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Chia-chien Huang - One of the best experts on this subject based on the ideXlab platform.

  • theoretical analysis of mode conversion by Refractive Index Perturbation based on a single tilted slot on a silicon waveguide
    Optics Express, 2020
    Co-Authors: Chia-chih Huang, Chia-chien Huang
    Abstract:

    We propose a compact mode converter operating at the mid-infrared wavelength of 3.4 µm, comprising an etched parallelogram slot filled with silicon nitride on a silicon-on-calcium fluoride platform. The tilted slot introduces transverse and longitudinal Index Perturbations on the waveguide eigenmodes, achieving mode conversion in the propagation direction. Differing from previous reports using massive parameter sweep, we provide analytical formulas to determine geometry parameters by considering the modified phase-matching condition and the profiles of coupling coefficient of coupled-mode theory. Rigorous 3D numerical examples demonstrate the transverse electric (TE)0-to-TE1, TE0-to-TE2, TE0-to-TE3, and TE0-to-TE4 converters to achieve conversion efficiencies (inter-modal crosstalk [CT] values) of >92.7% ( 91.7% ( 88.2% ( 75.8% ( 93%. Converter device lengths range from 16.84 to 24.61 µm for TE0-to-TE1 to TE0-to-TE4, respectively. Over a broadband wavelength of 100 nm, the conversion efficiency, power transmission, and maximum inter-modal CT are almost >80%, >90%, and <−10 dB, respectively. Also, the fabrication tolerance of the proposed structure is addressed. The proposed model can not only realize arbitrary mode-order conversion but extend to other wavelength bands. To validate the feasibility of our model, the numerical results of our device operating at the wavelength of 1.55 µm are also offered and compared with those of other reports. The proposed idea may pave a new approach to designing mode converters with arbitrary geometries.

  • Theoretical analysis of mode conversion by Refractive-Index Perturbation based on a single tilted slot on a silicon waveguide
    Optics express, 2020
    Co-Authors: Chia-chih Huang, Chia-chien Huang
    Abstract:

    We propose a compact mode converter operating at the mid-infrared wavelength of 3.4 µm, comprising an etched parallelogram slot filled with silicon nitride on a silicon-on-calcium fluoride platform. The tilted slot introduces transverse and longitudinal Index Perturbations on the waveguide eigenmodes, achieving mode conversion in the propagation direction. Differing from previous reports using massive parameter sweep, we provide analytical formulas to determine geometry parameters by considering the modified phase-matching condition and the profiles of coupling coefficient of coupled-mode theory. Rigorous 3D numerical examples demonstrate the transverse electric (TE)0-to-TE1, TE0-to-TE2, TE0-to-TE3, and TE0-to-TE4 converters to achieve conversion efficiencies (inter-modal crosstalk [CT] values) of >92.7% ( 91.7% ( 88.2% ( 75.8% ( 93%. Converter device lengths range from 16.84 to 24.61 µm for TE0-to-TE1 to TE0-to-TE4, respectively. Over a broadband wavelength of 100 nm, the conversion efficiency, power transmission, and maximum inter-modal CT are almost >80%, >90%, and

Daniele Faccio - One of the best experts on this subject based on the ideXlab platform.

  • Experimental evidence of analogue Hawking radiation from ultrashort laser pulse filaments
    New Journal of Physics, 2011
    Co-Authors: E. Rubino, Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, V. G. Sala, Miroslav Kolesik, Matteo Clerici, Daniele Faccio
    Abstract:

    Curved space–times and, in particular, event horizons of astrophysical black holes are expected to excite the quantum vacuum and give rise to an emission of quanta known as Hawking radiation. Remarkably, many physical systems may be considered analogous to black holes and as such hold promise for the detection of Hawking radiation. In particular, recent progress in the field of transformation optics, i.e. the description of optical systems in terms of curved space–time geometries, has led to a detailed description of methods for generating, via superluminal dielectrics, a blocking horizon for photons. Our measurements highlight the emission of photons from a moving Refractive Index Perturbation induced by a laser pulse that is in quantitative agreement with the Hawking model. This opens an intriguing and readily accessible observation window into quantum field theory in curved space–time geometries.

  • Quantum radiation from superluminal Refractive-Index Perturbations.
    Physical review letters, 2010
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, V. G. Sala, Daniele Faccio
    Abstract:

    We analyze in detail photon production induced by a superluminal Refractive-Index Perturbation in realistic experimental operating conditions. The interaction between the Refractive-Index Perturbation and the quantum vacuum fluctuations of the electromagnetic field leads to the production of photon pairs.

  • Analogue Gravity and ultrashort laser pulse filamentation
    EPL (Europhysics Letters), 2010
    Co-Authors: Daniele Faccio, Sergio L. Cacciatori, Vittorio Gorini, V. G. Sala, Alessandro Averchi, A. Lotti, Miroslav Kolesik, Jerome V. Moloney
    Abstract:

    Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a moving Refractive Index Perturbation which modifies the space-time geometry as seen by co-propagating light rays. We study the analogue geometry induced by the filament and show that one of the most evident features of filamentation, namely conical emission, may be precisely reconstructed from the geodesics. We highlight the existence of favorable conditions for the study of analogue black hole kinematics and Hawking type radiation.

  • Quantum Aspects of Ultrashort Laser Pulse Filamentation - Hawking Radiation and the Dynamical Casimir Effect
    Advanced Photonics & Renewable Energy, 2010
    Co-Authors: Daniele Faccio, Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, V. G. Sala, Vittorio Gorini
    Abstract:

    Ultrashort laser pulse filamentation induces a Refractive Index Perturbation which is described in terms of a curved space-time metric. We outline the details of this idea and we give a progress report on experimental measurements.

Chia-chih Huang - One of the best experts on this subject based on the ideXlab platform.

  • theoretical analysis of mode conversion by Refractive Index Perturbation based on a single tilted slot on a silicon waveguide
    Optics Express, 2020
    Co-Authors: Chia-chih Huang, Chia-chien Huang
    Abstract:

    We propose a compact mode converter operating at the mid-infrared wavelength of 3.4 µm, comprising an etched parallelogram slot filled with silicon nitride on a silicon-on-calcium fluoride platform. The tilted slot introduces transverse and longitudinal Index Perturbations on the waveguide eigenmodes, achieving mode conversion in the propagation direction. Differing from previous reports using massive parameter sweep, we provide analytical formulas to determine geometry parameters by considering the modified phase-matching condition and the profiles of coupling coefficient of coupled-mode theory. Rigorous 3D numerical examples demonstrate the transverse electric (TE)0-to-TE1, TE0-to-TE2, TE0-to-TE3, and TE0-to-TE4 converters to achieve conversion efficiencies (inter-modal crosstalk [CT] values) of >92.7% ( 91.7% ( 88.2% ( 75.8% ( 93%. Converter device lengths range from 16.84 to 24.61 µm for TE0-to-TE1 to TE0-to-TE4, respectively. Over a broadband wavelength of 100 nm, the conversion efficiency, power transmission, and maximum inter-modal CT are almost >80%, >90%, and <−10 dB, respectively. Also, the fabrication tolerance of the proposed structure is addressed. The proposed model can not only realize arbitrary mode-order conversion but extend to other wavelength bands. To validate the feasibility of our model, the numerical results of our device operating at the wavelength of 1.55 µm are also offered and compared with those of other reports. The proposed idea may pave a new approach to designing mode converters with arbitrary geometries.

  • Theoretical analysis of mode conversion by Refractive-Index Perturbation based on a single tilted slot on a silicon waveguide
    Optics express, 2020
    Co-Authors: Chia-chih Huang, Chia-chien Huang
    Abstract:

    We propose a compact mode converter operating at the mid-infrared wavelength of 3.4 µm, comprising an etched parallelogram slot filled with silicon nitride on a silicon-on-calcium fluoride platform. The tilted slot introduces transverse and longitudinal Index Perturbations on the waveguide eigenmodes, achieving mode conversion in the propagation direction. Differing from previous reports using massive parameter sweep, we provide analytical formulas to determine geometry parameters by considering the modified phase-matching condition and the profiles of coupling coefficient of coupled-mode theory. Rigorous 3D numerical examples demonstrate the transverse electric (TE)0-to-TE1, TE0-to-TE2, TE0-to-TE3, and TE0-to-TE4 converters to achieve conversion efficiencies (inter-modal crosstalk [CT] values) of >92.7% ( 91.7% ( 88.2% ( 75.8% ( 93%. Converter device lengths range from 16.84 to 24.61 µm for TE0-to-TE1 to TE0-to-TE4, respectively. Over a broadband wavelength of 100 nm, the conversion efficiency, power transmission, and maximum inter-modal CT are almost >80%, >90%, and

Sergio L. Cacciatori - One of the best experts on this subject based on the ideXlab platform.

  • Experimental evidence of analogue Hawking radiation from ultrashort laser pulse filaments
    New Journal of Physics, 2011
    Co-Authors: E. Rubino, Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, V. G. Sala, Miroslav Kolesik, Matteo Clerici, Daniele Faccio
    Abstract:

    Curved space–times and, in particular, event horizons of astrophysical black holes are expected to excite the quantum vacuum and give rise to an emission of quanta known as Hawking radiation. Remarkably, many physical systems may be considered analogous to black holes and as such hold promise for the detection of Hawking radiation. In particular, recent progress in the field of transformation optics, i.e. the description of optical systems in terms of curved space–time geometries, has led to a detailed description of methods for generating, via superluminal dielectrics, a blocking horizon for photons. Our measurements highlight the emission of photons from a moving Refractive Index Perturbation induced by a laser pulse that is in quantitative agreement with the Hawking model. This opens an intriguing and readily accessible observation window into quantum field theory in curved space–time geometries.

  • Dielectric black holes induced by a Refractive Index Perturbation and the Hawking effect
    Physical Review D, 2011
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, D. Faccio
    Abstract:

    We consider a 4D model for photon production induced by a Refractive Index Perturbation in a dielectric medium. We show that, in this model, we can infer the presence of a Hawking type effect. This prediction shows up both in the analogue Hawking framework, which is implemented in the pulse frame and relies on the peculiar properties of the effective geometry in which quantum fields propagate, as well as in the laboratory frame, through standard quantum field theory calculations. Effects of optical dispersion are also taken into account, and are shown to provide a limited energy bandwidth for the emission of Hawking radiation.

  • Spacetime geometries and light trapping in travelling Refractive Index Perturbations
    New Journal of Physics, 2010
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, V. G. Sala, D. Faccio
    Abstract:

    In the framework of transformation optics, we show that the propagation of a locally superluminal Refractive Index Perturbation (RIP) in a Kerr medium can be described, in the eikonal approximation, by means of a stationary metric, which we prove to be of Gordon type. Under suitable hypotheses on the RIP, we obtain a stationary but not static metric, which is characterized by an ergosphere and by a peculiar behaviour of the geodesics, which are studied numerically, also accounting for material dispersion. Finally, the equation to be satisfied by an event horizon is also displayed and briefly discussed.

  • Quantum radiation from superluminal Refractive-Index Perturbations.
    Physical review letters, 2010
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, V. G. Sala, Daniele Faccio
    Abstract:

    We analyze in detail photon production induced by a superluminal Refractive-Index Perturbation in realistic experimental operating conditions. The interaction between the Refractive-Index Perturbation and the quantum vacuum fluctuations of the electromagnetic field leads to the production of photon pairs.

  • Analogue Gravity and ultrashort laser pulse filamentation
    EPL (Europhysics Letters), 2010
    Co-Authors: Daniele Faccio, Sergio L. Cacciatori, Vittorio Gorini, V. G. Sala, Alessandro Averchi, A. Lotti, Miroslav Kolesik, Jerome V. Moloney
    Abstract:

    Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a moving Refractive Index Perturbation which modifies the space-time geometry as seen by co-propagating light rays. We study the analogue geometry induced by the filament and show that one of the most evident features of filamentation, namely conical emission, may be precisely reconstructed from the geodesics. We highlight the existence of favorable conditions for the study of analogue black hole kinematics and Hawking type radiation.

Francesco Belgiorno - One of the best experts on this subject based on the ideXlab platform.

  • Perturbative photon production in a dispersive medium
    The European Physical Journal D, 2014
    Co-Authors: Francesco Belgiorno, Sergio Luigi Cacciatori, Francesco Dalla Piazza
    Abstract:

    We investigate photon pair-creation in a dispersive dielectric medium induced by the presence of a spacetime varying dielectric constant. Our aim is to examine the possibility to observe new phenomena of pair creation induced by travelling dielectric Perturbations e.g. created by laser pulses by means of the Kerr effect. In this perspective, we adopt a semi-phenomenological version of the Hopfield model in which a space-time dependent dielectric susceptibility appears. We focus our attention on Perturbation theory, and provide general formulas for the photon production induced by a local but arbitrarily spacetime dependent Refractive Index Perturbation. As an example, we further explore the case of a uniformly travelling Perturbation, and provide examples of purely time-dependent Perturbations.

  • Experimental evidence of analogue Hawking radiation from ultrashort laser pulse filaments
    New Journal of Physics, 2011
    Co-Authors: E. Rubino, Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, V. G. Sala, Miroslav Kolesik, Matteo Clerici, Daniele Faccio
    Abstract:

    Curved space–times and, in particular, event horizons of astrophysical black holes are expected to excite the quantum vacuum and give rise to an emission of quanta known as Hawking radiation. Remarkably, many physical systems may be considered analogous to black holes and as such hold promise for the detection of Hawking radiation. In particular, recent progress in the field of transformation optics, i.e. the description of optical systems in terms of curved space–time geometries, has led to a detailed description of methods for generating, via superluminal dielectrics, a blocking horizon for photons. Our measurements highlight the emission of photons from a moving Refractive Index Perturbation induced by a laser pulse that is in quantitative agreement with the Hawking model. This opens an intriguing and readily accessible observation window into quantum field theory in curved space–time geometries.

  • Dielectric black holes induced by a Refractive Index Perturbation and the Hawking effect
    Physical Review D, 2011
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, D. Faccio
    Abstract:

    We consider a 4D model for photon production induced by a Refractive Index Perturbation in a dielectric medium. We show that, in this model, we can infer the presence of a Hawking type effect. This prediction shows up both in the analogue Hawking framework, which is implemented in the pulse frame and relies on the peculiar properties of the effective geometry in which quantum fields propagate, as well as in the laboratory frame, through standard quantum field theory calculations. Effects of optical dispersion are also taken into account, and are shown to provide a limited energy bandwidth for the emission of Hawking radiation.

  • Spacetime geometries and light trapping in travelling Refractive Index Perturbations
    New Journal of Physics, 2010
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, Luca Rizzi, Vittorio Gorini, V. G. Sala, D. Faccio
    Abstract:

    In the framework of transformation optics, we show that the propagation of a locally superluminal Refractive Index Perturbation (RIP) in a Kerr medium can be described, in the eikonal approximation, by means of a stationary metric, which we prove to be of Gordon type. Under suitable hypotheses on the RIP, we obtain a stationary but not static metric, which is characterized by an ergosphere and by a peculiar behaviour of the geodesics, which are studied numerically, also accounting for material dispersion. Finally, the equation to be satisfied by an event horizon is also displayed and briefly discussed.

  • Quantum radiation from superluminal Refractive-Index Perturbations.
    Physical review letters, 2010
    Co-Authors: Francesco Belgiorno, Sergio L. Cacciatori, Giovanni Ortenzi, V. G. Sala, Daniele Faccio
    Abstract:

    We analyze in detail photon production induced by a superluminal Refractive-Index Perturbation in realistic experimental operating conditions. The interaction between the Refractive-Index Perturbation and the quantum vacuum fluctuations of the electromagnetic field leads to the production of photon pairs.