effect spectroscopy
• Authors: V. G. Nikiforov; D. K. Zharkov; A. G. Shmelev; A. V. Leontyev; V. S. Lobkov
Abstract: We report on the decomposition of the molecular contribution to the optically heterodyne-detected optical Kerr effect (OHD-OKE) in benzonitrile C6H5CN in the process of double-pulse laser excitation. The pump pulses with linear orthogonal polarizations, controllable intensities and timing enable us to manipulate the amplitudes of various molecular responses due to the fact that the OHD-OKE signal is formed by the superposition of independent third-order responses associated with each pump pulse. We apply this technique to detect the intermolecular response selectively by using an excitation scenario with suppression of orientational and intramolecular responses. A detailed comparative analysis of third-order optical responses indicates strongly that the double-pulse excitation of the OHD-OKE is the useful spectroscopic technique to obtain precise information on the intermolecular spectrum in liquids.
PubDate: 2017-07-07
DOI: 10.1007/s00340-017-6788-6
Issue No: Vol. 123, No. 7 (2017)

• Self-orientation effect of liquid crystals on holographic
polymer-dispersed liquid crystal and distributed feedback lasers
• Authors: Minghuan Liu; Yonggang Liu; Zenghui Peng; Haifeng Zhao; Zhaoliang Cao; Li Xuan
Abstract: The average orientation of a liquid crystal (LC) director to the grating formation, morphology, and switching properties of a holographic polymer-dispersed liquid crystal (HPDLC) grating was systematically investigated in this study. The grating possessed high diffraction efficiency and low scattering with the LC director being parallel to the grating vector. The scanning electron microscope confirmed the well-defined morphology with the LC director being parallel to the grating vector. The grating was easily switched when the LC director was perpendicular to the grating vector. Moreover, polarization excitation was performed to investigate the polarization dependence behavior of the HPDLC-distributed feedback (DFB) laser. The results confirmed that the HPDLC grating is suitable as a laser oscillation when the LC director is parallel to the grating vector. Finally, the tuning range was obtained for the HPDLC DFB laser by applying an external electric field. The tunability, ease of fabrication, and mass production make the HPDLC DFB lasers suitable as smart laser sources for spectroscopy and communication.
PubDate: 2017-07-05
DOI: 10.1007/s00340-017-6786-8
Issue No: Vol. 123, No. 7 (2017)

• Narrow-line external cavity diode laser micro-packaging in the NIR and MIR
spectral range
• Authors: A. Jiménez; T. Milde; N. Staacke; C. Aßmann; G. Carpintero; J. Sacher
Abstract: Narrow-linewidth tunable diode lasers are an important tool for spectroscopic instrumentation. Conventional external cavity diode lasers offer high output power and narrow linewidth. However, most external cavity diode lasers are designed as laboratory instrument and do not allow portability. In comparison, other commonly used lasers, like distributed feedback lasers (DFB) that are capable of driving a handheld device, are limited in power and show linewidths which are not sufficiently narrow for certain applications. We present new miniaturized types of tunable external cavity diode laser which overcome the drawbacks of conventional external cavity diode lasers and which preserve the advantages of this laser concept. Three different configurations are discussed in this article. The three types of miniaturized external cavity diode laser systems achieve power values of more than 50 mW within the 1.4 $$\mu$$ m water vapor absorption band with excellent side-mode suppression and linewidth below 100 kHz. Typical features outstand with respect to other type of laser systems which are of extended use such as DFB laser diodes. The higher output power and the lower linewidth will enable a higher sensitivity and resolution for a wide range of applications.
PubDate: 2017-07-04
DOI: 10.1007/s00340-017-6777-9
Issue No: Vol. 123, No. 7 (2017)

• Optical and structural properties of Nd:MgO:LiNbO 3 crystal irradiated by
2.8-MeV He ions
• Authors: Chuan-Lei Jia; Song Li; Xiao-Xiao Song
Abstract: We report the optical and structural properties of helium-implanted optical waveguides in Nd:MgO:LiNbO3 laser crystals. The prism-coupling method is used to investigate the dark-mode properties at the wavelength of 632.8 nm. The spontaneous generation of ultraviolet, blue, red, and near-infrared fluorescence emissions is demonstrated under excitation with an 808-nm laser diode. The effects of ion irradiation on the structural properties are characterized using the high-resolution X-ray diffraction technique. The results show that the initial luminescence properties of Nd:MgO:LiNbO3 crystals are slightly modified by irradiation with 2.8 MeV He ions at fluences of 1.5 × 1016 ions/cm2 at room temperature.
PubDate: 2017-07-03
DOI: 10.1007/s00340-017-6783-y
Issue No: Vol. 123, No. 7 (2017)

• Measurement of the absolute absorbance based on wavelength modulation
spectroscopy
• Authors: Yanjun Du; Lijuan Lan; Yanjun Ding; Zhimin Peng
Abstract: Ratios of the 2nd and 1st harmonics at the line center are very sensitive to absorbance, but not to line profiles when the modulation index is set to 0.94. Based on this characteristic, we proposed a method which uses the 1st and 2nd harmonics to measure the absolute absorbance, and then obtain gas pressure and concentration. Some transitions of CO2 and H2O molecules near 6980 cm−1 are selected to verify this method. The satisfactory agreement between measurement results and theoretical values validates the proposed method.
PubDate: 2017-06-28
DOI: 10.1007/s00340-017-6780-1
Issue No: Vol. 123, No. 7 (2017)

• Energetic metallic ion implantation in polymers via cost-effective
laser-driven ion source
• Authors: Muhammad Bilal Tahir; M. Shahid Rafique; Rabia Ahmed; M. Rafique; Tahir Iqbal; Ali Hasan
Abstract: This research work reports the ions emission from the plasma generated by Nd:YAG laser having wavelength 1.064 μm, power 1.1 MW, pulse energy 10 mJ and intensity 1011 W/cm2 irradiated at 70° with respect to the target normal to the ions. These ions were accelerated through a home-made extraction assembly by means of a high voltage DC power supply. The energy of these ions were measured using Thomson parabola technique which utilizes Solid State Nuclear Track Detector (CR-39) and confirmed by Faraday cup as well that exploits a well-known technique known as time of flight. Interestingly, a significant increase in energy (from 490 to 730 keV) was observed with a discrete increase in acceleration potential from 0 to 18 kV. Polyethylene terephthalate (PET) and polypropylene were exposed to this recently developed ion source facility, to authenticate the reliability of this facility. The surface of the polymer is affected when energy of the irradiated ion is increased, which is evident from the optical micrographs. An increase in electrical conductivity was also observed with the increase in ion energy.
PubDate: 2017-06-28
DOI: 10.1007/s00340-017-6762-3
Issue No: Vol. 123, No. 7 (2017)

• The blue light indicator in rubidium 5S–5P–5D cascade
excitation
• Authors: Waseem Raja; Md. Sabir Ali; Alok Chakrabarti; Ayan Ray
Abstract: The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump–probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon–atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits ~420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.
PubDate: 2017-06-23
DOI: 10.1007/s00340-017-6778-8
Issue No: Vol. 123, No. 7 (2017)

• Role of target thickness in proton acceleration from near-critical
mass-limited plasmas
• Authors: Deep Kumar Kuri; Nilakshi Das; Kartik Patel
Abstract: The role played by the target thickness in generating high energetic protons by a circularly polarized laser from near-critical mass-limited targets (MLT) has been investigated with the help of three-dimensional (3D) particle-in-cell (PIC) simulations. The radiation pressure accelerates protons from the front side of the target. Due to hole boring, the target front side gets deformed resulting in a change in the effective angle of incidence which causes vacuum heating and hence generates hot electrons. These hot electrons travel through the target at an angle with the laser axis and hence get more diverged along transverse directions for large target thickness. The hot electrons form sheath fields on the target rear side which accelerates protons via target normal sheath acceleration (TNSA). It is observed that the collimation of radiation pressure accelerated protons gets degraded on reaching the target rear side due to TNSA. The effect of transverse hot electron recirculations gets suppressed and the energetic protons get highly collimated on decreasing target thickness as the radiation pressure acceleration (RPA) starts dominating the acceleration process.
PubDate: 2017-06-23
DOI: 10.1007/s00340-017-6779-7
Issue No: Vol. 123, No. 7 (2017)

• Parametric Raman crystalline anti-Stokes laser at 503 nm with collinear
beam interaction at tangential phase matching
• Authors: S. N. Smetanin; M. Jelínek; V. Kubeček
Abstract: Stimulated-Raman-scattering in crystals can be used for the single-pass frequency-conversion to the Stokes-shifted wavelengths. The anti-Stokes shift can also be achieved but the phase-matching condition has to be fulfilled because of the parametric four-wave mixing process. To widen the angular-tolerance of four-wave mixing and to obtain high-conversion-efficiency into the anti-Stokes, we developed a new scheme of the parametric Raman anti-Stokes laser at 503 nm with phase-matched collinear beam interaction of orthogonally-polarized Raman components in calcite oriented at the phase-matched angle under 532 nm 20 ps laser excitation. The excitation laser beam was split into two orthogonally-polarized components entering the calcite at the certain incidence angles to fulfill the nearly collinear phase-matching and also to compensate walk-off of extraordinary waves for collinear beam interaction. The phase matching of parametric Raman interaction is tangential and insensitive to the angular mismatch if the Poynting vectors of the biharmonic pump and parametrically generated (anti-Stokes) waves are collinear. For the first time it allows to achieve experimentally the highest conversion efficiency into the anti-Stokes wave (503 nm) up to 30% from the probe wave and up to 3.5% from both pump and probe waves in the single-pass picosecond parametric calcite Raman laser. The highest anti-Stokes pulse energy was 1.4  $$\upmu$$ J.
PubDate: 2017-06-23
DOI: 10.1007/s00340-017-6776-x
Issue No: Vol. 123, No. 7 (2017)

• An optical multimode fiber as pseudothermal light source
• Authors: Thomas Mehringer; Steffen Oppel; Joachim von Zanthier
Abstract: We report on a novel pseudothermal light source based on laser light coupled into an optical multimode fiber. The setup is simple, low cost, exhibits inherently high directional light emission and allows for a flexible arrangement. By measuring the photon statistics and spatial two point intensity correlations in the far field we show that the setup exhibits all characteristics of a Gaussian random source.
PubDate: 2017-06-20
DOI: 10.1007/s00340-017-6775-y
Issue No: Vol. 123, No. 7 (2017)

• Predicting fluorescence quantum yield for anisole at elevated temperatures
and pressures
• Authors: Q. Wang; K. H. Tran; C. Morin; J. Bonnety; G. Legros; P. Guibert
Abstract: Aromatic molecules are promising candidates for using as a fluorescent tracer for gas-phase scalar parameter diagnostics in a drastic environment like engines. Along with anisole turning out an excellent temperature tracer by Planar Laser-Induced Fluorescence (PLIF) diagnostics in Rapid Compression Machine (RCM), its fluorescence signal evolution versus pressure and temperature variation in a high-pressure and high-temperature cell have been reported in our recent paper on Applied Phys. B by Tran et al. Parallel to this experimental study, a photophysical model to determine anisole Fluorescence Quantum Yield (FQY) is delivered in this paper. The key to development of the model is the identification of pressure, temperature, and ambient gases, where the FQY is dominated by certain processes of the model (quenching effect, vibrational relaxation, etc.). In addition to optimization of the vibrational relaxation energy cascade coefficient and the collision probability with oxygen, the non-radiative pathways are mainly discussed. The common non-radiative rate (intersystem crossing and internal conversion) is simulated in parametric form as a function of excess vibrational energy, derived from the data acquired at different pressures and temperatures from the literature. A new non-radiative rate, namely, the equivalent Intramolecular Vibrational Redistribution or Randomization (IVR) rate, is proposed to characterize anisole deactivated processes. The new model exhibits satisfactory results which are validated against experimental measurements of fluorescence signal induced at a wavelength of 266 nm in a cell with different bath gases (N2, CO2, Ar and O2), a pressure range from 0.2 to 4 MPa, and a temperature range from 473 to 873 K.
PubDate: 2017-06-17
DOI: 10.1007/s00340-017-6773-0
Issue No: Vol. 123, No. 7 (2017)

• Characterization of the coherence properties of different optical sources
• Authors: A. Celine Kavida; A. Roberts
Abstract: Non-interferometric phase-space tomography is used to characterize the spatial coherence properties of scalar quasi-monochromatic partially coherent optical fields. Three sources were investigated and characteristic projections through the correlation functions determined. It was seen that a single-mode fibre-coupled source exhibited a much longer coherence length than a multi-mode fibre-coupled source. Both sources exhibited a high degree of symmetry. A collimated light emitted diode, on the other hand, was shown to have a short spatial coherence length and clear asymmetries were evident.
PubDate: 2017-06-16
DOI: 10.1007/s00340-017-6769-9
Issue No: Vol. 123, No. 7 (2017)

• The effect of laser contrast on generation of highly charged Fe ions by
ultra-intense femtosecond laser pulses
• Authors: Anatoly Ya. Faenov; Maria A. Alkhimova; Tatiana A. Pikuz; Igor Yu. Skobelev; Mamiko Nishiuchi; Hironao Sakaki; Alexander S. Pirozhkov; Akito Sagisaka; Nicholas P. Dover; Kotaro Kondo; Koichi Ogura; Yuji Fukuda; Hiromitsu Kiriyama; Alexander Andreev; Keita Nishitani; Takumi Miyahara; Yukinobu Watanabe; Sergey A. Pikuz; Masaki Kando; Ruosuke Kodama; Kiminori Kondo
Abstract: Experimental studies on the formation of highly charged ions of medium-Z elements using femtosecond laser pulses with different contrast levels were carried out. Multiply charged Fe ions were generated by laser pulses with 35 fs duration and an intensity exceeding 1021 W/cm2. Using high-resolution X-ray spectroscopic methods, bulk electron temperature of the generated plasma has been identified. It is shown that the presence of a laser pre-pulse at a contrast level of 105–106 with respect to the main pulse drastically decreases the degree of Fe ionization. We conclude that an effective source of energetic, multiply charged moderate and high-Z ions based on femtosecond laser–plasma interactions can be created only using laser pulses of ultra-high contrast.
PubDate: 2017-06-15
DOI: 10.1007/s00340-017-6771-2
Issue No: Vol. 123, No. 7 (2017)

• High-beam-quality, efficient operation of passively Q-switched
Yb:YAG/Cr:YAG laser pumped by photonic-crystal surface-emitting laser
• Authors: Xiaoyang Guo; Shigeki Tokita; Kana Fujioka; Hiro Nishida; Kazuyoshi Hirose; Takahiro Sugiyama; Akiyoshi Watanabe; Kenji Ishizaki; Susumu Noda; Noriaki Miyanaga; Junji Kawanaka
Abstract: A passively Q-switched Yb:YAG/Cr:YAG laser pumped by a photonic-crystal surface-emitting laser (PCSEL) was developed. Yb:YAG crystal was cryogenically cooled by liquid nitrogen at 77 K. Excellent Gaussian beam profile (M 2 = 1.02) and high slope efficiency of 58% were demonstrated without using a coupling optics between a laser material and PCSEL.
PubDate: 2017-06-15
DOI: 10.1007/s00340-017-6772-1
Issue No: Vol. 123, No. 7 (2017)

• Surface-tuned three-photon absorption of CdSe nanocrystals in
near-infrared
• Authors: Chong Wang; Fangfang Wang; Baohua Zhu; Shuxi Dai; Yuzong Gu; Jiayu Zhang
Abstract: We studied the tunable three-photon absorption (3PA) response of colloidal CdSe nanocrystals in near-infrared by surface states which were successfully controlled with a purification process. The 3PA cross section at room temperature was decreased by more than two orders of magnitude when the density of surface traps increases and works through the photoinduced and intrinsic dipole moments of excitons, indicating that the surface-tuned three-photon absorption of CdSe was of significance in potential applications.
PubDate: 2017-06-15
DOI: 10.1007/s00340-017-6768-x
Issue No: Vol. 123, No. 7 (2017)

• Three-dimensional light bullets in a Bragg medium with carbon nanotubes
• Authors: Alexander V. Zhukov; Roland Bouffanais; Mikhail B. Belonenko; Ilya S. Dvuzhilov; Yulia V. Nevzorova
Abstract: We present a theoretical study of the propagation of three-dimensional extremely short electromagnetic pulses (a.k.a. light bullets) through a Bragg medium containing an immersed array of carbon nanotubes. We demonstrate the possible stable propagation of such light bullets. In particular, our results suggest these light bullets can carry information about the Bragg medium itself.
PubDate: 2017-06-15
DOI: 10.1007/s00340-017-6767-y
Issue No: Vol. 123, No. 7 (2017)

• Acetone photophysics at 282 nm excitation at elevated pressure and
temperature. II: Fluorescence modeling
• Authors: Jason Hartwig; Mandhapati Raju; Chih-Jen Sung
Abstract: This is the second in a series of two papers that presents an updated fluorescence model and compares with the new experimental data reported in the first paper, as well as the available literature data, to extend the range of acetone photophysics to elevated pressure and temperature conditions. This work elucidates the complete acetone photophysical model in terms of each and every competing radiative and non-radiative rate. The acetone fluorescence model is then thoroughly examined and optimized based on disparity with recently conducted elevated pressure and temperature photophysical calibration experiments. The current work offers insight into the competition between non-radiative and vibrational energy decay rates at elevated temperature and pressure and proposes a global optimization of model parameters from the photophysical model developed by Thurber (Acetone Laser-Induced Fluorescence for Temperature and Multiparameter Imaging in Gaseous Flows. PhD thesis, Stanford University Mechanical Engineering Department, 1999). The collisional constants of proportionality, which govern vibrational relaxation, are shown to be temperature dependent at elevated pressures. A new oxygen quenching rate is proposed which takes into account collisions with oxygen as well as the oxygen-assisted intersystem crossing component. Additionally, global trends in ketone photophysics are presented and discussed.
PubDate: 2017-06-14
DOI: 10.1007/s00340-017-6770-3
Issue No: Vol. 123, No. 7 (2017)

• X-ray emission from a liquid curtain jet when irradiated by femtosecond
laser pulses
• Authors: F. Valle Brozas; D. Papp; L. M. Escudero; L. Roso; A. Peralta Conde
Abstract: Laser-based sources of ionizing radiation have attracted considerable attention in the last years for their broad potential applications. However, the stability and robustness of such sources are still issues that need to be addressed. Aiming to solve such problems, we propose a source that uses a liquid jet—rather than a solid—as a target for the production of X-rays. Liquid jets offer always a clean surface for every laser shot which represent a clear advantage over solids. In this work, we present an experimental characterization of the X-ray emission of such targets, and study the efficiency of the process when two temporally delayed pulses are used. According to the obtained results, the X-ray yield is comparable with commonly used targets.
PubDate: 2017-06-13
DOI: 10.1007/s00340-017-6763-2
Issue No: Vol. 123, No. 6 (2017)

• Acetone photophysics at 282 nm excitation at elevated pressure and
temperature. I: absorption and fluorescence experiments
• Authors: Jason Hartwig; Gaurav Mittal; Kamal Kumar; Chih-Jen Sung
Abstract: This is the first in a series of two papers that presents new experimental data to extend the range of acetone photophysics to elevated pressure and temperature conditions. In this work, a flexible static and flow system is designed and characterized to study the independent as well as coupled effect of elevated pressure and temperature on acetone photophysics over pressures of 0.05‒4.0 MPa and temperatures of 295‒750 K for 282 nm excitation wavelength in nitrogen and air as bath gases. Experimental results show that at 282 nm excitation, relative fluorescence quantum yield increases with increasing pressure, decreases with increasing temperature, and that the pressure sensitivity varies weakly with elevated temperature. The previously assumed linearity of fluorescence with tracer number density is shown to only be valid over a small range. Additionally, acetone fluorescence is only moderately quenched in the presence of oxygen. The present findings yield insight into the competition between the non-radiative and collisional rates at elevated temperature and pressure, as well as provide validation datasets for an updated fluorescence model developed in the second paper.
PubDate: 2017-06-13
DOI: 10.1007/s00340-017-6774-z
Issue No: Vol. 123, No. 6 (2017)

• Even-parity autoionizing levels of atomic uranium and their total angular
momenta
• Authors: P. K. Mandal; A. C. Sahoo; R. C. Das; M. L. Shah; Vas Dev
Abstract: Employing three-colour three-step resonance ionization spectroscopy, photoionization spectra of atomic uranium have been investigated extensively in the energy region 49,959–51,504 cm−1. A detailed analysis of the photoionization spectra has resulted in the observation of 346 even-parity autoionizing levels including 199 new levels and a Rydberg series converging to the second-lowest ionic level ( $${}^{6}{\text{L}}_{11/2}^{\text{o}}$$ ) of uranium. Using the method of laser polarization combinations as well as the method of total angular momentum (J) selection rules, the J values of 72 of these autoionizing levels have been assigned unambiguously. Out of these 72 levels, the unique J values of 56 autoionizing levels have been determined for the first time, while it has been confirmed for the remaining 16 reported previously.
PubDate: 2017-06-13
DOI: 10.1007/s00340-017-6765-0
Issue No: Vol. 123, No. 6 (2017)

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