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Vortex lattices with transverse-mode-locking states switching in a large-aperture off-axis-pumped solid-state laser

Yijie Shen, Zhensong Wan, Xing Fu, and Mali Gong

Doc ID: 340490 Received 24 Jul 2018; Accepted 11 Oct 2018; Posted 12 Oct 2018  View: PDF

Abstract: We report the optical vortex lattices (OVL) beams with phase-singularity arrays from a large-aperture diode-pumped Yb:CALGO laser. A distinct transverse-mode-locking (TML) effect is found in the OVL formation via controlling pump aperture and off-axis displacement. Various OVL patterns with vortex arrays can be generated in a TML state. While in a non-TML state, the emission is always a high-order Hermite-Gaussian or Ince-Gaussian mode. Interestingly, a stable TML can be started from a non-TML state by an intentionally induced perturbation. Based on TML principle, a new closed-form expression is theoretically proposed for interpreting both the transverse patterns and the evolution principle of various OVL modes, showing good agreements with the experimental results.

Creating mid-infrared single photons

Richard McCracken, Francesco Graffitti, and Alessandro Fedrizzi

Doc ID: 340177 Received 23 Jul 2018; Accepted 10 Oct 2018; Posted 12 Oct 2018  View: PDF

Abstract: Single-photon creation through parametric downconversion underpins quantum technology for quantum sensing and imaging. Here we numerically study the creation of single photons in the near- and mid-infrared regime from 1.5-12μm in a range of novel nonlinear semiconductor and chalcopyrite materials. We identify phase-matching conditions and single out regimes in which group-velocity matching can be achieved with commercially available pump lasers. Finally, we discuss how mid-infrared single photons can be detected. Using our numerical results, we identify materials and pump lasers for up-conversion detection in conventional wavelength bands. Our study provides a complete recipe for mid-IR single-photon generation and detection, opening up quantum enhancements for mid-IR applications such as bio-medical imaging, communication, and remote sensing.

“Hybridized” amplification of superposition of coherent states with homodyne detection

Changhun Oh and Hyunseok Jeong

Doc ID: 341354 Received 01 Aug 2018; Accepted 08 Oct 2018; Posted 10 Oct 2018  View: PDF

Abstract: We investigate an experimentally feasible scheme for amplification of superpositions of coherent states (SCSs) in light fields. This scheme mixes two input SCSs at a 50:50 beam splitter and performs post-selection by a homodyne detection on one output mode. The key idea is to use two different types of SCSs with opposite parities for input states, which results in an amplified output SCS with a nearly perfect fidelity.

A general solution to wave propagation in media undergoing arbitrary transient or periodic temporal variations of permittivity

Mahdi Chegnizadeh, Khashayar Mehrany, and Mohammad Memarian

Doc ID: 340457 Received 24 Jul 2018; Accepted 08 Oct 2018; Posted 09 Oct 2018  View: PDF

Abstract: A novel and general formulation for wave propagation in time-varying media is presented. Unlike previous reports, our formalism is able to solve propagation in media with arbitrary time-variations of permittivity or permeability, for both transient and steady-state periodic variations. The formulation is approximate yet strikingly accurate in most practical cases. The provided closed form expressions show that the normalized average power after the transition of the permittivity does not depend on the details of the transition while the energy density does. Some important discussions are made about time-periodic media and it is shown that there is an accumulation of energy when the Bragg condition is met. All results are validated through comparison against analytical or numerical solutions.

Ultrafast excitation of conduction-band electrons by high-intensity ultrashort laser pulses in wide-band-gap solids: Vinogradov equation vs Drude model

Olga Sergaeva, Vitaly Gruzdev, Drake Austin, and Enam Chowdhury

Doc ID: 331595 Received 24 May 2018; Accepted 07 Oct 2018; Posted 09 Oct 2018  View: PDF

Abstract: Heating of conduction-band electrons is one of the major processes of energy absorption and transfer in high-intensity ultrafast laser interactions with band-gap solids. It is frequently simulated by assuming high rate of electron-phonon collisions to support intensive one-photon absorption. We utilize the approximation of rare electron-phonon collisions and the non-perturbative Vinogradov equation for the rate of collision-assisted absorption by electrons performing laser-driven oscillations. Band-structure modification by ponderomotive energy of the oscillations is taken into account. The Vinogradov model delivers highly non-equilibrium distribution of the conduction electrons dominated by ponderomotive energy of the oscillations. Presented data suggest substantial reconsideration of the physics of ultrafast free-carrier heating.

Ultrabroadband supercontinuum generation through filamentation in lead fluoride crystal

Yang yuxia, wanjun bi, Xia Li, Meisong Liao, Weiqing Gao, Yasutake Ohishi, Yongzheng Fang, and Yigui Li

Doc ID: 341889 Received 08 Aug 2018; Accepted 05 Oct 2018; Posted 09 Oct 2018  View: PDF

Abstract: We report the filamentation and supercontinuum generation of femtosecond pulse in a piece of bulk lead fluoride (PbF2) crystal with high bandgap and ultra-broadband frequency window covering 5.6 octaves. A broadband supercontinuum spanning 4.7 octaves from 350 to 9000 nm is demonstrated. The filament traces and bright conical visible emission patterns of the supercontinuums are observed. Additionally, simulations are performed to investigate the supercontinuum generation in the PbF2 crystal by using waveguide model which considers the supercontinuum generated in the filamentation as a pulse propagated process in the waveguides writing by filamentation. The findings of this study demonstrated that PbF2 crystal is a very suitable nonlinear medium used for supercontinuum generation by filamentation. This is of significance for the development of ultra-broadband SC sources based on bulk media and high-peak power lasers.

Experimental Evidence of Two-Photon Absorption and its saturation in Malachite Green Oxalate: A Femtosecond Z-scan Study

Anshu Gaur, Hamad Syed, Yendeti Balaji, and Venugopal Rao Soma

Doc ID: 335566 Received 20 Jun 2018; Accepted 05 Oct 2018; Posted 09 Oct 2018  View: PDF

Abstract: Third order nonlinear optical properties of malachite green oxalate (MGO) dye were systematically studied at different input intensities and in a wide range of wavelengths by the Z-scan method using ~150 fs, MHz femtosecond pulses. The sample transmittance results are explained by fitting the data with phenomenological models of linear and multi-photon absorption, and their saturations. Intensity dependent measurement shows the influence of saturation on the absorption process. The data suggests that by tuning the input intensity single or combination of nonlinear phenomena can be achieved in MGO. Wavelength based measurements reveal a strong correlation between linear and nonlinear optical responses. The combinations of two- and three photon absorption and saturation of two-photon absorption occur simultaneously in a wide wavelength range (750-900 nm). Nonlinear absorption cross-sections have been calculated using fitted saturation intensity data. Two- and three-photon absorption coefficients (including an excited state) are determined as the excitation mechanisms of nonlinear absorption in MGO.

Scheme for enhancing quadripartite entangled opticalmodes from an opto-mechanical system

Jing Zhang, Xiaoyu Liu, Rongguo Yang, and Tiancai Zhang

Doc ID: 328994 Received 23 Apr 2018; Accepted 03 Oct 2018; Posted 04 Oct 2018  View: PDF

Abstract: Multipartite entanglement is a key resource for quantum information processing and quantum communication.We show that the robust entanglement among four filtered output optical modes can be achievedwhen there is a nonlinear crystal inside an opto-mechanical cavity. The optical parametric amplifier (OPA) gives rise to single-mode squeezing of the cavity modes, therefore the entanglement among four output optical modes can be enhanced remarkably. Furthermore, the degree of quadripartite entanglement is influenced by the nonlinear gain of OPA and the bandwidth of filters. Large entanglement can be obtained by optimizing the filter functions, which is important for utilizing the entangled light beams more efficiently in real experiments. And such kind of multipartite entanglement will be useful and valuable in the area of quantum communication networks.

Correlated electron beam microbunching andshot-noise characterization with near and far fieldoptical transition radiation

Ariel Nause, Reuven Ianconescu, and Avraham Gover

Doc ID: 341655 Received 06 Aug 2018; Accepted 03 Oct 2018; Posted 04 Oct 2018  View: PDF

Abstract: In this work we demonstrate how to analyze the dynamics of the correlated longitudinal current noiseabove and below the Poissonian shot-noise level in an e-beam, by calculating the emitted TransitionRadiation (OTR) using a complex vector field formulation which is exact in the near and far field. We simulatea non zero emittance electron beam, uncorrelated in the transverse cross section, but with differenttypes of longitudinal correlations, resulting in Coherent Optical Transition Radiation (COTR). We showhow this method is applied on the opposite case (suppression), by tracking simulated beam particles thatcorrelate due to quarter plasma oscillation during drift, and show how the OTR tracks the dynamics ofthe electron beam noise level.

Unveiling of control on polarization of supercontinuum spectra based on ultrafast birefringence induced by filamentation

Hui-Tian Wang, Ping-Ping Li, Mengqiang Cai, Jia-Qi Lv, Dan Wang, Gui-Geng Liu, Chenghou Tu, and Yongnan Li

Doc ID: 340025 Received 17 Jul 2018; Accepted 02 Oct 2018; Posted 03 Oct 2018  View: PDF

Abstract: An intensity pump femtosecond (fs) pulse incident into a transparent medium will produce the filamentation and accompany the supercontinuum (SC) spectrum generation. The polarization of the SC spectrum is always parallel to that of the pump pulse. How to control the polarization of the SC spectrum is a very interesting and crucial issue, due to its great potential applications such as in remote-sensing and time-resolved spectroscopy. Here we present a method to control the polarization of the SC spectrum generated in an optical isotropic medium, based on the nonlinear interaction between the two pump pulses with different linear polarizations. During the fs pulse filamentation, the optical Kerr effect induces the ultrafast birefringence in the optical isotropic medium, which leads to different refractive indices in the two orthogonal directions parallel and perpendicular to the incident polarization, hence the resulting relative phase difference changes the polarizations of the pump pulses. The polarization states of both the pump pulses and the SC spectra can be achieved by changing the angle between the polarization directions of two pulses. We unveil the mechanism of the polarization changes of the pump pulses and the SC spectra.

Mid-infrared optical characterization of InGaAsP

Alice Bernard, Marco Ravaro, Iännis Roland, Jean-Michel Gerard, Michel Krakowski, Olivier Parillaud, Bruno Gérard, Ivan Favero, and Giuseppe Leo

Doc ID: 337678 Received 02 Jul 2018; Accepted 01 Oct 2018; Posted 02 Oct 2018  View: PDF

Abstract: We present a measurement of the refractive index of In(1-x)Ga(x)As(y)P(1-y) lattice-matched to InP outside of the range available in literature. We have accurately determined the refractive index of In(1-x)Ga(x)As(y)P(1-y) lattice-matched to InP as a function of wavelength (λ = 1.55, 2.12 and 3 µm) and arsenic molar fraction (y = 0.55, 0.7 and 0.72). Data is interpolated with a theoretical model and compared to literature whenever possible. Agreement with currently available data is good. Uncertainties are estimated, the largest one being related to the samples composition. We also measure propagation losses dominated by scattering (0.15 to 1.2 cm-1) in ridge waveguides, for the same range of compositions at wavelengths 1.55 µm and 2.12 µm.

Magneto-optical control of Imbert-Fedorov shifts of a light beam reflected from interfaced monolayer graphene

luo chang-you, zhiteng wang, Xiaoyu Dai, and Yuanjiang Xiang

Doc ID: 335329 Received 20 Jun 2018; Accepted 30 Sep 2018; Posted 09 Oct 2018  View: PDF

Abstract: We investigate the Imbert-Fedorov (IF) shifts of a reflected light beam from the dielectric interface containing a planar anisotropic monolayer graphene sheet which subject to an external perpendicular magnetic field. We calculate and discuss the dependence of the IF shifts on the intensity of the magnetic field, the incidence angle of the beam and the central frequency of the beam. It is shown that IF shifts can be controlled by modifying the intensity of the magnetic field and the incidence angle without changing material and the structure of the dielectric interface. Moreover, there exists an optimum nonzero control magnetic field under which the IF shift can reach maximum value.

Single-shot ultrafast imaging via spatiotemporal division of femtosecond laser pulses

Ki-Yong Kim, Sarang Yeola, and Donghoon Kuk

Doc ID: 340477 Received 23 Jul 2018; Accepted 29 Sep 2018; Posted 02 Oct 2018  View: PDF

Abstract: We have developed a single-shot imaging technique that can capture ultrafast events occurring on femtosecond to picosecond time scales. The technique is based on an optical pump-probe method, in which multiple time-delayed femtosecond pulses simultaneously probe a pump-excited sample. Here we use two sets of 2-by-2 mirror arrays for spatial/temporal division and routing of multiple probe pulses. This single-shot scheme is successfully applied to capture femtosecond ionization fronts propagating at the speed of light in air, as well as laser-induced ablation of solid targets.

Electromagnetically induced transparency ina spin-orbit coupled finite temperature cold atomic ensemble

Z Hu, Jin-Ming Liu, Chengpu Liu, and Yu-zhu Wang

Doc ID: 334770 Received 14 Jun 2018; Accepted 29 Sep 2018; Posted 02 Oct 2018  View: PDF

Abstract: We investigated the electromagnetically induced transparency in spin-orbit coupled finite temperature cold quantum gases. We showed that spin-orbit coupling can induce additional frequency shift in the absorbed spectral line. This effect can be observed nondestructively in the spectroscopy of the electromagnetically induced transparency and as a alternative method it can be used to detect and measure the spin-orbit coupling sensitively. The spin-orbit coupling can also be used as a switch to control laser light propagation in this medium.

Flexible Design of Multifocal Metalenses Based on Autofocused Airy Beams

Mahdieh Hashemi, mohammad mahdi shanei, and Carlos Zapata-Rodriguez

Doc ID: 340222 Received 19 Jul 2018; Accepted 29 Sep 2018; Posted 03 Oct 2018  View: PDF

Abstract: Extreme miniaturization of on-demand optical devices such as ultrathin lenses is currently on permanent progress based on novel materials and nanotechnologies. Flexibility and tunability in engineering layouts enable efficient integration of complex photonic modules. In this respect, here we designed an Autofocused Airy (AFA)-based metalens which operates, depending on the molded phase profile, as a multifocal focusing lens which up to our knowledge has not been reported before. To do this, we call the attention to the fact that the two conjugate focal points of an AFA beam can be brought into the real space by applying a proper convex lens phase profile. Considering full control of the phase and amplitude of the incident light with dielectric C-shaped metaatoms, we conceived that both generations of the AFA beam and its focusing with a convex lens could be carried out by a compact wavelength-scale metasurface. In addition, hybrid AFA focusing and phase-only lensing are demonstrated as a versatile method to be implemented in designing multifocal setups.

Anti-Stokes Raman gain enabled by modulation instability in mid IR waveguides

alfredo sanchez, Pablo Fierens, Santiago Hernandez, Diego Grosz, Juan Bonetti, and Gilberto Brambilla

Doc ID: 341412 Received 02 Aug 2018; Accepted 27 Sep 2018; Posted 27 Sep 2018  View: PDF

Abstract: Under particular conditions, modulation instability in mid-IR waveguides is shown to give rise to the usual double-sideband spectrum, but with Raman-shaped sidelobes. This results from the energy transfer of a CW laser simultaneously to both Stokes and anti-Stokes bands in pseudo-parametric fashion. As such, the anti-Stokes gain matches completely the Stokes profile over the entire gain bandwidth. This remarkable behavior, not expected from an unexcited medium, is shown not to follow from a conventional four-wave mixing interaction between the pump and the Stokes band.We believe this observation to be of relevance in the area of Raman-based sensors which, in several instances, rely on monitoring small power variations of the anti-Stokes spectral component.

Highly amplitude sensitive photonic crystal fiber based plasmonic sensor

Rifat Ahmmed Aoni, Firoz Haider, Rajib Ahmed, and Andrey Miroshnichenko

Doc ID: 334323 Received 04 Jun 2018; Accepted 26 Sep 2018; Posted 27 Sep 2018  View: PDF

Abstract: Simple structure, quick response and highly sensitive miniaturized sensors are highly desirable for the broad range of sensing applications. In this work, we numerically investigated a highly sensitive photonic crystal fiber (PCF) based plasmonic sensor for the refractive index sensing. We consider gold as a plasmonic material, which is used outside the fiber structure to exhibit the plasmonic phenomena and help to detect surrounding medium refractive index. The proposed PCF is designed to enable the evanescent field to interact with an external sensing medium leading to a highly sensitive response. The sensor performance has been investigated by wavelength and amplitude interrogation methods. The proposed sensor exhibits the maximum amplitude sensitivity of 2,843 RIU-1 with the sensor resolution of 3.5×10-6 RIU, which is highest among the reported PCF SPR sensors, to the best of our knowledge. It also shows the wavelength sensitivity of 18,000 nm/RIU and the sensor resolution of 5.6×10-6 RIU. The figure of merit of the proposed sensor is about 400. The sensor response also allows to detect the refractive index variation in the range of 1.33 to 1.41. Such promising results and broad sensing range ensure that the proposed sensor will be a suitable candidate for biological analytes, biochemical and organic chemical detections.

Laser-induced rotation of spheroidal metal nanoparticle in a medium.

Nicolas I. Grigorchuk

Doc ID: 340065 Received 23 Jul 2018; Accepted 26 Sep 2018; Posted 27 Sep 2018  View: PDF

Abstract: A theory for the generation in a spheroidal metallic nanoparticle of a mechanical torque under the action of an ultrashort laser pulse is developed. We proposed the new mechanism for generation of rotation force associated with nanoparticle polarization in the frequency region close to the surface plasmon resonances. It is considered that the polarization becomes a tensor quantity for the nanoparticle sizes smaller than the electron average free path in it. The expressions for the components of the polarization tensor and for the torque of a spheroidal nanoparticle are obtained.

E-band fiber laser performance and power analysis with longitudinally averaged population modeling

Leily Kiani, Raymond Beach, Jay Dawson, Paul Pax, Graham Allen, Derrek Drachenberg, victor khitrov, nick schenkel, Robert Crist, Matthew Cook, and Mike Messerly

Doc ID: 337589 Received 03 Jul 2018; Accepted 25 Sep 2018; Posted 26 Sep 2018  View: PDF

Abstract: To help facilitate the modeling of new fiber laser systems, such as those with complex functional microstructures, we report on a simplified modeling methodology that can accommodate the parasitic kinetic effects often present in such systems. The essence of our approach is to integrate over the length of the gain medium at the outset, thereby forfeiting longitudinally resolved information about the system but simplifying its energetics analysis. To illustrate the benefits of our new approach over more conventional coupled-rate-equation analyses we apply our model to a Nd3+ doped fiber laser operating on the 4F3/2 - 4I13/2 transition at 1400 nm. The model produces closed form solutions for the various output channels available to the pump power and enables projections of ultimate laser performance to be conveniently generated.

Electrodiffusion of molecules in porous glass under the action of laser excitation

Igor Meshkovskiy and George Miroshnichenko

Doc ID: 338361 Received 10 Jul 2018; Accepted 25 Sep 2018; Posted 27 Sep 2018  View: PDF

Abstract: An original molecular separation method is proposed and investigated in which optical excitation of the molecules to be separated is used. The transition of molecules to an excited state substantially reduces their mobility on the capillary surface. An original model of molecular mobility is presented. It is shown that, due to the intercombination conversion, the excited molecules are amassed in the triplet excited state. An analysis of the mobility of excited molecules shows that molecules in a triplet excited state have six times less mobility than molecules in the ground singlet state.

Effect of losses on multipartite entanglement from cascaded four-wave mixing processes

Tianxiang Wei, Shuchao Lv, and Jietai Jing

Doc ID: 340116 Received 18 Jul 2018; Accepted 23 Sep 2018; Posted 25 Sep 2018  View: PDF

Abstract: Multipartite entanglement is an important resource in quantum information. For its generation and manipulation, optical losses are inevitable experimental imperfections that cannot be ignored. In this paper, by using the positivity under partial transposition (PPT) criterion, we theoretically characterize the effect of losses on two multipartite entanglement cases, tripartite entanglement and quadripartite entanglement, which are generated by cascaded four-wave mixing processes. The characterization of entanglement is made possible by calculating the smallest symplectic eigenvalues of the partially transposed covariance matrix (CM). It is verified that when the power gains are smaller than 5, both the tripartite and quadripartite entanglement can be maintained under the realistic experimental condition (less than 20% losses). In addition, we also study how the losses will affect the entanglement of subsystems in both cases. Ourresults pave the way for the experimental implementation of multipartite entanglement in cascaded four-wave mixing processes.

Supercontinuum Generation in Heavy-Metal Oxide Glass Based Suspended-Core Photonic Crystal Fibers: Erratum

Thibaut Sylvestre, AMAR GHOSH, John Dudley, Mariusz Klimczak, and Ryszard Buczynski

Doc ID: 345794 Received 12 Sep 2018; Accepted 14 Sep 2018; Posted 24 Sep 2018  View: PDF

Abstract: This erratum reports a correction to the abstract of article J. Opt. Soc. Am. B 35,  11 (2018). In Ref. [1], it is written “high nonlinear refractive index up to 4.3·10^19 m^2∕W” instead of 4.3·10^-19 m^2∕W, as wrote in the main text on page 1, 2 and 4. A negative sign is missing in the exponent. The nonlinear index is of course 4.3·10^-19 m^2∕W.[1]A. N. Ghosh, M. Klimczak, R. Buczynski, J. M. Dudley, and T. Sylvestre, "Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers," J. Opt. Soc. Am. B 35, 11- 16 (2018).

Theoretical investigation of the capture effect inIMDD-based microwave photonic mixers

S.Esmail Hosseini and M. Mahdi Keshavarz

Doc ID: 332276 Received 21 May 2018; Accepted 04 Sep 2018; Posted 04 Sep 2018  View: PDF

Abstract: We study the large-signal behavior of microwave photonic (MWP) mixers to investigate the small-signal suppression phenomenon commonly referred to as the capture effect. We introduce and theoretically study the capture effect in the context of MWP mixers. Theoretical expressions are derived for calculatingthe capture effect in three basicMWPmixer types based on intensity-modulation direct-detection (IMDD). We show that the capture effect is not only a function of the power ratio between the input radio-frequency (RF) signals to the MWP mixers, but also depends on the absolute value of their powers. We extendthe study to different unequal-power frequency components of a signal, and as a practical example, we investigate the capture effect when a narrowband FM signal is applied to the RF input of an IMDD-based MWP mixer, theoretically demonstrating considerations and limitations in using MWP mixers.

Wavelength beam combining by spectrally selective polarization transformation

Matvey Pochechuev, Anastasia Suvorina, Pavel Shcheglov, Sergei Nikitin, and Aleksei Zheltikov

Doc ID: 335768 Received 21 Jun 2018; Accepted 04 Sep 2018; Posted 04 Sep 2018  View: PDF

Abstract: Efficient wavelength beam combining is demonstrated using spectrally selective polarization transformation in carefully designed stacks of birefringent plates combined with polarization-selective beam splitters. This beam-combining scheme is shown to enable a high-throughput power and intensity scaling of blue-diode-laser arrays. The wavelengths of individual diode lasers in the laser array are shifted with respect to each other by a few nanometers, by fine temperature adjustment, for the highest overall output radiance, limited by étendue conservation.

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