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A. D. R. Phelps - One of the best experts on this subject based on the ideXlab platform.

  • Metallic Periodic Surface Lattice Enhanced High-Power MM-wave Sources
    2018 43rd International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2018
    Co-Authors: A. J. Maclachlan, A. W. Cross, H. Yin, L. Zhang, C.r. Robertson, K. Ronald, A. D. R. Phelps
    Abstract:

    The design and construction of metallic Periodic Surface Lattices (PSLs) to enable oversized cylindrical interaction volumes to be excited efficiently by annular electron beams is presented. Construction methods include metallic electrodeposition and “additive manufacturing”, or “3D printing”.

  • Millimeter-wave Periodic Surface lattices for mode control in vacuum electronic sources
    2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, A. D. R. Phelps
    Abstract:

    Periodic Surface lattice (PSL) structures of planar geometry have been designed, constructed and measured. The motivation is to study the evolution of electromagnetic fields stimulated by PSLs to improve mode control in overmoded structures in high power electron beam driven THz vacuum electronic sources. The results of studies of the planar structures are presented. Prior to the experimental studies numerical simulations have been carried out and results are compared with experimental measurements. It is demonstrated that volume and Surface fields can couple so as to form a cavity eigenmode, which has the potential to be selectively and efficiently excited.

  • Cherenkov maser experiments based on a 2D Periodic Surface Lattice
    2015 IEEE International Conference on Plasma Sciences (ICOPS), 2015
    Co-Authors: A. R. Phipps, A. J. Maclachlan, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, C. G. Whyte, A. D. R. Phelps
    Abstract:

    Numerical finite difference time domain and Particle-In-Cell simulations have demonstrated an electron wave interaction in a Cherenkov maser utilizing a cylindrical two-dimensional (2D) Periodic Surface Lattice (PSL) as a mode selective cavity [1-8]. Optimization of this structure's physical properties resulted in the design of a cavity with 16 longitudinal periods of 1.6 mm length, 7 azimuthal variations and an unperturbed inner radius of 4 mm. In numerical simulations this design produces an output power of 300 kW with 10 % efficiency at a frequency of 103.6 GHz. A proof of principle experiment demonstrating electron beam interaction with a wave formed when the volume field and Surface field are coupled in an oversized 2D PSL cavity will be presented. The application of PSLs has the potential to deliver high average power, efficient, compact electromagnetic wave sources in the challenging THz frequency range.

  • Periodic Surface lattice modelling and experiments
    2015 8th UK Europe China Millimeter Waves and THz Technology Workshop (UCMMT), 2015
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, A. D. R. Phelps
    Abstract:

    Theoretical and modelling studies of Periodic Surface lattice (PSL) structures have been complemented by experiments. A cavity eigenmode can be formed, as a result of volume and Surface wave coupling under certain conditions. The formation of such eigenmodes is relevant to the realization of high-power mm-wave and THz coherent sources.

  • Planar Periodic Surface lattices for use in millimeter-wave sources
    2014 39th International Conference on Infrared Millimeter and Terahertz waves (IRMMW-THz), 2014
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, I. V. Konoplev, A. D. R. Phelps, A. W. Cross
    Abstract:

    Structures based on a Periodic Surface lattice (PSL) of planar geometry have been studied. It is shown that volume and Surface fields can couple to form a cavity eigenmode, demonstrating the potential for novel mm-wave sources when combined in appropriate configurations with an electron beam.

A. J. Maclachlan - One of the best experts on this subject based on the ideXlab platform.

  • Metallic Periodic Surface Lattice Enhanced High-Power MM-wave Sources
    2018 43rd International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2018
    Co-Authors: A. J. Maclachlan, A. W. Cross, H. Yin, L. Zhang, C.r. Robertson, K. Ronald, A. D. R. Phelps
    Abstract:

    The design and construction of metallic Periodic Surface Lattices (PSLs) to enable oversized cylindrical interaction volumes to be excited efficiently by annular electron beams is presented. Construction methods include metallic electrodeposition and “additive manufacturing”, or “3D printing”.

  • Millimeter-wave Periodic Surface lattices for mode control in vacuum electronic sources
    2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, A. D. R. Phelps
    Abstract:

    Periodic Surface lattice (PSL) structures of planar geometry have been designed, constructed and measured. The motivation is to study the evolution of electromagnetic fields stimulated by PSLs to improve mode control in overmoded structures in high power electron beam driven THz vacuum electronic sources. The results of studies of the planar structures are presented. Prior to the experimental studies numerical simulations have been carried out and results are compared with experimental measurements. It is demonstrated that volume and Surface fields can couple so as to form a cavity eigenmode, which has the potential to be selectively and efficiently excited.

  • Cherenkov maser experiments based on a 2D Periodic Surface Lattice
    2015 IEEE International Conference on Plasma Sciences (ICOPS), 2015
    Co-Authors: A. R. Phipps, A. J. Maclachlan, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, C. G. Whyte, A. D. R. Phelps
    Abstract:

    Numerical finite difference time domain and Particle-In-Cell simulations have demonstrated an electron wave interaction in a Cherenkov maser utilizing a cylindrical two-dimensional (2D) Periodic Surface Lattice (PSL) as a mode selective cavity [1-8]. Optimization of this structure's physical properties resulted in the design of a cavity with 16 longitudinal periods of 1.6 mm length, 7 azimuthal variations and an unperturbed inner radius of 4 mm. In numerical simulations this design produces an output power of 300 kW with 10 % efficiency at a frequency of 103.6 GHz. A proof of principle experiment demonstrating electron beam interaction with a wave formed when the volume field and Surface field are coupled in an oversized 2D PSL cavity will be presented. The application of PSLs has the potential to deliver high average power, efficient, compact electromagnetic wave sources in the challenging THz frequency range.

  • Periodic Surface lattice modelling and experiments
    2015 8th UK Europe China Millimeter Waves and THz Technology Workshop (UCMMT), 2015
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, A. D. R. Phelps
    Abstract:

    Theoretical and modelling studies of Periodic Surface lattice (PSL) structures have been complemented by experiments. A cavity eigenmode can be formed, as a result of volume and Surface wave coupling under certain conditions. The formation of such eigenmodes is relevant to the realization of high-power mm-wave and THz coherent sources.

  • Planar Periodic Surface lattices for use in millimeter-wave sources
    2014 39th International Conference on Infrared Millimeter and Terahertz waves (IRMMW-THz), 2014
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, I. V. Konoplev, A. D. R. Phelps, A. W. Cross
    Abstract:

    Structures based on a Periodic Surface lattice (PSL) of planar geometry have been studied. It is shown that volume and Surface fields can couple to form a cavity eigenmode, demonstrating the potential for novel mm-wave sources when combined in appropriate configurations with an electron beam.

Jorg Kruger - One of the best experts on this subject based on the ideXlab platform.

  • Laser-Induced Periodic Surface Structures— A Scientific Evergreen
    IEEE Journal of Selected Topics in Quantum Electronics, 2017
    Co-Authors: Jörn Bonse, Sandra Höhm, Sabrina V. Kirner, Arkadi Rosenfeld, Jorg Kruger
    Abstract:

    Laser-induced Periodic Surface structures (LIPSS, ripples) are a universal phenomenon and can be generated on almost any material upon irradiation with linearly polarized radiation. With the availability of ultrashort laser pulses, LIPSS have gained an increasing attraction during the past decade, since these structures can be generated in a simple single-step process, which allows a Surface nanostructuring for tailoring optical, mechanical, and chemical Surface properties. In this study, the current state in the field of LIPSS is reviewed. Their formation mechanisms are analyzed in ultrafast time-resolved scattering, diffraction, and polarization constrained double-pulse experiments. These experiments allow us to address the question whether the LIPSS are seeded via ultrafast energy deposition mechanisms acting during the absorption of optical radiation or via self-organization after the irradiation process. Relevant control parameters of LIPSS are identified, and technological applications featuring Surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.

  • femtosecond diffraction dynamics of laser induced Periodic Surface structures on fused silica
    Applied Physics Letters, 2013
    Co-Authors: S Hohm, Jorg Kruger, A Rosenfeld, J Bonse
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a transillumination femtosecond time-resolved (0.1 ps-1 ns) pump-probe diffraction approach. This allows to reveal the generation dynamics of near-wavelength-sized LIPSS showing a transient diffraction at specific spatial frequencies even before a corresponding permanent Surface relief was observed. The results confirm that the ultrafast energy deposition to the materials Surface plays a key role and triggers subsequent physical mechanisms such as carrier scattering into self-trapped excitons.

  • femtosecond laser induced Periodic Surface structures
    Journal of Laser Applications, 2012
    Co-Authors: J Bonse, Jorg Kruger, S Hohm, A Rosenfeld
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∼ 30–150 fs, λ ∼ 800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (∼λ/10) can be generated. For semiconductors, the impact of transient changes of the optical properties to the LIPSS periods is analyzed theoretically and experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated experimentally using (multiple) double-fs-laser-pulse irradiation sequences. A characteristic decrease of the LIPSS periods is observed for double-pulse delays of less than 2 ps.

  • femtosecond laser induced Periodic Surface structures on silica
    Journal of Applied Physics, 2012
    Co-Authors: S Hohm, Jorg Kruger, A Rosenfeld, J Bonse
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) on two different silica polymorphs (single-crystalline synthetic quartz and commercial fused silica glass) upon irradiation in air with multiple linearly polarized single- and double-fs-laser pulse sequences (τ = 150 fs pulse duration, λ = 800 nm center wavelength, temporal pulse separation Δt < 40 ps) is studied experimentally and theoretically. Two distinct types of fs-LIPSS [so-called low-spatial-frequency LIPSS (LSFL) and high-spatial-frequency LIPSS (HSFL)] with different spatial periods and orientations were identified. Their appearance was characterized with respect to the experimental parameters peak laser fluence and number of laser pulses per spot. Additionally, the “dynamics” of the LIPSS formation was addressed in complementary double-fs-pulse experiments with varying delays, revealing a characteristic change of the LSFL periods. The experimental results are interpreted on the basis of a Sipe-Drude model considering the carrier...

J Bonse - One of the best experts on this subject based on the ideXlab platform.

  • femtosecond diffraction dynamics of laser induced Periodic Surface structures on fused silica
    Applied Physics Letters, 2013
    Co-Authors: S Hohm, Jorg Kruger, A Rosenfeld, J Bonse
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a transillumination femtosecond time-resolved (0.1 ps-1 ns) pump-probe diffraction approach. This allows to reveal the generation dynamics of near-wavelength-sized LIPSS showing a transient diffraction at specific spatial frequencies even before a corresponding permanent Surface relief was observed. The results confirm that the ultrafast energy deposition to the materials Surface plays a key role and triggers subsequent physical mechanisms such as carrier scattering into self-trapped excitons.

  • femtosecond laser induced Periodic Surface structures
    Journal of Laser Applications, 2012
    Co-Authors: J Bonse, Jorg Kruger, S Hohm, A Rosenfeld
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) in different materials (metals, semiconductors, and dielectrics) upon irradiation with linearly polarized fs-laser pulses (τ ∼ 30–150 fs, λ ∼ 800 nm) in air environment is studied experimentally and theoretically. In metals, predominantly low-spatial-frequency-LIPSS with periods close to the laser wavelength λ are observed perpendicular to the polarization. Under specific irradiation conditions, high-spatial-frequency-LIPSS with sub-100-nm spatial periods (∼λ/10) can be generated. For semiconductors, the impact of transient changes of the optical properties to the LIPSS periods is analyzed theoretically and experimentally. In dielectrics, the importance of transient excitation stages in the LIPSS formation is demonstrated experimentally using (multiple) double-fs-laser-pulse irradiation sequences. A characteristic decrease of the LIPSS periods is observed for double-pulse delays of less than 2 ps.

  • femtosecond laser induced Periodic Surface structures on silica
    Journal of Applied Physics, 2012
    Co-Authors: S Hohm, Jorg Kruger, A Rosenfeld, J Bonse
    Abstract:

    The formation of laser-induced Periodic Surface structures (LIPSS) on two different silica polymorphs (single-crystalline synthetic quartz and commercial fused silica glass) upon irradiation in air with multiple linearly polarized single- and double-fs-laser pulse sequences (τ = 150 fs pulse duration, λ = 800 nm center wavelength, temporal pulse separation Δt < 40 ps) is studied experimentally and theoretically. Two distinct types of fs-LIPSS [so-called low-spatial-frequency LIPSS (LSFL) and high-spatial-frequency LIPSS (HSFL)] with different spatial periods and orientations were identified. Their appearance was characterized with respect to the experimental parameters peak laser fluence and number of laser pulses per spot. Additionally, the “dynamics” of the LIPSS formation was addressed in complementary double-fs-pulse experiments with varying delays, revealing a characteristic change of the LSFL periods. The experimental results are interpreted on the basis of a Sipe-Drude model considering the carrier...

A. W. Cross - One of the best experts on this subject based on the ideXlab platform.

  • Metallic Periodic Surface Lattice Enhanced High-Power MM-wave Sources
    2018 43rd International Conference on Infrared Millimeter and Terahertz Waves (IRMMW-THz), 2018
    Co-Authors: A. J. Maclachlan, A. W. Cross, H. Yin, L. Zhang, C.r. Robertson, K. Ronald, A. D. R. Phelps
    Abstract:

    The design and construction of metallic Periodic Surface Lattices (PSLs) to enable oversized cylindrical interaction volumes to be excited efficiently by annular electron beams is presented. Construction methods include metallic electrodeposition and “additive manufacturing”, or “3D printing”.

  • Millimeter-wave Periodic Surface lattices for mode control in vacuum electronic sources
    2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, A. D. R. Phelps
    Abstract:

    Periodic Surface lattice (PSL) structures of planar geometry have been designed, constructed and measured. The motivation is to study the evolution of electromagnetic fields stimulated by PSLs to improve mode control in overmoded structures in high power electron beam driven THz vacuum electronic sources. The results of studies of the planar structures are presented. Prior to the experimental studies numerical simulations have been carried out and results are compared with experimental measurements. It is demonstrated that volume and Surface fields can couple so as to form a cavity eigenmode, which has the potential to be selectively and efficiently excited.

  • Cherenkov maser experiments based on a 2D Periodic Surface Lattice
    2015 IEEE International Conference on Plasma Sciences (ICOPS), 2015
    Co-Authors: A. R. Phipps, A. J. Maclachlan, C. W. Robertson, A. W. Cross, I. V. Konoplev, K. Ronald, C. G. Whyte, A. D. R. Phelps
    Abstract:

    Numerical finite difference time domain and Particle-In-Cell simulations have demonstrated an electron wave interaction in a Cherenkov maser utilizing a cylindrical two-dimensional (2D) Periodic Surface Lattice (PSL) as a mode selective cavity [1-8]. Optimization of this structure's physical properties resulted in the design of a cavity with 16 longitudinal periods of 1.6 mm length, 7 azimuthal variations and an unperturbed inner radius of 4 mm. In numerical simulations this design produces an output power of 300 kW with 10 % efficiency at a frequency of 103.6 GHz. A proof of principle experiment demonstrating electron beam interaction with a wave formed when the volume field and Surface field are coupled in an oversized 2D PSL cavity will be presented. The application of PSLs has the potential to deliver high average power, efficient, compact electromagnetic wave sources in the challenging THz frequency range.

  • Periodic Surface lattice modelling and experiments
    2015 8th UK Europe China Millimeter Waves and THz Technology Workshop (UCMMT), 2015
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, A. W. Cross, I. V. Konoplev, A. D. R. Phelps
    Abstract:

    Theoretical and modelling studies of Periodic Surface lattice (PSL) structures have been complemented by experiments. A cavity eigenmode can be formed, as a result of volume and Surface wave coupling under certain conditions. The formation of such eigenmodes is relevant to the realization of high-power mm-wave and THz coherent sources.

  • Planar Periodic Surface lattices for use in millimeter-wave sources
    2014 39th International Conference on Infrared Millimeter and Terahertz waves (IRMMW-THz), 2014
    Co-Authors: A. J. Maclachlan, A. R. Phipps, C. W. Robertson, I. V. Konoplev, A. D. R. Phelps, A. W. Cross
    Abstract:

    Structures based on a Periodic Surface lattice (PSL) of planar geometry have been studied. It is shown that volume and Surface fields can couple to form a cavity eigenmode, demonstrating the potential for novel mm-wave sources when combined in appropriate configurations with an electron beam.