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Publisher: Springer-Verlag (Total: 2353 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  [2353 journals]
• Q-switching of an all-fiber ring laser based on in-fiber acousto-optic
bandpass modulator
• Authors: G. Ramírez-Meléndez; M. Bello-Jiménez; O. Pottiez; L. Escalante-Zarate; R. López-Estopier; B. Ibarra-Escamilla; M. Durán-Sánchez; E. A. Kuzin; M. V. Andrés
Abstract: Abstract Active Q-switching of an all-fiber ring laser utilizing a novel in-fiber acousto-optic tunable bandpass filter (AOTBF) is reported. The transmission characteristics of the AOTBF are controlled by amplitude modulation of the acoustic wave; the device exhibits a 3-dB power insertion loss, 0.91-nm optical bandwidth, and 28-dB nonresonant light suppression. Cavity loss modulation is achieved by full acousto-optic mode re-coupling cycle induced by traveling flexural acoustic waves. When the acoustical signal is switched on, cavity losses are reduced, and then, laser emission is generated. In addition, by varying the acoustic wave frequency, a wide wavelength tuning range of 30.7 nm is achieved from 1542 to 1572.7 nm. The best Q-switched pulses were obtained at 1.1-kHz repetition rate, with a pump power of 242 mW, at the optical wavelength of 1569.4 nm. A maximum pulse energy of 8.3 μJ at an average output power of 9.3 mW was achieved, corresponding to optical pulses of 7.8-W peak power and 1-μs temporal width.
PubDate: 2017-09-13
DOI: 10.1007/s00340-017-6828-2
Issue No: Vol. 123, No. 9 (2017)

• Sensitive measurement of optical nonlinearity using an absorptive phase
object
• Authors: Yong Yang; Jun-Yi Yang; Zhong-Guo Li; Xing-Zhi Wu; Ying-Lin Song
Abstract: Abstract We report on a modified nonlinear optical measurement technique using an absorptive phase object (PO) to characterize weak optical refraction nonlinearities. The absorptive PO consists of a circular silica substrate on which a dielectric plate has been deposited. The inner dielectric plate simultaneously introduces a π/2 phase shift and changes the amplitude of the incident light. We demonstrate that the measurement sensitivity can be enhanced with the transmittance of the absorptive PO. Experimental and simulation results are presented to validate our approach.
PubDate: 2017-09-12
DOI: 10.1007/s00340-017-6825-5
Issue No: Vol. 123, No. 9 (2017)

• Flame imaging using planar laser induced fluorescence of sulfur dioxide
• Authors: Rene Honza; Carl-Philipp Ding; Andreas Dreizler; Benjamin Böhm
Abstract: Abstract Laser induced fluorescence of sulfur dioxide (SO2-PLIF) has been demonstrated as a useful tool for flame imaging. Advantage was taken from the strong temperature dependence of the SO2 fluorescence signal. SO2 fluorescence intensity increases by more than one order of magnitude if the temperature changes from ambient conditions to adiabatic flame temperatures of stoichiometric methane–air flames. This results in a steep gradient of SO2-PLIF intensities at the reaction zone and therefore can be used as a reliable flame marker. SO2 can be excited electronically using the fourth-harmonic of an Nd:YAG laser at 266 nm. This is an attractive alternative to OH-LIF, a well-recognized flame front marker, because no frequency-doubled dye lasers are needed. This simplifies the experimental setup and is advantageous for measurements at high repetition rates where dye bleaching can become an issue. To prove the performance of this approach, SO2-PLIF measurements were performed simultaneously with OH-PLIF on laminar premixed methane-air Bunsen flames for equivalence ratios between 0.9 and 1.25. These measurements were compared to 1D laminar flamelet simulations. The SO2 fluorescence signal was found to follow the temperature rise of the flame and is located closer to the steep temperature gradient than OH. Finally, the combined SO2- and OH-PLIF setup was applied to a spark ignition IC-engine to visualize the development of the early flame kernel.
PubDate: 2017-09-06
DOI: 10.1007/s00340-017-6823-7
Issue No: Vol. 123, No. 9 (2017)

• An open-path tunable diode laser absorption spectrometer for detection of
carbon dioxide at the Bonanza Creek Long-Term Ecological Research Site
• Authors: D. Michelle Bailey; Erin M. Adkins; J. Houston Miller
Abstract: Abstract We have developed a low-power, open-path, near-infrared (NIR) tunable diode laser sensor for the measurement of near ground-level concentrations of greenhouse gases. Here, we report on instrument design, characterization, and initial measurements of carbon dioxide concentrations during deployment to a thermokarst collapse scar bog near Fairbanks, AK (USA). The optics “launch-box” portion of the instrument couples radiation from an NIR, distributed feedback diode laser operating near 1572 nm with a visible laser for alignment purposes. The outgoing beam is directed through a 3.2-mm hole in a parabolic mirror and the launch-box is oriented using a two axis, altitude-azimuth telescope mount such that the beam strikes a retroreflector target at a set distance downfield. The beam then retraces the path back to the launch-box where the light is collected on the surface of the parabolic mirror and focused onto a multimode fiber that transfers the radiation to an InGaAs detector. Sweeps over a ~1.6 cm−1 spectral region were collected at a rate of 500 scans per second and were typically stored as 10 s sweep averages. These averaged sweeps could be individually spectrally fit for CO2 concentration or averaged into a single spectrum for fitting (after correction for slight frequency drift). Field data reported here was averaged for 2.5 min and was found to follow trends in diurnal cycles of CO2 concentration cycles reported by sensors located nearby in the field site.
PubDate: 2017-09-06
DOI: 10.1007/s00340-017-6814-8
Issue No: Vol. 123, No. 9 (2017)

• The SPIRIT airborne instrument: a three-channel infrared absorption
spectrometer with quantum cascade lasers for in situ atmospheric trace-gas
measurements
• Authors: Valéry Catoire; Claude Robert; Michel Chartier; Patrick Jacquet; Christophe Guimbaud; Gisèle Krysztofiak
Abstract: Abstract An infrared absorption spectrometer called SPIRIT (SPectromètre Infra-Rouge In situ Toute altitude) has been developed for airborne measurements of trace gases in the troposphere. At least three different trace gases can be measured simultaneously every 1.6 s using the coupling of a single Robert multipass optical cell with three Quantum Cascade Lasers (QCLs), easily interchangeable to select species depending on the scientific objectives. Absorptions of the mid-infrared radiations by the species in the cell at reduced pressure (<40 hPa), with path lengths adjustable up to 167.78 m, are quantified using an HgCdTe photodetector cooled by Stirling cycle. The performances of the instrument are assessed: a linearity with a coefficient of determination R 2 > 0.979 for the instrument response is found for CO, CH4, and NO2 volume mixing ratios under typical tropospheric conditions. In-flight comparisons with calibrated gas mixtures allow to show no instrumental drift correlated with atmospheric pressure and temperature changes (when vertical profiling) and to estimate the overall uncertainties in the measurements of CO, CH4, and NO2 to be 0.9, 22, and 0.5 ppbv, respectively. In-flight precision (1σ) for these species at 1.6 s sampling is 0.3, 5, and 0.3 ppbv, respectively.
PubDate: 2017-09-05
DOI: 10.1007/s00340-017-6820-x
Issue No: Vol. 123, No. 9 (2017)

• Operation of polarization order of vector beams with cascaded metasurfaces
• Authors: Xunong Yi; Panli Huang; Xiuzhang Huang; Zhaoxin Xu; Chen Zhang; Jun Zhao; Xiaoqing Liu; Yuqian Ai; Huan Chen
Abstract: Abstract Metasurface is an effective tool for smanipulating optical wave and can be used to generate vector beams. In this work, we propose a method to realize the operation of the polarization order of vector beams with cascaded metasurfaces. Employing Jones calculation, we theoretically analyze the transformation of cascaded metasurfaces for linearly polarized incident light. The results show that two directly cascaded metasurfaces can realize the subtraction operation of polarization order of vector beam. When a half-wave plate is inserted between the two metasurfaces, the addition operation of polarization order can be achieved. Lastly, verification experiments are performed. The experimental results are in good agreement with the theoretical predictions.
PubDate: 2017-08-30
DOI: 10.1007/s00340-017-6816-6
Issue No: Vol. 123, No. 9 (2017)

• Fluorescence and absorption characteristics of p -xylene: applicability
for temperature measurements
• Authors: Qianlong Wang; Yuyin Zhang; Liqiao Jiang; Daiqing Zhao; Philippe Guibert; Shunhua Yang
Abstract: Abstract This paper explores the characteristics of absorption and fluorescence spectra of p-xylene within the temperature range that is frequently encountered during the mixture formation in internal combustion engines. At 266 nm wavelength, the p-xylene absorption cross section shows a mean value of (3.4 ± 0.2) × 10−19 cm2/molecule within the temperature range from 423 to 623 K in N2. As expected, fluorescence peak intensity decreases by a factor of 3 when the temperature increases by 100 K, due to a increasing non-radiative decay rate of excited state at increasing temperatures. In addition, the suitability of p-xylene for temperature measurements in the gas phase via the single-wavelength excitation (at 266 nm) two-color detection laser-induced fluorescence imaging is explored. Combinations of spectral detection bands were compared and the combination of 320/289 nm provides the best temperature performance with a relative error of 2.6% within the investigated temperature range. It is also shown that the temperature field measurement has not been strongly affected by the laser attenuation.
PubDate: 2017-08-30
DOI: 10.1007/s00340-017-6817-5
Issue No: Vol. 123, No. 9 (2017)

• Selective photoionization of palladium isotopes using a two-step
excitation scheme
• Authors: Clayton R. Locke; Tohru Kobayashi; Takashige Fujiwara; Katsumi Midorikawa
Abstract: Abstract We present a novel two-step even–odd mass isotope selective excitation and ionization scheme, potentially applicable in resource recycling and management of palladium occurring in high-level nuclear waste. In contrast to the conventional three-step selective ionization process, the two-step scheme utilizes transition selection rules to an autoionizing Rydberg state, rather than to an intermediate state, resulting in an increase in efficiency of over an order of magnitude while retaining excellent selectivity of >99.7%. The reduction in the number of excitation lasers required allows several technical simplifications and reduces costs should the process be developed for large-scale resource recycling operations.
PubDate: 2017-08-29
DOI: 10.1007/s00340-017-6818-4
Issue No: Vol. 123, No. 9 (2017)

• Cascaded multi-dithering technique using PZT modulators for high control
bandwidth in coherent laser beam combining
• Authors: Hee Kyung Ahn; Hong Jin Kong
Abstract: Abstract A cascaded multi-dithering (CMD) technique using piezoelectric ceramic transducer (PZT) tubes as phase modulators is proposed as a tool for obtaining high control bandwidth in coherent laser beam combination. To prove its validity, eight coherent fiber beam elements were combined using the CMD technique with PZT tubes. As a result, residual phase error was recorded to be λ/54 at 100 Hz control bandwidth, which is comparable to that of a four laser beam combination in the previous experiment. To our knowledge, this is the first case to date of combining eight laser beam elements using PZT tubes as phase modulators and achieving such good results.
PubDate: 2017-08-29
DOI: 10.1007/s00340-017-6819-3
Issue No: Vol. 123, No. 9 (2017)

• Crossover from plasmonic analogue of Fano resonance to Autler–Townes
splitting in a double guide mode resonances system
• Authors: Buzheng Wei; Guobin Ren; Shuisheng Jian
Abstract: Abstract The plasmonic analogy from Fano resonance to Autler–Townes splitting (ATS) in mid-infrared spectral range is observed assisted by a dual parallel graphene-coated grating structure. The analytical derivation exhibits a height-dependent resonance which is crucial for discerning Fano resonance from ATS. The mechanism of generating a transparency window seeks a trade-off between Fano resonance and ATS at threshold height. While within the critical height, Fano resonance dominates. The Akaike Information Criterion test is used to discern these two effects quantitatively. Moreover, the device pronounces a good tunability accompanied with a slowing light application. Our ideas open up a new insight view of designing or constructing highly integrated, multi-functional graphene-based metamaterials in nanoscale.
PubDate: 2017-08-28
DOI: 10.1007/s00340-017-6813-9
Issue No: Vol. 123, No. 9 (2017)

• Study of hemoglobin response to mid-ultraviolet (UVB) radiation using
micro-Raman spectroscopy
• Authors: Y. Y. Huang; N. Li; S. N. Zhou; Z. T. Huang; Z. F. Zhuang
Abstract: Abstract Confocal micro-Raman spectroscopy is employed to monitor the damage to haemoglobin from mid-ultraviolet (UVB) radiation. We obtained the Raman spectra of an erythrocyte, which indicated that a peroxidation reaction occurs after UVB radiation. Further, the surface enhanced Raman scattering (SERS) spectra of isolated haemoglobin show that the intensities of the 1375 and 1399 cm−1 bands, which are markers of haem aggregation, obviously increase with prolonged UVB irradiation. This increase reveals that haem aggregation occurs in the peroxidation of erythrocytes. The UV–Vis spectra of isolated haemoglobin indicate that the Soret band, which is indicative of excitonic interactions in the aggregated haems, has a redshift (~12 nm) after 30 min of UVB irradiation of erythrocytes. It can be deduced that an excitonic interaction occurs in the aggregated haems, which is caused by haemoglobin denaturation following UVB irradiation. In addition, the changes of the Raman marker bands during aggregation primarily originate from excitonic interactions. Throughout the process, a higher UVB radiation dose causes greater damage to haemoglobin.
PubDate: 2017-08-24
DOI: 10.1007/s00340-017-6800-1
Issue No: Vol. 123, No. 9 (2017)

• Optical frequency locked loop for long-term stabilization of broad-line
DFB laser frequency difference
• Authors: Michał Lipka; Michał Parniak; Wojciech Wasilewski
Abstract: Abstract We present an experimental realization of the optical frequency locked loop applied to long-term frequency difference stabilization of broad-line DFB lasers along with a new independent method to characterize relative phase fluctuations of two lasers. The presented design is based on a fast photodiode matched with an integrated phase-frequency detector chip. The locking setup is digitally tunable in real time, insensitive to environmental perturbations and compatible with commercially available laser current control modules. We present a simple model and a quick method to optimize the loop for a given hardware relying exclusively on simple measurements in time domain. Step response of the system as well as phase characteristics closely agree with the theoretical model. Finally, frequency stabilization for offsets within 4–15 GHz working range achieving <0.1 Hz long-term stability of the beat note frequency for 500 s averaging time period is demonstrated. For these measurements we employ an I/Q mixer that allows us to precisely and independently measure the full phase trace of the beat note signal.
PubDate: 2017-08-24
DOI: 10.1007/s00340-017-6808-6
Issue No: Vol. 123, No. 9 (2017)

• Effects of whispering gallery mode in microsphere super-resolution imaging
• Authors: Song Zhou; Yongbo Deng; Wenchao Zhou; Muxin Yu; H. P. Urbach; Yihui Wu
Abstract: Abstract Whispering Gallery modes have been presented in microscopic glass spheres or toruses with many applications. In this paper, the possible approaches to enhance the imaging resolution by Whispering Gallery modes are discussed, including evanescent waves coupling, transformed and illustration by Whispering Gallery modes. It shows that the high-order scattering modes play the dominant role in the reconstructed virtual image when the Whispering Gallery modes exist. Furthermore, we find that the high image resolution of electric dipoles can be achieved, when the out-of-phase components exist from the illustration of Whispering Gallery modes. Those results of our simulation could contribute to the knowledge of microsphere-assisted super-resolution imaging and its potential applications.
PubDate: 2017-08-23
DOI: 10.1007/s00340-017-6815-7
Issue No: Vol. 123, No. 9 (2017)

• Spectral characteristics of multi-line Q-switched CO laser radiation
frequency converted in ZnGeP 2
• Authors: A. A. Ionin; I. O. Kinyaevskiy; Yu. M. Klimachev; D. S. Kryuchkov; A. M. Sagitova; E. S. Sunchugasheva
Abstract: Abstract Lasing on different spectral lines belonging to a giant pulse of multi-line Q-switched CO laser was experimentally studied. The Q-switched CO laser emitted a giant microsecond pulse that consisted of about one hundred subpulses corresponding to different rotational–vibrational transitions. Amplitude, time delay and duration were measured for such a laser subpulse, and processes affecting formation of the CO laser giant pulse spectrum were analyzed. These data were taken into account to correctly estimate peak power and the number of spectral lines of radiation formed under sum frequency conversion of the CO laser radiation in nonlinear ZnGeP2 crystal.
PubDate: 2017-08-23
DOI: 10.1007/s00340-017-6812-x
Issue No: Vol. 123, No. 9 (2017)

wavelengths of double-coated fiber Bragg grating with different
coating-layer thickness
• Authors: Faramarz E. Seraji; Golnoush Toutian
Abstract: Abstract Fiber Bragg grating (FBG) of different configurations used as sensing devices are vulnerable to environmental factors, such as static pressures and thermal loading, which cause their characteristic Bragg reflecting wavelengths to up/down-shift. In this paper, by considering double-coated FBG with different primary and secondary coating materials, the effects of thermal loading and hydrostatic pressure on FBG with different coating-layer thicknesses are analyzed to find design criteria for controlling the Bragg wavelength shift. The obtained results of the analysis may be employed as criteria to design pressure and temperature sensors when using double-coated FBGs.
PubDate: 2017-09-19
DOI: 10.1007/s00340-017-6829-1
Issue No: Vol. 123, No. 10 (2017)

• Interband and free charge carrier absorption in silicon at 800 nm:
experiments and model calculations
• Authors: W. I. Ndebeka; P. H. Neethling; E. G. Rohwer; C. M. Steenkamp; J. Bergmann; H. Stafast
Abstract: Abstract The average transmitted power of a Ti:sapphire femtosecond (fs) laser beam through thin, oxidized silicon (Si) membranes in the 10–30  $$\, \upmu \text{m}$$ thickness range at $$45{^\circ }$$ external angle of incidence at first increases with the incident average laser power and then decreases considerably. This stationary state behavior is quantitatively reproduced by a recently derived model using an effective absorption coefficient $$\alpha _{\text {eff}} = \alpha _{1} + \alpha _{\text {FCA}}$$ , adding the coefficients of two independent linear absorption processes, $$\alpha _{1}$$ of the indirect interband transition and $$\alpha _{\text {FCA}}$$ of free charge carrier absorption (FCA). The relations between the empirical parameter $$\alpha _{\text {FCA}}$$ and the model parameters $$n_{\text {eh}}$$ (density of free charge carriers) and $$\sigma _{\text {eh}}$$ (absorption cross section of free charge carriers) are found to depend on the Si membrane thickness and are briefly discussed. Using different sample thicknesses, experimental evidence has been found for a nonlinear intensity dependence of $$\alpha _{\text {FCA}}$$ ∼ $$I_{0}^{n}$$ , where $$1\le n \le 3$$ shows systematic variation. The FCA model in combination with its empirical fit parameters allowed to fully calculate the transmission behavior of the Si membranes within the investigated sample thickness and laser power regimes.
PubDate: 2017-09-18
DOI: 10.1007/s00340-017-6824-6
Issue No: Vol. 123, No. 10 (2017)

• Nanostructured plasmas for enhanced gamma emission at relativistic laser
interaction with solids
• Authors: K. A. Ivanov; D. A. Gozhev; S. P. Rodichkina; S. V. Makarov; S. S. Makarov; M. A. Dubatkov; S. A. Pikuz; D. E. Presnov; A. A. Paskhalov; N. V. Eremin; A. V. Brantov; V. Yu. Bychenkov; R. V. Volkov; V. Yu. Timoshenko; S. I. Kudryashov; A. B. Savel’ev
Abstract: Abstract The hot plasma formed onto the surface of nanostructured targets by a relativistically intense (up to 4 × 1018 W/cm2), high contrast femtosecond laser radiation is studied. The nanoscale structures (pores, spheres, grass) were produced via laser ablation or chemical etching of bulk silicon and molybdenum. We report one of the first experimentally observed manifold enhancements of gamma yield at the background of hot electron energy growth from 200 to >600 keV, compared to the case of initially flat substrate in the relativistic regime of interaction. The efficiency of hot particle production is significantly affected by the shape of the structures. Experimental results are supported by 2D3V Particle-In-Cell simulations of laser–plasma interaction. It is shown that a laser-based plasma source, formed onto the surface of a solid target may be utilized for phase contrast X-ray imaging in a wide energy range of photons.
PubDate: 2017-09-15
DOI: 10.1007/s00340-017-6826-4
Issue No: Vol. 123, No. 10 (2017)

• Field laser applications in industry and research
• Authors: E. Kerstel; F. D’Amato; A. Fried
PubDate: 2017-09-14
DOI: 10.1007/s00340-017-6827-3
Issue No: Vol. 123, No. 10 (2017)

• Picosecond laser fabrication of nanostructures on ITO film surface
assisted by pre-deposited Au film
• Authors: H. Z. Yang; G. D. Jiang; W. J. Wang; X. S. Mei; A. F. Pan; Z. Y. Zhai
Abstract: Abstract With greater optical penetration depth and lower ablation threshold fluence, it is difficult to directly fabricate large scales of laser-induced periodic surface structures (LIPSSs) on indium–tin–oxide (ITO) films. This study proposed an approach to obtain optimized LIPSSs by sputtering an Au thin film on the ITO film surface. The concept behind the proposal is that the upper layer of the thin Au film can cause surface energy aggregation, inducing the initial ripple structures. The ripples deepened and become clear with lower energy due to optical trapping. The effective mechanism of Au film was analyzed and verified by a series of experiments. Linear sweep, parallel to the laser polarization direction, was performed using a Nd:VAN laser system with 10-ps Q-switched pulse, at a central wavelength of 532 nm, with a repetition rate of 1 kHz. The complete and clear features of the nanostructures, obtained with the periods of approximately 320 nm, were observed on ITO films with proper laser fluence and scanning speed. The depth of ripples was varying in the range of 15–65 nm with clear and coherent ITO films. The preferred efficiency of fabricating nanostructures and the excellent results were obtained at a scanning speed of 2.5 mm/s and a fluence of 0.189 J/cm2. In this way, the ablation and shedding of ITO films was successfully avoided. Thus, the proposed technique can be considered to be a promising method for the laser machining of special nonmetal films.
PubDate: 2017-09-14
DOI: 10.1007/s00340-017-6822-8
Issue No: Vol. 123, No. 10 (2017)

• Broadband high contrast ratio optical diodes based on polarization
conversion
• Abstract: Abstract We propose an alternative method to realize broadband high contrast ratio optical diodes based on polarization conversion between transverse electric (TE) wave and transverse magnetic (TM) wave with two slabs of uniaxial hyperbolic crystal. Taking hexagonal boron nitride as an example of the crystal, our numerical simulation results show that asymmetric transmission can occur in the wavelength range from 6.40 to 7.38 μm for incidence of a TM wave, and the transmissivity contrast ratio can be beyond 1000 in the wavelength range from 6.63 to 7.33 μm. For incidence of a TE wave, the asymmetric transmission with the transmissivity contrast ratio higher than 1000 is found in the wavelength range from 12.33 to 12.88 μm. Given that the structure is novel and simple, it may provide a promising prototype for designing high performance integrated photonic devices, such as optical logic gate and optical memory.
PubDate: 2017-09-08
DOI: 10.1007/s00340-017-6821-9

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