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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]
• Accuracy of non-resonant laser-induced thermal acoustics (LITA) in a
convergent–divergent nozzle flow
• Authors: J. Richter; J. Mayer; B. Weigand
Abstract: Abstract Non-resonant laser-induced thermal acoustics (LITA) was applied to measure Mach number, temperature and turbulence level along the centerline of a transonic nozzle flow. The accuracy of the measurement results was systematically studied regarding misalignment of the interrogation beam and frequency analysis of the LITA signals. 2D steady-state Reynolds-averaged Navier–Stokes (RANS) simulations were performed for reference. The simulations were conducted using ANSYS CFX 18 employing the shear-stress transport turbulence model. Post-processing of the LITA signals is performed by applying a discrete Fourier transformation (DFT) to determine the beat frequencies. It is shown that the systematical error of the DFT, which depends on the number of oscillations, signal chirp, and damping rate, is less than $$1.5\%$$ for our experiments resulting in an average error of $$1.9\%$$ for Mach number. Further, the maximum calibration error is investigated for a worst-case scenario involving maximum in situ readjustment of the interrogation beam within the limits of constructive interference. It is shown that the signal intensity becomes zero if the interrogation angle is altered by $$2\%$$ . This, together with the accuracy of frequency analysis, results in an error of about $$5.4\%$$ for temperature throughout the nozzle. Comparison with numerical results shows good agreement within the error bars.
PubDate: 2018-01-10
DOI: 10.1007/s00340-017-6885-6
Issue No: Vol. 124, No. 2 (2018)

• Accelerated endurance test of single-mode vertical-cavity surface-emitting
lasers under vacuum used for a scalar space magnetometer
• Authors: M. Ellmeier; C. Hagen; J. Piris; R. Lammegger; I. Jernej; M. Woschank; W. Magnes; E. Murphy; A. Pollinger; C. Erd; W. Baumjohann; L. Windholz
Abstract: Abstract We performed an endurance test with single-mode vertical-cavity surface-emitting lasers (VCSEL) under vacuum condition and increased operational parameters (laser current and laser temperature) to accelerate the aging of the lasers. During the endurance test the emitted polarization-dependent and polarization-independent optical light power from the lasers was detected. Additionally, electro-optical characterisations including measurements of the combination of laser current and laser temperature to excite the 87Rb D1 transition (λ = 795 nm), the current and temperature tuning coefficients, laser line width, threshold current and the polarization ellipse were performed for the aged lasers. The test was started with a number of 12 VCSELs consisting of 4 lasers each from 3 different suppliers. The aging behaviour of VCSELs was investigated with respect to the development of a new optical magnetometer prototype for space missions with a mission duration of up to 17 years. Only a limited change of the electro-optical parameters can be tolerated by the instrument design over the mission duration. The endurance test and the electro-optical characterizations revealed clear differences in the aging behaviour of the three suppliers. Lasers from one supplier showed that they can be operated for more than 17 years under vacuum conditions without major degradation of their operational parameters.
PubDate: 2018-01-06
DOI: 10.1007/s00340-017-6889-2
Issue No: Vol. 124, No. 2 (2018)

• Nanosecond nonlinear optical and optical limiting properties of hollow
gold nanocages
• Authors: Chan Zheng; Jiaxin Huang; Li Lei; Wenzhe Chen; Haiyan Wang; Wei Li
Abstract: Abstract Gold nanocages (NCs) were prepared using the galvanic replacement reaction. Transmission electron microscopy images confirmed the porous morphology and completely hollow interior of the gold NCs. The nanosecond nonlinear optical and optical limiting (OL) properties of the NCs were characterized using the open-aperture Z-scan technique with 8-ns laser pulses at 532 nm. The gold NCs exhibited intensity-dependent transformation from saturable absorption to reverse-saturable absorption. The nonlinear absorption coefficient and saturable energy of the NCs were 5 × 10− 12 m/W and 2.5 × 1010 W/m2, respectively. Meanwhile, the gold NCs were found to display strong OL properties towards nanosecond laser pulses. The OL threshold of the gold NCs was lower than that of solid gold nanoparticles and comparable with that of a carbon nanotube suspension. Input fluence and angle-dependent scattering measurements indicated that nonlinear scattering plays an important role in the OL behavior of the gold nanostructures at high laser excitation. The improved OL response in gold NCs was discussed from the viewpoint of structural characteristic. The ultrathin and highly porous walls of the gold NCs can effectively transfer the photon-induced heat to the surrounding solvent, resulting in enhanced OL properties compared with those of solid gold nanoparticles. The intensity-dependent transformation from saturable absorption to reverse-saturable absorption and excellent OL response indicate that the smart gold NCs with ultrathin and highly porous walls can be considered as potential candidate in pulse shaping, passive mode locking, and eye protection against powerful lasers.
PubDate: 2017-12-27
DOI: 10.1007/s00340-017-6888-3
Issue No: Vol. 124, No. 1 (2017)

• High-energy and ultra-wideband tunable terahertz source with DAST crystal
via difference frequency generation
• Authors: Yixin He; Yuye Wang; Degang Xu; Meitong Nie; Chao Yan; Longhuang Tang; Jia Shi; Jiachen Feng; Dexian Yan; Hongxiang Liu; Bing Teng; Hua Feng; Jianquan Yao
Abstract: Abstract We have demonstrated a high-energy and broadly tunable monochromatic terahertz (THz) source based on difference frequency generation (DFG) in DAST crystal. A high-energy dual-wavelength optical parametric oscillator with two KTP crystals was constructed as a light source for DFG, where the effect of blue light was first observed accompanying with tunable dual-wavelength pump light due to different nonlinear processes. The THz frequency was tuned randomly in the range of 0.3–19.6 THz. The highest energy of 870 nJ/pulse was obtained at 18.9 THz under the intense pump intensity of 247 MW/cm2. The THz energy dips above 3 THz have been analyzed and mainly attributed to the resonance absorption induced by lattice vibration in DAST crystal. The dependence of THz output on the input energy was studied experimentally, and THz output saturation was observed. Furthermore, tests of transmission spectroscopy of four typical samples were demonstrated with this ultra-wideband THz source.
PubDate: 2017-12-26
DOI: 10.1007/s00340-017-6887-4
Issue No: Vol. 124, No. 1 (2017)

• Ultra-sensitive probe of spectral line structure and detection of isotopic
oxygen
• Authors: Richard M. Garner; A. N. Dharamsi; M. Amir Khan
Abstract: Abstract We discuss a new method of investigating and obtaining quantitative behavior of higher harmonic (> 2f) wavelength modulation spectroscopy (WMS) based on the signal structure. It is shown that the spectral structure of higher harmonic WMS signals, quantified by the number of zero crossings and turnings points, can have increased sensitivity to ambient conditions or line-broadening effects from changes in temperature, pressure, or optical depth. The structure of WMS signals, characterized by combinations of signal magnitude and spectral locations of turning points and zero crossings, provides a unique scale that quantifies lineshape parameters and, thus, useful in optimization of measurements obtained from multi-harmonic WMS signals. We demonstrate this by detecting weaker rotational–vibrational transitions of isotopic atmospheric oxygen (16O18O) in the near-infrared region where higher harmonic WMS signals are more sensitive contrary to their signal-to-noise ratio considerations. The proposed approach based on spectral structure provides the ability to investigate and quantify signals not only at linecenter but also in the wing region of the absorption profile. This formulation is particularly useful in tunable diode laser spectroscopy and ultra-precision laser-based sensors where absorption signal profile carries information of quantities of interest, e.g., concentration, velocity, or gas collision dynamics, etc.
PubDate: 2017-12-26
DOI: 10.1007/s00340-017-6882-9
Issue No: Vol. 124, No. 1 (2017)

• Isotope-selective ionization utilizing field-free alignment of
isotopologues using a switched nanosecond laser pulse
• Authors: Hiroshi Akagi; Takayuki Kumada; Tomohito Otobe; Ryuji Itakura; Hirokazu Hasegawa; Yasuhiro Ohshima
Abstract: Abstract We propose and numerically simulate a method of laser isotope separation based on field-free alignment of isotopologues, utilizing an intense “switched” nanosecond (ns) laser field which is slowly turned on and rapidly turned off at the peak with the falling time of 200 fs. The femtosecond (fs) laser-induced alignment of isotopologues including heavy isotopes is severely disturbed by ionization because of their small ionization potential. Our simulations for I79Br and I81Br isotopologues demonstrate that the switched ns laser field can make isotopologues well-aligned with the reduced ionization probability at the laser intensity [I 0 = 2 TW/cm2 (= 2 × 1012 W/cm2)] which is an order-of-magnitude lower than a typical intensity (I 0 = 20 TW/cm2) for field-free alignment induced by a fs laser field. In our simulations, I i Br isotopologues (i = 79 or 81) aligned with the switched ns laser field are selectively ionized by an intense fs laser pulse at an appropriate time delay from the alignment pulse.
PubDate: 2017-12-22
DOI: 10.1007/s00340-017-6884-7
Issue No: Vol. 124, No. 1 (2017)

• Multi-mode dynamics of optical oscillators based on intracavity nonlinear
frequency down-conversion
• Authors: Yuri A. Morozov
Abstract: Abstract The transient power characteristics of two optical oscillators—a difference frequency generator (ICDFG) and a singly resonant optical parametric oscillator (ICSRO)—based on intracavity nonlinear optical frequency conversion, are described. The simulation has been performed via the rate-equation mathematical model, which features a multi-mode behavior of all optical fields. The reason for unattainability of single-mode emission in these devices without an additional frequency-selective element (e.g., a Fabry–Perot etalon) is clarified. It is shown that the dynamics of a short-wavelength emission (pump) results mainly from the nonlinear optical interaction, while that of the longer-wavelength optical fields (signal and idler) depends on selectivity of the etalon. With the suitable etalons inserted in their cavities, both devices are shown to operate dynamically single-mode under conventional experimental conditions. The nonlinear interaction makes the pump emission collapse to the single-mode operation very fast (it takes no more than a few tens of the photon lifetimes). To overcome the threshold of parametric generation, the intracavity pump power in the ICSRO has to exceed $$\sim 100$$ W, while the ICDFG is essentially a “thresholdless” device.
PubDate: 2017-12-21
DOI: 10.1007/s00340-017-6881-x
Issue No: Vol. 124, No. 1 (2017)

• Generation of pure longitudinal magnetization needle with tunable
longitudinal depth by focusing azimuthally polarized beams
• Authors: Jian Fu; Xiaochang Yu; Ying Wang; Peifeng Chen
Abstract: Abstract Based on the inverse Faraday effect, a pure longitudinal magnetization with a tunable longitudinal depth and a high corresponding aspect ratio can be generated by tightly focusing a narrow annulus of azimuthally polarized beam on optomagnetic materials. Theoretical calculation demonstrates that the induced magnetization has the same longitudinal depth as the beam needle, but with different distributions. The magnetization needle can be tunable by changing the value of the angular thickness ∆θ, and a long longitudinal depth (91.4λ) can be achieved.
PubDate: 2017-12-21
DOI: 10.1007/s00340-017-6886-5
Issue No: Vol. 124, No. 1 (2017)

• A discretely tunable dual-wavelength multi-watt Yb:CALGO laser
• Authors: Sujith Manjooran; Pavel Loiko; Arkady Major
Abstract: Abstract A discretely tunable dual-wavelength diode-pumped Yb:CALGO laser using a single birefringent filter (BRF) plate which covered a wavelength range of approximately 1020–1070 nm was demonstrated. A detailed study was conducted for BRF plates with thickness of 0.5, 2, 4 and 6 mm using different output couplers. This simple design was capable of delivering multi-watt dual-wavelength output power and the frequency offset discretely varied from approximately 1.3 to 12.5 THz. The maximum dual-wavelength output power was 4.1 W using a 6-mm-thick BRF plate with 5% output coupler.
PubDate: 2017-12-21
DOI: 10.1007/s00340-017-6873-x
Issue No: Vol. 124, No. 1 (2017)

• Two-dimensional electroacoustic waves in silicene
• Authors: Alexander V. Zhukov; Roland Bouffanais; Natalia N. Konobeeva; Mikhail B. Belonenko
Abstract: Abstract In this letter, we investigate the propagation of two-dimensional electromagnetic waves in a piezoelectric medium built upon silicene. Ultrashort optical pulses of Gaussian form are considered to probe this medium. On the basis of Maxwell’s equations supplemented with the wave equation for the medium’s displacement vector, we obtain the effective governing equation for the vector potential associated with the electromagnetic field, as well as the component of the displacement vector. The dependence of the pulse shape on the bandgap in silicene and the piezoelectric coefficient of the medium was analyzed, thereby revealing a nontrivial triadic interplay between the characteristics of the pulse dynamics, the electronic properties of silicene, and the electrically induced mechanical vibrations of the medium. In particular, we uncovered the possibility for an amplification of the pulse amplitude through the tuning of the piezoelectric coefficient. This property could potentially offer promising prospects for the development of amplification devices for the optoelectronics industry.
PubDate: 2017-12-20
DOI: 10.1007/s00340-017-6879-4
Issue No: Vol. 124, No. 1 (2017)

• Tunable, high-repetition-rate, dual-signal-wavelength femtosecond optical
parametric oscillator based on BiB 3 O 6
• Authors: Xianghao Meng; Zhaohua Wang; Wenlong Tian; Shaobo Fang; Zhiyi Wei
Abstract: Abstract We have demonstrated a high-repetition-rate tunable femtosecond dual-signal-wavelength optical parametric oscillator (OPO) based on BiB3O6 (BiBO) crystal, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser. The cavity is simple since no dispersion compensators are used in the cavity. The wavelength range of dual-signal is widely tunable from 710 to 1000 nm. Tuning is accomplished by rotating phase-matching angle of BiBO, and optimizing cavity length and output coupler. Using a 3.75 W pump laser, the maximum average dual-signal output power is 760 mW at 707 and 750 nm, leading to a conversion efficiency of 20.3% not taking into account the idler power. Our experimental results show a non-critical phase-matching configuration pumped by a high peak power laser source. The operation of the dual-signal benefits from the balance of phase matching and group velocity mismatching between the two signals.
PubDate: 2017-12-19
DOI: 10.1007/s00340-017-6877-6
Issue No: Vol. 124, No. 1 (2017)

• Detection of carbon monoxide (CO) in sooting hydrocarbon flames using
femtosecond two-photon laser-induced fluorescence (fs-TPLIF)
• Authors: Yejun Wang; Waruna D. Kulatilaka
Abstract: Abstract Ultrashort-pulse, femtosecond (fs)-duration, two-photon laser-induced fluorescence (fs-TPLIF) measurements of carbon monoxide (CO) are reported in rich, sooting hydrocarbon flames. CO-TPLIF detection using conventional nanosecond or picosecond lasers are often plagued by photochemical interferences, specifically under fuel-rich flames conditions. In the current study, we investigate the commonly used CO two-photon excitation scheme of the B1Σ+ ← X1Σ+ electronic transition, using approximately 100-fs-duration excitation pulses. Fluorescence emission was observed in the Ångström band originating from directly populated B1Σ+ upper state, as well as, in the third positive band from collisionally populated b3Σ+ upper state. The current work was focused on the Ångström band emission. Interference from nascent C2 emissions originating from hot soot particles in the flame could be reduced to a negligible level using a narrower detection gate width. In contrast, avoiding interferences from laser-generated C2 Swan-band emissions required specific narrowband spectral filtering in sooting flame conditions. The observed less than quadratic laser pulse energy dependence of the TPLIF signal suggests the presence of strong three-photon ionization and stimulated emission processes. In a range of CH4/air and C2H4/air premixed flames investigated, the measured CO fluorescence signals agree well with the calculated equilibrium CO number densities. Reduced-interference CO-TPLIF imaging in premixed C2H4/O2/N2 jet flames is also reported.
PubDate: 2017-12-18
DOI: 10.1007/s00340-017-6878-5
Issue No: Vol. 124, No. 1 (2017)

• Q-switched oscillation in thulium-doped fiber lasers using preloaded
dynamic microbending technique
• Authors: H. Sakata; N. Takahashi; Y. Ushiro
Abstract: Abstract We demonstrate Q-switched pulse generation in thulium-doped fiber lasers by introducing piezoelectric-driven microbend with preloaded stress. We employed a pair of corrugated chips each attached on piezoelectric actuators (PAs) to clamp the fiber in a ring laser resonator. The thulium-doped fiber is pumped by a laser diode emitting at 1.63 μm and generates the Q-switched laser pulses at around 1.9 μm by switching off the PAs. The laser pulse performance is improved by optimizing the preload and switch-off period for the PAs. The Q-switched pulses with a peak power of 2.8 W and a pulsewidth of 900 ns are observed for a launched pump power of 161 mW. We expect that the in-fiber Q-switching technique will provide efficient laser systems for environmental sensing and medical applications.
PubDate: 2017-12-13
DOI: 10.1007/s00340-017-6875-8
Issue No: Vol. 124, No. 1 (2017)

• Diode-pumped mid-infrared YVO 4 Raman laser at 2418 nm
• Authors: Ping Cheng; Jiaqun Zhao; Feng Xu; Xiaofeng Zhou; Guodong Wang
Abstract: Abstract A mid-infrared YVO4 Raman laser intracavity-pumped by a diode-pumped actively Q-switched Tm:YAP laser at 1990 nm is demonstrated for the first time. An a-cut 30-mm-long YVO4 crystal is utilized in the Raman laser as a gain medium. With an incident diode pump power of 10.9 W, an average output power of 272 mW at the first Stokes wavelength of 2418 nm is obtained at a pulse repetition rate (PRR) of 1 kHz. The optical conversion efficiency from the diode pump to the first Stokes is about 2.5%. The corresponding pulse width and single pulse energy of the first Stokes are 15 ns and 0.27 mJ, respectively. Compared with the spectrum of the fundamental laser at 1990 nm, the output spectrum of the first Stokes at 2418 nm has a broader linewidth of approximately 10 nm.
PubDate: 2017-12-12
DOI: 10.1007/s00340-017-6876-7
Issue No: Vol. 124, No. 1 (2017)

• Polarization mechanism in a ns laser-induced plasma spectroscopy of Al
alloy
• Authors: Mahboobeh Aghababaei Nejad; Mahmood Soltanolkotabi; Abdollah Eslami Majd
Abstract: Abstract Polarization emission from aluminum alloy by ns laser-induced breakdown spectroscopy (LIBS) is carefully investigated in air using a non-gated CCD camera at integration time of 100 ms. First, the analysis reveals that the small polarization degree is the same for both continuum and discrete line emission spectra which also increases slowly with wavelength growth; second, laser fluence in the range of 347.81–550.10 J/cm2 has no significant changes in plasma polarization; and third, larger polarization in comparison with polarization introduced by preferential reflection of emission from the target surface (Fresnel reflectivity) is observed. The residual fluctuations of the anisotropic recombining plasma and the dynamic polarization of an ion’s core are suggested as the possible main sources for observed polarized radiation in ns-LIBS.
PubDate: 2017-12-12
DOI: 10.1007/s00340-017-6880-y
Issue No: Vol. 124, No. 1 (2017)

• All-fiber high-power monolithic femtosecond laser at 1.59 µm
with 63-fs pulse width
• Authors: M. J. Hekmat; M. Omoomi; A. Gholami; A. Bagheri Yazdabadi; M. Abdollahi; E. Hamidnejad; A. Ebrahimi; H. Normohamadi
Abstract: Abstract In this research, by adopting an alternative novel approach to ultra-short giant pulse generation which basically originated from difficulties with traditional employed methods, an optimized Er/Yb co-doped double-clad fiber amplifier is applied to boost output average power of single-mode output pulses to a high level of 2-W at 1.59-µm central wavelength. Output pulses of approximately 63-fs pulse width at 52-MHz repetition rate are obtained in an all-fiber monolithic laser configuration. The idea of employing parabolic pulse amplification for stretching output pulses together with high-power pulse amplification using Er/Yb co-doped active fibers for compressing and boosting output average power plays crucial role in obtaining desired results. The proposed configuration enjoys massive advantages over previously reported literature which make it well-suited for high-power precision applications such as medical surgery. Detailed dynamics of pulse stretching and compressing in active fibers with different GVD parameters are numerically and experimentally investigated.
PubDate: 2017-12-11
DOI: 10.1007/s00340-017-6874-9
Issue No: Vol. 124, No. 1 (2017)

• Photonic quantum simulator for unbiased phase covariant cloning
• Authors: Laura T. Knoll; Ignacio H. López Grande; Miguel A. Larotonda
Abstract: Abstract We present the results of a linear optics photonic implementation of a quantum circuit that simulates a phase covariant cloner, using two different degrees of freedom of a single photon. We experimentally simulate the action of two mirrored $$1\rightarrow 2$$ cloners, each of them biasing the cloned states into opposite regions of the Bloch sphere. We show that by applying a random sequence of these two cloners, an eavesdropper can mitigate the amount of noise added to the original input state and therefore, prepare clones with no bias, but with the same individual fidelity, masking its presence in a quantum key distribution protocol. Input polarization qubit states are cloned into path qubit states of the same photon, which is identified as a potential eavesdropper in a quantum key distribution protocol. The device has the flexibility to produce mirrored versions that optimally clone states on either the northern or southern hemispheres of the Bloch sphere, as well as to simulate optimal and non-optimal cloning machines by tuning the asymmetry on each of the cloning machines.
PubDate: 2017-11-30
DOI: 10.1007/s00340-017-6871-z
Issue No: Vol. 124, No. 1 (2017)

• Simulated Fizeau ring fringes in transmission through spherical and plane
reflected surfaces
• Authors: W. A. Ramadan; H. H. Wahba
Abstract: Abstract In this paper, we present simulated Fizeau ring fringes. These fringes are constructed due to multiple reflection between highly reflected partially transmitted spherical and plane surfaces. The real paths of rays and consequently their amplitudes and phases have been determined when they reached the image plane. This plane is located at a certain distance above the interferometer. In these calculations, the impact of the image plane position, the radius of the spherical surface and the distance between the two surfaces on the fringe intensity distribution are investigated. A quite interesting result of our calculation is that the number of the interfered rays is varied and could be only two, even for a highly reflected surfaces. Three different estimated visualizations are included to give an overview imagination of the impact of the different parameter variation. These could be helpful for researchers for testing of spherical surfaces using interference-based methods.
PubDate: 2017-11-30
DOI: 10.1007/s00340-017-6872-y
Issue No: Vol. 124, No. 1 (2017)

• An “in-fiber” Whispering-Gallery-Mode bi-sphere resonator, sensitive
to nanometric displacements
• Authors: Kyriaki Kosma; Kay Schuster; Jens Kobelke; Stavros Pissadakis
Abstract: Abstract A double-cavity, Whispering-Gallery-Mode (WGM) resonator, composed of two polystyrene microspheres, is formed inside the capillary of a microstructured optical fiber. The spectra are compared with the corresponding WGM patterns of the isolated microspheres. We collect scattering spectra from the contact area between the two beads, as the spacing between them is varied, and the evolution of the modes with sphere separation is discussed. Potential applications of the presented optical design are also proposed.
PubDate: 2017-11-29
DOI: 10.1007/s00340-017-6866-9
Issue No: Vol. 124, No. 1 (2017)

• Impact of detuning on the performance of semiconductor disk lasers
• Authors: Fan Zhang; Christoph Möller; Martin Koch; Stephan W. Koch; Arash Rahimi-Iman; Wolfgang Stolz
Abstract: Abstract We investigate the impact of the spectral detuning between micro-cavity resonance and material gain on the high-power operation of semiconductor disk lasers exploiting the connection between cavity angle and micro-cavity resonance. Our investigation shows that by altering the cavity-angle-dependent detuning, we can modify such device’s performance in strong correlation with the detuning. A change of the maximum output power by factor of two is observed. The threshold pump powers are even modified by a factor of four. Moreover, the wavelength tunability is investigated, showing that it can be enhanced by the choice of a respective detuning.
PubDate: 2017-11-24
DOI: 10.1007/s00340-017-6860-2
Issue No: Vol. 123, No. 12 (2017)

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