liu.seSearch for publications in DiVA
Change search
Refine search result
1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Arabi, C. Mas
    et al.
    Univ Libre Bruxelles, Belgium.
    Parra-Rivas, P.
    Univ Libre Bruxelles, Belgium; Univ Leuven, Belgium.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Gelens, L.
    Univ Leuven, Belgium.
    Wabnitz, S.
    Sapienza Univ Rome, Italy; CNR INO, Italy; Novosibirsk State Univ, Russia.
    Leo, F.
    Univ Libre Bruxelles, Belgium.
    Localized structures formed through domain wall locking in cavity-enhanced second-harmonic generation2020In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 45, no 20, p. 5856-5859Article in journal (Refereed)
    Abstract [en]

    We analyze the formation of localized structures in cavity-enhanced second-harmonic generation. We focus on the phase-matched limit, and consider that fundamental and generated waves have opposite signs of group velocity dispersion. We show that these states form due to the locking of domain walls connecting two stable homogeneous states of the system, and undergo collapsed snaking. We study the impact of temporal walk-off on the stability and dynamics of these localized states. (C) 2020 Optical Society of America

  • 2.
    Boggio, J. M. Chavez
    et al.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Bodenmueller, D.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Ahmed, S.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Baig, A.
    innoFSPEC Leibniz Inst Astrophys Potsdam AIP, Germany.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Talenti, F.
    Sapienza Univ Rome, Italy.
    Wabnitz, S.
    Sapienza Univ Rome, Italy.
    Modotto, D.
    Univ Brescia, Italy.
    Frequency comb generation in silicon nitride resonators with amplitude modulated pump2021In: LASER RESONATORS, MICRORESONATORS, AND BEAM CONTROL XXIII, SPIE-INT SOC OPTICAL ENGINEERING , 2021, Vol. 11672, article id 1167206Conference paper (Refereed)
    Abstract [en]

    We investigate frequency comb generation in silicon nitride ring resonators by using a pump subject to a weak amplitude modulation. We show that a partial locking is obtained when the external modulation frequency differs from the resonator free-spectral-range by up to hundreds of MHz.

  • 3.
    Boggio, J. M. Chavez
    et al.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Bodenmüller, D.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Ahmed, S.
    InnoFSPEC Leibniz Inst Astrophys Potsdam, Germany.
    Wabnitz, S.
    Sapienza Univ Roma, Italy; Ist Nazl Ottica, Italy.
    Modotto, D.
    Univ Brescia, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Efficient Kerr soliton comb generation in micro-resonator with interferometric back-coupling2022In: Nature Communications, E-ISSN 2041-1723, Vol. 13, no 1, article id 1292Article in journal (Refereed)
    Abstract [en]

    Nonlinear Kerr micro-resonators have enabled fundamental breakthroughs in the understanding of dissipative solitons, as well as in their application to optical frequency comb generation. However, the conversion efficiency of the pump power into a soliton frequency comb typically remains below a few percent. We fabricate and characterize a hybrid Mach-Zehnder ring resonator geometry, consisting of a micro-ring resonator embedded in an additional cavity with twice the optical path length of the ring. The resulting interferometric back coupling enables to achieve an unprecedented control of the pump depletion: pump-to-frequency comb conversion efficiencies of up to 55% of the input pump power is experimentally demonstrated with a soliton crystal comb. We assess the robustness of the proposed on-chip geometry by generating a large variety of dissipative Kerr soliton combs, which require a lower amount of pump power to be accessed, when compared with an isolated micro-ring resonator with identical parameters. Micro-resonators with feedback enable accessing new regimes of coherent soliton comb generation, and are well suited for comb applications in astronomy, spectroscopy and telecommunications. Increasing the conversion efficiency of soliton crystals will enable further application of optical frequency comb. Here the authors engineer an hybrid Mach-Zehnder micro-ring resonator to achieve 80% pump-to-comb conversion efficiency based on dissipative Kerr solitons.

    Download full text (pdf)
    fulltext
  • 4.
    Gautam, Rekha
    et al.
    San Francisco State Univ, CA 94132 USA; Vanderbilt Univ, TN 37235 USA.
    Bezryadina, Anna
    San Francisco State Univ, CA 94132 USA; Calif State Univ Northridge, CA 91330 USA.
    Xiang, Yinxiao
    San Francisco State Univ, CA 94132 USA; Vanderbilt Univ, TN 37235 USA.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Liang, Yi
    San Francisco State Univ, CA 94132 USA; Guangxi Univ, Peoples R China.
    Liang, Guo
    San Francisco State Univ, CA 94132 USA; Shangqiu Normal Univ, Peoples R China.
    Lamstein, Josh
    San Francisco State Univ, CA 94132 USA.
    Perez, Nicolas
    Calif State Univ Northridge, CA 91330 USA.
    Wetzel, Benjamin
    Univ Limoges, France.
    Morandotti, Roberto
    Univ Quebec, Canada; Univ Elect Sci and Technol China, Peoples R China.
    Chen, Zhigang
    San Francisco State Univ, CA 94132 USA; Nankai Univ, Peoples R China; Nankai Univ, Peoples R China.
    Nonlinear optical response and self-trapping of light in biological suspensions2020In: ADVANCES IN PHYSICS-X, ISSN 2374-6149, Vol. 5, no 1Article, review/survey (Refereed)
    Abstract [en]

    In the past decade, the development of artificial materials exhibiting novel optical properties has become a major scientific endeavor. One particularly interesting system is synthetic soft matter, which plays a central role in numerous fields ranging from life sciences, chemistry to condensed matter and biophysics. In this paper, we review briefly the optical force-induced nonlinearities in colloidal suspensions, which can give rise to nonlinear self-trapping of light for enhanced propagation through otherwise highly scattering media such as dielectric and plasmonic nanosuspensions. We then focus on discussing our recent work with respect to nonlinear biological suspensions, including self-trapping of light in colloidal suspensions of marine bacteria and red blood cells, where the nonlinear response is largely attributed to the optical forces acting on the cells. Although it is commonly believed that biological media cannot exhibit high optical non-linearity, self-focusing of light and formation of soliton-like wave-guides in bio-soft matter have been observed. Furthermore, we present preliminary results on biological waveguiding and sensing, and discuss some perspectives towards biomedical applications. The concept may be developed for subsequent studies and techniques in situations when low scattering and deep penetration of light is desired.

    Download full text (pdf)
    fulltext
  • 5.
    Gautam, Rekha
    et al.
    San Francisco State Univ, CA 94132 USA; Vanderbilt Univ, TN 37240 USA.
    Xiang, Yinxiao
    San Francisco State Univ, CA 94132 USA; Nankai Univ, Peoples R China; Nankai Univ, Peoples R China.
    Lamstein, Josh
    San Francisco State Univ, CA 94132 USA.
    Liang, Yi
    San Francisco State Univ, CA 94132 USA; Guangxi Univ, Peoples R China.
    Bezryadina, Anna
    San Francisco State Univ, CA 94132 USA; Calif State Univ Northridge, CA 91330 USA.
    Liang, Guo
    San Francisco State Univ, CA 94132 USA.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Univ Quebec, Canada.
    Wetzel, Benjamin
    Univ Quebec, Canada; Univ Sussex, England.
    Preece, Daryl
    Univ Calif Irvine, CA USA.
    White, Adam
    San Francisco State Univ, CA 94132 USA.
    Silverman, Matthew
    San Francisco State Univ, CA 94132 USA.
    Kazarian, Susan
    San Francisco State Univ, CA 94132 USA.
    Xu, Jingjun
    Nankai Univ, Peoples R China.
    Morandotti, Roberto
    Univ Quebec, Canada; Univ Elect Sci and Tech China, Peoples R China; ITMO Univ, Russia.
    Chen, Zhigang
    San Francisco State Univ, CA 94132 USA; Nankai Univ, Peoples R China; Nankai Univ, Peoples R China.
    Optical force-induced nonlinearity and self-guiding of light in human red blood cell suspensions2019In: Light: Science & Applications, ISSN 2095-5545, E-ISSN 2047-7538, Vol. 8, article id 31Article in journal (Refereed)
    Abstract [en]

    Osmotic conditions play an important role in the cell properties of human red blood cells (RBCs), which are crucial for the pathological analysis of some blood diseases such as malaria. Over the past decades, numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes. Here, we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions. Specifically, we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions, where the strength of the optical nonlinearity increases with osmotic pressure on the cells. This tunable nonlinearity is attributed to optical forces, particularly the forward-scattering and gradient forces. Interestingly, in aged blood samples (with lysed cells), a notably different nonlinear behavior is observed due to the presence of free hemoglobin. We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations. Our work on light self-guiding through scattering bio-soft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis.

    Download full text (pdf)
    fulltext
  • 6.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Matsko, Andrey B.
    CALTECH, CA 91109 USA.
    Taheri, Hossein
    Univ Calif Riverside, CA 92521 USA.
    Gating Artefact in the Coupled-Wave-Equations Modeling of Classical and Quantum Kerr Nonlinear Effects2021In: 2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE , 2021Conference paper (Refereed)
    Abstract [en]

    We show that the coupled-wave-equations numerical modeling of frequency combs, considered equivalent to the split-step integration of the nonlinear Schrodinger equation family, entails an inherent gating artefact capable of disguising physically unstable states as stable. (C) 2021 The Author(s)

  • 7.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Univ Brescia, Italy.
    Parra-Rivas, P.
    Univ Libre Bruxelles, Belgium; Univ Leuven, Belgium.
    Bernard, M.
    Univ Brescia, Italy.
    Leo, F.
    Univ Libre Bruxelles, Belgium.
    Gelens, L.
    Univ Leuven, Belgium.
    Wabnitz, S.
    Univ Brescia, Italy; Sapienza Univ Roma, Italy.
    Quadratic cavity soliton optical frequency combs2019In: 2019 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    We theoretically investigate the formation of frequency combs in a dispersive second-harmonic generation cavity system, and predict the existence of quadratic cavity solitons in the absence of a temporal walk-off. (C) 2019 The Author(s)

  • 8.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Univ Brescia, Italy.
    Parra-Rivas, Pedro
    Univ Libre Bruxelles, Belgium; Univ Leuven, Belgium.
    Bernard, Martino
    Univ Brescia, Italy.
    Leo, Francois
    Univ Libre Bruxelles, Belgium.
    Gelens, Lendert
    Univ Leuven, Belgium.
    Wabnitz, Stefan
    Univ Brescia, Italy; CNR INO, Italy.
    Quadratic soliton combs in doubly resonant second-harmonic generation2018In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 43, no 24, p. 6033-6036Article in journal (Refereed)
    Abstract [en]

    We report a theoretical investigation of quadratic frequency combs in a dispersive second-harmonic generation cavity system. We identify different dynamical regimes and demonstrate that the same system can exhibit both bright and dark localized cavity solitons in the absence of a temporal walk-off. (c) 2018 Optical Society of America

    Download full text (pdf)
    fulltext
  • 9.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Parra-Rivas, Pedro
    Sapienza Univ. di Roma, Italy.
    Wabnitz, Stefan
    Sapienza Univ. di Roma, Italy.
    Bistable solitons in third-harmonic generation frequency combs2023In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE , 2023, Vol. 12407, article id 1240707Conference paper (Refereed)
    Abstract [en]

    We present a theoretical model for describing dissipative solitons and optical frequency combs formation in a dispersive and nonlinear χ(3)-based cavity system that is phase-matched for third-harmonic generation. We consider the importance of the stability properties of the homogeneous solution in generating various types of multi-frequency combs, and demonstrate a novel type of bistable cavity solitons.

  • 10.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Sapienza Univ Roma, Italy.
    Parra-Rivas, Pedro
    Sapienza Univ Roma, Italy.
    Wabnitz, Stefan
    Sapienza Univ Roma, Italy.
    Modeling of dual frequency combs and bistable solitons in third-harmonic generation2023In: Communications Physics, E-ISSN 2399-3650, Vol. 6, no 1, article id 59Article in journal (Refereed)
    Abstract [en]

    Third-harmonic generation frequency combs grant telecom pump laser sources the direct and simultaneous access to both the near infrared and the visible spectral regions. The authors model the broadband and temporally dispersive dual-comb generation, and identify conditions for accessing a regime supporting two distinct and coexisting cavity solitons. Phase-matching of the third-harmonic generation process can be used to extend the emission of radiation from Kerr microresonators into new spectral regions far from the pump wavelength. Here, we present a theoretical mean-field model for optical frequency combs in a dissipative and nonlinear chi((3))-based cavity system with parametric coupling between fundamental and third-harmonic waves. We investigate temporally dispersive dual-comb generation of phase-matched combs with broad bandwidth and anomalous dispersion of the fundamental field, individuating conditions for accessing a multistable regime that simultaneously supports two types of coupled bright cavity solitons. These bistable cavity solitons coexist for the same pump power and frequency detuning, while featuring dissimilar amplitudes of their individual field components. Third-harmonic generation frequency combs grant telecom pump laser sources a simultaneous and direct access to both the near-infrared and the visible regions, which may prove advantageous for the development of optical clocks and sensing applications.

    Download full text (pdf)
    fulltext
  • 11.
    Hansson, Tobias
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Tonello, Alessandro
    Université de Limoges, XLIM, Limoges, France.
    Mansuryan, Tigran
    Université de Limoges, XLIM, Limoges, France.
    Mangini, Fabio
    Dipartimento di Ingegneria dell’Informazione, University of Brescia, Brescia, Italy.
    Zitelli, Mario
    Dipartimento di Ingegneria dell’Informazione, University of Brescia, Brescia, Italy.
    Ferraro, Mario
    Dipartimento di Ingegneria dell’Informazione, Elettronica e Telecomunicazioni, Sapienza University of Rome, Rome, Italy.
    Niang, Alioune
    Dipartimento di Ingegneria dell’Informazione, University of Brescia, Brescia, Italy.
    Crescenzi, Rocco
    Dipartimento di Ingegneria dell’Informazione, Elettronica e Telecomunicazioni, Sapienza University of Rome, , Italy.
    Wabnitz, Stefan
    Dipartimento di Ingegneria dell’Informazione, Elettronica e Telecomunicazioni, Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy; Novosibirsk State University, Pirogova 1, Novosibirsk 630090, Russia.
    Couderc, Vincent
    Université de Limoges, Limoges, France.
    Nonlinear beam self-imaging and self-focusing dynamics in a GRIN multimode optical fiber: theory and experiments2020In: Optics Express, E-ISSN 1094-4087, Vol. 28, no 16, p. 24005-24021Article in journal (Refereed)
    Abstract [en]

    Beam self-imaging in nonlinear graded-index multimode optical fibers is of interest for many applications, such as implementing a fast saturable absorber mechanism in fiber lasers via multimode interference. We obtain a new exact solution for the nonlinear evolution of first and second order moments of a laser beam of arbitrary transverse shape carried by a graded-index multimode fiber. We have experimentally directly visualized the longitudinal evolution of beam self-imaging by means of femtosecond laser pulse propagation in both the anomalous and the normal dispersion regime of a standard telecom graded-index multimode optical fiber. Light scattering out of the fiber core via visible photo-luminescence emission permits us to directly measure the self-imaging period and the beam dynamics. Spatial shift and splitting of the self-imaging process under the action of self-focusing are also revealed.

    Download full text (pdf)
    fulltext
  • 12.
    Mangini, F.
    et al.
    University of Brescia, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Tonello, A.
    Université de Limoges, XLIM, France.
    Mansuryan, T.
    Université de Limoges, XLIM, France.
    Zitelli, M.
    Sapienza University of Rome, Italy.
    Ferraro, M.
    Sapienza University of Rome, Italy.
    Niang, A.
    University of Brescia, Italy.
    Crescenzi, R.
    Sapienza University of Rome, Italy.
    Wabnitz, S.
    Sapienza University of Rome, Italy.
    Couderc, V.
    Université de Limoges, XLIM, France.
    Self-imaging dynamics in nonlinear GRIN multimode optical fibers2020In: Optics InfoBase Conference Papers, Optica Publishing Group , 2020, article id FTh1E.4Conference paper (Refereed)
    Abstract [en]

    We study nonlinear self-imaging dynamics in graded-index multimode optical fibers. Side-scattering of light that accompanies the propagation of intense femtosecond pulses permits us to directly measure the self-imaging period.

  • 13.
    Mosca, Simona
    et al.
    Ist Nazl Ottica, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Parisi, Maria
    Ist Nazl Ottica, Italy.
    Spectral Broadening in a Continuously Pumped Singly Resonant Second-Harmonic Cavity2021In: Applied Sciences, E-ISSN 2076-3417, Vol. 11, no 15, article id 7122Article in journal (Refereed)
    Abstract [en]

    Featured Application The spectral broadening observed in the designed second-order nonlinear optical system is suitable to be miniaturized as a chip-scale multifrequency source for applications in metrology, sensing, and telecommunication. Optical frequency comb synthesizers with a wide spectral range are an essential tool for many research areas such as spectroscopy, precision metrology, optical communication, and sensing. Recent studies have demonstrated the direct generation of frequency combs, via second-order processes, that are centered on two different spectral regions separated by an octave. Here, we present the capability of optical quadratic frequency combs for broad-bandwidth spectral emission in unexplored regimes. We consider comb formation under phase-matched conditions in a continuous-wave pumped singly resonant second-harmonic cavity, with large intracavity power and control of the detuning over several cavity linewidths. The spectral analysis reveals quite distinctive sidebands that arise far away from the pump, singularly or in a mixed regime together with narrowband frequency combs. Notably, by increasing the input power, the optical frequency lines evolve into widely spaced frequency clusters, and at maximum power, they appear in a wavelength range spanning up to 100 nm. The obtained results demonstrate the capacity of second-order nonlinearities to produce direct comb within a wide range of wavelengths.

    Download full text (pdf)
    fulltext
  • 14.
    Okawachi, Yoshitomo
    et al.
    Columbia Univ, NY 10027 USA.
    Yu, Mengjie
    Harvard Univ, MA 02138 USA.
    Desiatov, Boris
    Harvard Univ, MA 02138 USA.
    Kim, Bok Young
    Columbia Univ, NY 10027 USA.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Loncar, Marko
    Harvard Univ, MA 02138 USA.
    Gaeta, Alexander L.
    Columbia Univ, NY 10027 USA.
    Chip-based self-referencing using integrated lithium niobate waveguides2020In: Optica, ISSN 2334-2536, Vol. 7, no 6, p. 702-707Article in journal (Refereed)
    Abstract [en]

    The measurement and stabilization of the carrier-envelope offset frequency f(CEO) via self-referencing is paramount for optical frequency comb generation, which has revolutionized precision frequency metrology, spectroscopy, and optical clocks. Over the past decade, the development of chip-scale platforms has enabled compact integrated waveguides for supercontinuum generation. However, there is a critical need for an on-chip self-referencing system that is adaptive to different pump wavelengths, requires low pulse energy, and does not require complicated processing. Here, we demonstrate efficient f(CEO) stabilization of a modelocked laser with only 10(7) pJ of pulse energy via self-referencing in an integrated lithium niobate waveguide. We realize an f-2f interferometer through second-harmonic generation and subsequent supercontinuum generation in a single dispersion-engineered waveguide with a stabilization performance equivalent to a conventional off-chip module. The f(CEO) beatnote is measured over a pump wavelength range of 70 nm. We theoretically investigate our system using a single nonlinear envelope equation with contributions from both second and third-order nonlinearities. Our modeling reveals rich ultrabroadband nonlinear dynamics and confirms that the initial second-harmonic generation followed by supercontinuum generation with the remaining pump is responsible for the generation of a strong f(CEO) signal as compared to a traditional f-2f interferometer. Our technology provides a highly simplified system that is robust, low in cost, and adaptable for precision metrology for use outside a research laboratory. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

  • 15.
    Parra-Rivas, P.
    et al.
    University of Leuven, Belgium.
    Gelens, L.
    University of Leuven, Belgium.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Wabnitz, S.
    Sapienza University of Rome, Italy.
    Leo, F.
    Université libre de Bruxelles, Belgium.
    Locking of Domain Walls and Quadratic Frequency Combs in Doubly Resonant Optical Parametric Oscillators2019Conference paper (Refereed)
    Abstract [en]

    The formation of frequency combs (FCs) in high-Q microresonators with Kerr type of nonlinearity has attracted a lot of attention in the past decade [1]. Recently it has been shown that FCs can be also generated in dissipative dispersive cavities with quadratic nonlinearities [2,3], opening a new possibility of generating combs in previously unattainable spectral regions. Previous work has shown that modulational instability (MI) induces pattern and FC formation in degenerate optical parametric oscillators (OPOs) [4]. However, the existence of dissipative solitons or localized structures (LSs) is still unclear. In this work we present the locking of domain walls (DWs) as an alternative mechanism to MI for the formation of LSs and FCs. DWs have been widely studied in the context of Kerr cavities and diffractive OPO cavities [5,6]. Here we show that similar structures can arise in dispersive quadratic cavities. To illustrate this, we consider a dispersive cavity with a quadratic medium phase matched for degenerate OPO and driven by the field B in at the frequency 2ω 0 in a doubly resonant configuration. The formation of dissipative structures in this type of cavity can be described by an infinite map for the slowly varying electric field envelopes A m , and B m , that are centered at frequency ω 0 and 2ω 0 , respectively [4], where m indicates the cavity round-trip number. With this map one may numerically explore the dynamics of the system. For example, Fig. 1(a)-(b) show the formation of a dissipative structure, after a sufficient number of round-trips (m = 2 · 10 4 ), from an initial noisy background. We see that i) both fields are phase locked and drift at the same velocity; ii) for the A field one can identify a sequence of DWs connecting two different, and coexisting, CW states, that form a disordered structure. Furthermore, the latter is composed of a sequence of LSs of different widths. One of them, LS 4 , is plotted in panel (c). We demonstrate that this ty...

  • 16.
    Parra-Rivas, Pedro
    et al.
    Univ Libre Bruxelles, Belgium; Univ Leuven, Belgium.
    Gelens, Lendert
    Univ Leuven, Belgium.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Wabnitz, Stefan
    Sapienza Univ Rome, Italy; CNR, Italy.
    Leo, Francois
    Univ Libre Bruxelles, Belgium.
    Frequency comb generation through the locking of domain walls in doubly resonant dispersive optical parametric oscillators2019In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 44, no 8, p. 2004-2007Article in journal (Refereed)
    Abstract [en]

    In this Letter we theoretically investigate the formation of localized temporal dissipative structures, and their corresponding frequency combs in doubly resonant dispersive optical parametric oscillators. We derive a nonlocal mean field model, and show that domain wall locking allows for the formation of stable coherent optical frequency combs. (C) 2019 Optical Society of America

  • 17.
    Ricciardi, Iolanda
    et al.
    CNR-INO, Istituto Nazionale di Ottica, Italy; INFN, Istituto Nazionale di Fisica Nucleare, Italy.
    Maddaloni, Pasquale
    CNR-INO, Istituto Nazionale di Ottica, Italy; INFN, Istituto Nazionale di Fisica Nucleare, Italy.
    De Natale, Paolo
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Erkintalo, Miro
    The University of Auckland, New Zealand.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Arie, Ady
    Tel-Aviv University, Israel.
    Wabnitz, Stefan
    CNR-INO, Istituto Nazionale di Ottica, Italy; Sapienza Università di Roma, Italy.
    De Rosa, Maurizio
    CNR-INO, Istituto Nazionale di Ottica, Italy; INFN, Istituto Nazionale di Fisica Nucleare, Italy.
    Optical frequency combs in dispersion-controlled doubly resonant second-harmonic generation2022In: Optics Express, E-ISSN 1094-4087, Vol. 30, no 25, p. 45694-45704Article in journal (Refereed)
    Abstract [en]

    We report on the experimental realization and a systematic study of optical frequency comb generation in doubly resonant intracavity second harmonic generation (SHG). The efficiency of intracavity nonlinear processes usually benefits from the increasing number of resonating fields. Yet, achieving the simultaneous resonance of different fields may be technically complicated, all the more when a phase matching condition must be fulfilled as well. In our cavity we can separately control the resonance condition for the fundamental and its second harmonic, by simultaneously acting on an intracavity dispersive element and on a piezo-mounted cavity mirror, without affecting the quasi-phase matching condition. In addition, by finely adjusting the laser-to-cavity detuning, we are able to observe steady comb emission across the whole resonance profile, revealing the multiplicity of comb structures, and the substantial role of thermal effects on their dynamics. Lastly, we report the results of numerical simulations of comb dynamics, which include photothermal effects, finding a good agreement with the experimental observations. Our system provides a framework for exploring the richness of comb dynamics in doubly resonant SHG systems, assisting the design of chip-scale quadratic comb generators.

    Download full text (pdf)
    fulltext
  • 18.
    Ricciardi, Iolanda
    et al.
    CNR, Italy; Complesso Univ MS Angelo, Italy.
    Mosca, Simona
    CNR, Italy.
    Parisi, Maria
    CNR, Italy.
    Leo, Francois
    Univ Libre Bruxelles, Belgium.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Erkintalo, Miro
    Dodd Walls Ctr Photon and Quantum Technol, New Zealand; Univ Auckland, New Zealand.
    Maddaloni, Pasquale
    CNR, Italy; Complesso Univ MS Angelo, Italy.
    De Natale, Paolo
    CNR, Italy.
    Wabnitz, Stefan
    CNR, Italy; Sapienza Univ Roma, Italy; Novosibirsk State Univ, Russia.
    De Rosa, Maurizio
    CNR, Italy; Complesso Univ MS Angelo, Italy.
    Optical Frequency Combs in Quadratically Nonlinear Resonators2020In: MICROMACHINES, Vol. 11, no 2, article id 230Article, review/survey (Refereed)
    Abstract [en]

    Optical frequency combs are one of the most remarkable inventions in recent decades. Originally conceived as the spectral counterpart of the train of short pulses emitted by mode-locked lasers, frequency combs have also been subsequently generated in continuously pumped microresonators, through third-order parametric processes. Quite recently, direct generation of optical frequency combs has been demonstrated in continuous-wave laser-pumped optical resonators with a second-order nonlinear medium inside. Here, we present a concise introduction to such quadratic combs and the physical mechanism that underlies their formation. We mainly review our recent experimental and theoretical work on formation and dynamics of quadratic frequency combs. We experimentally demonstrated comb generation in two configurations: a cavity for second harmonic generation, where combs are generated both around the pump frequency and its second harmonic and a degenerate optical parametric oscillator, where combs are generated around the pump frequency and its subharmonic. The experiments have been supported by a thorough theoretical analysis, aimed at modelling the dynamics of quadratic combs, both in frequency and time domains, providing useful insights into the physics of this new class of optical frequency comb synthesizers. Quadratic combs establish a new class of efficient frequency comb synthesizers, with unique features, which could enable straightforward access to new spectral regions and stimulate novel applications.

  • 19.
    Ricciardi, Iolanda
    et al.
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Mosca, Simona
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Parisi, Maria
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Maddaloni, Pasquale
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Natale, Paolo De
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Erkintalo, Miro
    The University of Auckland, New Zealand.
    Leo, François
    Université libre de Bruxelles, Belgium.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Arie, Ady
    Tel-Aviv University, Israel.
    Wabnitz, Stefan
    Sapienza Università di Roma, Italy.
    Rosa, Maurizio De
    CNR-INO, Istituto Nazionale di Ottica, Italy.
    Experimental Observation of Optical Frequency Combs in Doubly Resonant Second Harmonic Generation2019Conference paper (Refereed)
    Abstract [en]

    Continuously-driven microresonators, whose nonlinear response is dominated by the third-order Kerr nonlinearity, have proven to be valid alternatives to comb sources based on femtosecond mode-locked lasers [1]. More recenlty, the direct generation of optical frequency combs (OFCs) entirely through quadratic interactions has also been demonstrated in singly resonant cavity second harmonic generation (SHG) and in cw pumped nearly degenerate optical parametric oscillation [2,3]. Interestingly, theoretical studies on doubly resonant cavity SHG predicted the emergence of OFCs with a much lower threshold with respect to the singly resonant configurations, as well as rich nonlinear dynamics [4].

  • 20.
    Talenti, Francesco Rinaldo
    et al.
    Sapienza Univ Rome, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Wabnitz, Stefan
    Sapienza Univ Rome, Italy; CNR INO, Italy.
    Novel generation schemes for stable soliton states in optical microcavities2022In: 2022 ITALIAN CONFERENCE ON OPTICS AND PHOTONICS (ICOP), IEEE , 2022Conference paper (Refereed)
    Abstract [en]

    The excitation of Kerr optical frequency combs (OFC) is frequently non-deterministic and remains a cumber-some problem in many practical situations. While standard techniques to generate Kerr solitons in passive resonators employ a continuous wave pump, recently pulsed pumping has also been proposed. In this study we individuate and classify OFC states in a phase space defined by an experimental set of coordinates and triggered by a general super-Gaussian chirped driving field. Our numerical analysis shows how the soliton drifts caused by the phase modulation of the input field accelerate the dynamics and convergence towards a stable soliton state.

  • 21.
    Wabnitz, S.
    et al.
    Sapienza Univ Rome, Italy; CNR INO, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Parra-Rivas, P.
    ULB, Belgium.
    Leo, F.
    ULB, Belgium.
    Erkintalo, M.
    Univ Auckland, New Zealand.
    Mosca, S.
    CNR INO, Italy.
    Parisi, M.
    CNR INO, Italy.
    Ricciardi, I.
    CNR INO, Italy.
    De Rosa, M.
    CNR INO, Italy.
    Quadratic Optical Frequency Combs: Towards a New Platform for Multi-Octave Microcombs2020In: INTERNATIONAL CONFERENCE LASER OPTICS 2020 (ICLO 2020), IEEE , 2020Conference paper (Refereed)
    Abstract [en]

    Optical frequency comb sources based on three-wave-mixing in quadratic nonlinear materials allow for reduced pump power threshold and extended spectral coverage. We review recent progress on quadratic optical frequency combs based on second-harmonic generation and optical parametric oscillation.

  • 22.
    Wabnitz, Stefan
    et al.
    Sapienza Univ Rome, Italy.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Parra-Rivas, Pedro
    Univ Libre Bruxelles, Belgium.
    Leo, Francois
    Univ Libre Bruxelles, Belgium.
    Erkintalo, Miro
    Univ Auckland, New Zealand.
    Mosca, Simona
    CNR, Italy.
    Parisi, Maria
    CNR, Italy.
    Ricciardi, Iolanda
    CNR, Italy.
    De Rosa, Maurizio
    CNR, Italy.
    Quadratic Optical Frequency Combs2019In: 2019 IEEE PHOTONICS CONFERENCE (IPC), IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    Optical frequency comb sources based on quadratic nonlinearities provide an interesting alternative to Kerr combs in terms of reduced pump power requirements and extended spectral coverage. We review theory and recent experiments of quadratic optical frequency combs based on second-harmonic generation and optical parametric oscillation.

  • 23.
    Zitelli, M.
    et al.
    Sapienza Univ Rome, Italy.
    Ferraro, M.
    Sapienza Univ Rome, Italy.
    Mangini, F.
    Univ Brescia, Italy.
    Leggio, L.
    Sapienza Univ Rome, Italy.
    Kharenko, D. S.
    Novosibirsk State Univ, Russia.
    Niang, A.
    Univ Brescia, Italy.
    Tonello, A.
    Univ Limoges, France.
    Couderc, V
    Univ Limoges, France.
    Hansson, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Wabnitz, S.
    Sapienza Univ Rome, Italy; Novosibirsk State Univ, Russia.
    Spatiotemporal guided bullets in multimode fiber2021In: NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XX, SPIE-INT SOC OPTICAL ENGINEERING , 2021, Vol. 11670, article id 1167018Conference paper (Refereed)
    Abstract [en]

    Beam self-imaging of ultrashort pulses in nonlinear graded-index (GRIN) multimode optical fibers is of interest for many applications, including spatiotemporal mode-locking in fiber lasers. We obtained a new analytical description for the nonlinear evolution of a laser beam of arbitrary transverse shape propagating in a GRIN fiber. The longitudinal beam evolution could be directly visualized by means of femtosecond laser pulses, propagating in the anomalous or in the normal dispersion regime, leading to light scattering out of the fiber core via the emission of blue photo-luminescence. As the critical power for self-focusing is approached and even surpassed, a host of previously undisclosed nonlinear effects is revealed, including strong multiphoton absorption by oxygen-deficiency center defects and Germanium inclusions, splitting and shifting of the self-imaging period, filamentation, and conical emission of the guided light bullets. We discovered that nonlinear loss has a profound influence on the process of high-order spatiotemporal soliton fission. The beam energy carried by the fiber is clamped to a fixed value, and nonlinear bullet attractors with suppressed Raman frequency shift and fixed temporal duration are generated, leading to highly efficient frequency conversion of the input near-infrared femtosecond pulses into mid-infrared multimode solitons.

1 - 23 of 23
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf