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52. Exploring the polarization dependence of supercontinuum generation in silicon-nitride waveguides

Author

van Zon, Robert, Bastiaens, H.M.J., Lüpken, Niklas M., Fallnich, C., Boller, K.-J., and Laser Physics & Nonlinear Optics

Abstract

The broad coherent spectra obtained by supercontinuum generation (SCG) are of significant importance for applications in, e.g., spectroscopy and precision metrology. Of particular interest is SCG using integrated optical waveguides fabricated from stoichiometric silicon nitride (Si3N4), which has provided the broadest supercontinuum, so far, on a chip [1]. Although SCG in silicon-nitride waveguides is extensively studied, it is limited to input beams polarized to excite either the fundamental (quasi) TE- or TM-mode of these waveguides. Here, we explore the dependence of SCG in silicon-nitride waveguides on varying polarization directions of the pump and varying birefringence of the waveguide cross-section, both experimentally and numerically. Applying pump light polarized to excite the TE and TM modes simultaneously, we find that the generated SC spectrum becomes much broader than the spectra from the separately excited TE- and TM-modes. [1] J. P. Epping et al., "On-chip visible-to-infrared supercontinuum generation with more than 495 THz spectral bandwidth", Opt. Express 23, 19596 (2015).

Published
2019

53. Applying the interaction picture to model Kerr frequency comb generation

Author

Schuttrups, Bas, van der Slot, P.J.M., Geurts, Bernardus J., Boller, K.-J., Multiscale Modeling and Simulation, and Laser Physics & Nonlinear Optics

Subjects
Physics::Optics
Abstract

The Lugiato-Lefever equation (LLE) is often used to model Kerr frequency comb generation and various mathematical techniques have been used to solve this equation. Typically, these techniques use a split-step method that is often supplemented with additional optimization steps. An alternative and promising method is the '4th-order Runge-Kutta method in the Interaction Picture' (RK4IP) [1], which has been successfully used to model supercontinuum generation and various phenomena in Bose-Einstein condensates. The algorithm is memory efficient and provides fourth-order global accuracy. We use the RK4IP algorithm as an efficient and robust solver for the LLE. We discuss the implementation and present first modelling results of Kerr frequency comb generation in silicon nitride rings. [1] B. M. Caradoc-Davies, “Vortex dynamics in Bose–Einstein condensates,” Ph.D. dissertation, Univ. Otago, Dunedin, New Zealand, 2000

Published
2019

54. Kerr frequency comb generation in silicon nitride micro-ring resonators

Author

Klaver, Y., Bastiaens, H.M.J., Boller, K.-J., and Laser Physics & Nonlinear Optics

Subjects
Physics::Optics
Abstract

Frequency comb generation in waveguide micro-ring resonators on a chip enables to realize compact, portable, and robust coherent sources with a large bandwidth span, finding use in various applications including precision spectroscopy, frequency metrology, and optical clocks. Essential properties for the resonator are a high quality factor and small mode volume to yield a low threshold, a dispersion engineered cross section to fulfill phase matching conditions, and appropriate optical laser excitation. We demonstrate Kerr comb generation in micro-ring resonators fabricated from stoichiometric silicon nitride (Si3N4) with various ring diameters and coupling parameters [1]. We report on the dependence of the threshold and the generated comb spectrum on the quality factor of the resonator and pump power, respectively. [1] C.G.H. Roeloffzen et al., "Low-loss Si3N4 TriPleX optical waveguides: technology and applications overview", IEEE J. Sel.Top. Quant. Electron. 24, 4400321 (2018).

Published
2019

56. Revisiting argon cluster formation in a planar gas jet for high-intensity laser matter interaction.

Author

Tao, Y., Hagmeijer, R., van der Weide, E. T. A., Bastiaens, H. M. J., and Boller, K.-J.

Subjects
INDUSTRIAL lasers, ARGON spectra, RAYLEIGH scattering, MICROCLUSTERS, THERMODYNAMIC equilibrium
Abstract

We determine the size of argon clusters generated with a planar nozzle, based on the optical measurements in conjunction with theoretical modelling. Using a quasi-one dimensional model for the moments of the cluster size distribution, we determine the influence of critical physical assumptions. These refer to the surface tension depending on the presence of thermal equilibrium, the mass density of clusters, and different methods to model the growth rate of the cluster radius. We show that, despite strong variation in the predicted cluster size, ⟨N⟩, the liquid mass ratio, g, can be determined with high trustworthiness, because g is predicted as being almost independent of the specific model assumptions. Exploiting this observation, we use the calculated value for g to retrieve the cluster size from optical measurements, i.e., calibrated Rayleigh scattering and interferometry. Based on the measurements of the cluster size vs. the nozzle stagnation pressure, we provide a new power law for the prediction of the cluster size in experiments with higher values of the Hagena parameter (Γ*>104). This range is of relevance for experiments on high-intensity laser matter interactions. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
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59. Prospects for fundamental physics with LISA

Author

Theoretical Physics, Sub NMR Spectroscopy, LS Immunologie, Afd Subatomic Physics (SAP), Afd OT Educatie en pedagogiek, Sub General Pharmaceutics, Sub RvdM overig, Sub String Theory Cosmology and ElemPart, Dep Natuurkunde, Sub Inorganic Chemistry and Catalysis, LS Wijsgerige Ethiek, Section Geography and Education, Barausse, Enrico, Berti, Emanuele, Hertog, Thomas, Hughes, Scott A., Jetzer, Philippe, Pani, Paolo, Sotiriou, Thomas P., Tamanini, Nicola, Witek, Helvi, Yagi, Kent, Yunes, Nicolas, Abdelsalhin, T., Achucarro, A., van Aelst, K., Afshordi, N., Akcay, S., Annulli, L., Arun, K. G., Ayuso, I., Baibhav, V., Baker, T., Bantilan, H., Barreiro, T., Barrera-Hinojosa, C., Bartolo, N., Baumann, D., Belgacem, E., Bellini, E., Bellomo, N., Ben-Dayan, I., Bena, I., Benkel, R., Bergshoefs, E., Bernard, L., Bernuzzi, S., Bertacca, D., Besancon, M., Beutler, F., Beyer, F., Bhagwat, S., Bicak, J., Biondini, S., Bize, S., Blas, D., Boehmer, C., Boller, K., Bonga, B., Bonvin, C., Bosso, P., Bozzola, G., Brax, P., Breitbach, M., Brito, R., Bruni, M., Bruegmann, B., Bulten, H., Buonanno, A., Burko, L. M., Burrage, C., Cabral, F., Calcagni, G., Caprini, C., Cardenas-Avendano, A., Celoria, M., Chatziioannou, K., Chernoff, D., Clough, K., Coates, A., Comelli, D., Compere, G., Croon, D., Cruces, D., Cusin, G., Dalang, C., Danielsson, U., Das, S., Datta, S., de Boer, J., De Luca, V., De Rham, C., Desjacques, V., Destounis, K., Filippo, F. Di, Dima, A., Dimastrogiovanni, E., Dolan, S., Doneva, D., Duque, F., Durrer, R., East, W., Easther, R., Elley, M., Ellis, J. R., Emparan, R., Ezquiaga, J. M., Fairbairn, M., Fairhurst, S., Farmer, H. F., Fasiello, M. R., Ferrari, V., Ferreira, P. G., Ficarra, G., Figueras, P., Fisenko, S., Foffa, S., Franchini, N., Franciolini, G., Fransen, K., Frauendiener, J., Frusciante, N., Fujita, R., Gair, J., Ganz, A., Garcia, P., Garcia-Bellido, J., Garriga, J., Geiger, R., Geng, C., Gergely, L. a., Germani, C., Gerosa, D., Giddings, S. B., Gourgoulhon, E., Grandclement, P., Graziani, L., Gualtieri, L., Haggard, D., Haino, S., Halburd, R., Han, W. -B., Hawken, A. J., Hees, A., Heng, I. S., Hennig, J., Herdeiro, C., Hervik, S., Holten, J. v., Hoyle, C. D., Hu, Y., Hull, M., Ikeda, T., Isi, M., Jenkins, A., Julie, F., Kajfasz, E., Kalaghatgi, C., Kaloper, N., Kamionkowski, M., Karas, V., Kastha, S., Keresztes, Z., Kidder, L., Kimpson, T., Klein, A., Klioner, S., Kokkotas, K., Kolesova, H., Kolkowitz, S., Kopp, J., Koyama, K., Krishnendu, N. V., Kroon, J. A. V., Kunz, M., Lahav, O., Landragin, A., Lang, R. N., Poncin-Lafitte, C. Le, Lemos, J., Li, B., Liberati, S., Liguori, M., Lin, F., Liu, G., Lobo, F. S. N., Loll, R., Lombriser, L., Lovelace, G., Macedo, R. P., Madge, E., Maggio, E., Maggiore, M., Marassi, S., Marcoccia, P., Markakis, C., Martens, W., Martinovic, K., Martins, C. J. A. P., Maselli, A., Mastrogiovanni, S., Matarrese, S., Matas, A., Mavromatos, N. E., Mazumdar, A., Meerburg, P. D., Megias, E., Miller, J., Mimoso, J. P., Mittnacht, L., Montero, M. M., Moore, B., Martin-Moruno, P., Musco, I., Nakano, H., Nampalliwar, S., Nardini, G., Nielsen, A., Novak, J., Nunes, N. J., Okounkova, M., Oliveri, R., Oppizzi, F., Orlando, G., Oshita, N., Pappas, G., Paschalidis, V., Peiris, H., Peloso, M., Perkins, S., Pettorino, V., Pikovski, I., Pilo, L., Podolsky, J., Pontzen, A., Prabhat, S., Pratten, G., Prokopec, T., Prouza, M., Qi, H., Raccanelli, A., Rajantie, A., Randall, L., Raposo, G., Raymond, V., Renaux-Petel, S., Ricciardone, A., Riotto, A., Robson, T., Roest, D., Rollo, R., Rosofsky, S., Ruan, J. J., Rubiera-Garcia, D., Ruiz, M., Rusu, M., Sabatie, F., Sago, N., Sakellariadou, M., Saltas, I. D., Sberna, L., Sathyaprakash, B., Scheel, M., Schmidt, P., Schutz, B., Schwaller, P., Shao, L., Shapiro, S. L., Shoemaker, D., Silva, A. d., Simpson, C., Sopuerta, C. F., Spallicci, A., Stefanek, B. A., Stein, L., Stergioulas, N., Stott, M., Sutton, P., Svarc, R., Tagoshi, H., Tahamtan, T., Takeda, H., Tanaka, T., Tantilian, G., Tasinato, G., Tattersall, O., Teukolsky, S., Tiec, A. L., Theureau, G., Trodden, M., Tolley, A., Toubiana, A., Traykova, D., Tsokaros, A., Unal, C., Unnikrishnan, C. S., Vagenas, E. C., Valageas, P., Vallisneri, M., Brand, J. Van den, Broeck, C. Van den, de Meent, M. van, Vanhove, P., Varma, V., Veitch, J., Vercnocke, B., Verde, L., Vernieri, D., Vernizzi, F., Vicente, R., Vidotto, F., Visser, M., Vlah, Z., Vretinaris, S., Voelkel, S., Wang, Q., Wang, Yu-Tong, Werner, M. C., Westernacher, J., Weygaert, R. v. d., Wiltshire, D., Wiseman, T., Wolf, P., Wu, K., Yamada, K., Yang, H., Yi, L., Yue, X., Yvon, D., Zilhao, M., Zimmerman, A., Zumalacarregui, M., Theoretical Physics, Sub NMR Spectroscopy, LS Immunologie, Afd Subatomic Physics (SAP), Afd OT Educatie en pedagogiek, Sub General Pharmaceutics, Sub RvdM overig, Sub String Theory Cosmology and ElemPart, Dep Natuurkunde, Sub Inorganic Chemistry and Catalysis, LS Wijsgerige Ethiek, Section Geography and Education, Barausse, Enrico, Berti, Emanuele, Hertog, Thomas, Hughes, Scott A., Jetzer, Philippe, Pani, Paolo, Sotiriou, Thomas P., Tamanini, Nicola, Witek, Helvi, Yagi, Kent, Yunes, Nicolas, Abdelsalhin, T., Achucarro, A., van Aelst, K., Afshordi, N., Akcay, S., Annulli, L., Arun, K. G., Ayuso, I., Baibhav, V., Baker, T., Bantilan, H., Barreiro, T., Barrera-Hinojosa, C., Bartolo, N., Baumann, D., Belgacem, E., Bellini, E., Bellomo, N., Ben-Dayan, I., Bena, I., Benkel, R., Bergshoefs, E., Bernard, L., Bernuzzi, S., Bertacca, D., Besancon, M., Beutler, F., Beyer, F., Bhagwat, S., Bicak, J., Biondini, S., Bize, S., Blas, D., Boehmer, C., Boller, K., Bonga, B., Bonvin, C., Bosso, P., Bozzola, G., Brax, P., Breitbach, M., Brito, R., Bruni, M., Bruegmann, B., Bulten, H., Buonanno, A., Burko, L. M., Burrage, C., Cabral, F., Calcagni, G., Caprini, C., Cardenas-Avendano, A., Celoria, M., Chatziioannou, K., Chernoff, D., Clough, K., Coates, A., Comelli, D., Compere, G., Croon, D., Cruces, D., Cusin, G., Dalang, C., Danielsson, U., Das, S., Datta, S., de Boer, J., De Luca, V., De Rham, C., Desjacques, V., Destounis, K., Filippo, F. Di, Dima, A., Dimastrogiovanni, E., Dolan, S., Doneva, D., Duque, F., Durrer, R., East, W., Easther, R., Elley, M., Ellis, J. R., Emparan, R., Ezquiaga, J. M., Fairbairn, M., Fairhurst, S., Farmer, H. F., Fasiello, M. R., Ferrari, V., Ferreira, P. G., Ficarra, G., Figueras, P., Fisenko, S., Foffa, S., Franchini, N., Franciolini, G., Fransen, K., Frauendiener, J., Frusciante, N., Fujita, R., Gair, J., Ganz, A., Garcia, P., Garcia-Bellido, J., Garriga, J., Geiger, R., Geng, C., Gergely, L. a., Germani, C., Gerosa, D., Giddings, S. B., Gourgoulhon, E., Grandclement, P., Graziani, L., Gualtieri, L., Haggard, D., Haino, S., Halburd, R., Han, W. -B., Hawken, A. J., Hees, A., Heng, I. S., Hennig, J., Herdeiro, C., Hervik, S., Holten, J. v., Hoyle, C. D., Hu, Y., Hull, M., Ikeda, T., Isi, M., Jenkins, A., Julie, F., Kajfasz, E., Kalaghatgi, C., Kaloper, N., Kamionkowski, M., Karas, V., Kastha, S., Keresztes, Z., Kidder, L., Kimpson, T., Klein, A., Klioner, S., Kokkotas, K., Kolesova, H., Kolkowitz, S., Kopp, J., Koyama, K., Krishnendu, N. V., Kroon, J. A. V., Kunz, M., Lahav, O., Landragin, A., Lang, R. N., Poncin-Lafitte, C. Le, Lemos, J., Li, B., Liberati, S., Liguori, M., Lin, F., Liu, G., Lobo, F. S. N., Loll, R., Lombriser, L., Lovelace, G., Macedo, R. P., Madge, E., Maggio, E., Maggiore, M., Marassi, S., Marcoccia, P., Markakis, C., Martens, W., Martinovic, K., Martins, C. J. A. P., Maselli, A., Mastrogiovanni, S., Matarrese, S., Matas, A., Mavromatos, N. E., Mazumdar, A., Meerburg, P. D., Megias, E., Miller, J., Mimoso, J. P., Mittnacht, L., Montero, M. M., Moore, B., Martin-Moruno, P., Musco, I., Nakano, H., Nampalliwar, S., Nardini, G., Nielsen, A., Novak, J., Nunes, N. J., Okounkova, M., Oliveri, R., Oppizzi, F., Orlando, G., Oshita, N., Pappas, G., Paschalidis, V., Peiris, H., Peloso, M., Perkins, S., Pettorino, V., Pikovski, I., Pilo, L., Podolsky, J., Pontzen, A., Prabhat, S., Pratten, G., Prokopec, T., Prouza, M., Qi, H., Raccanelli, A., Rajantie, A., Randall, L., Raposo, G., Raymond, V., Renaux-Petel, S., Ricciardone, A., Riotto, A., Robson, T., Roest, D., Rollo, R., Rosofsky, S., Ruan, J. J., Rubiera-Garcia, D., Ruiz, M., Rusu, M., Sabatie, F., Sago, N., Sakellariadou, M., Saltas, I. D., Sberna, L., Sathyaprakash, B., Scheel, M., Schmidt, P., Schutz, B., Schwaller, P., Shao, L., Shapiro, S. L., Shoemaker, D., Silva, A. d., Simpson, C., Sopuerta, C. F., Spallicci, A., Stefanek, B. A., Stein, L., Stergioulas, N., Stott, M., Sutton, P., Svarc, R., Tagoshi, H., Tahamtan, T., Takeda, H., Tanaka, T., Tantilian, G., Tasinato, G., Tattersall, O., Teukolsky, S., Tiec, A. L., Theureau, G., Trodden, M., Tolley, A., Toubiana, A., Traykova, D., Tsokaros, A., Unal, C., Unnikrishnan, C. S., Vagenas, E. C., Valageas, P., Vallisneri, M., Brand, J. Van den, Broeck, C. Van den, de Meent, M. van, Vanhove, P., Varma, V., Veitch, J., Vercnocke, B., Verde, L., Vernieri, D., Vernizzi, F., Vicente, R., Vidotto, F., Visser, M., Vlah, Z., Vretinaris, S., Voelkel, S., Wang, Q., Wang, Yu-Tong, Werner, M. C., Westernacher, J., Weygaert, R. v. d., Wiltshire, D., Wiseman, T., Wolf, P., Wu, K., Yamada, K., Yang, H., Yi, L., Yue, X., Yvon, D., Zilhao, M., Zimmerman, A., and Zumalacarregui, M.

Published
2020

60. Prospects for fundamental physics with LISA

Author

European Commission, Royal Society (UK), National Aeronautics and Space Administration (US), National Science Foundation (US), Alfred P. Sloan Foundation, Science and Technology Facilities Council (UK), Barausse, Enrico, Berti, E., Hertog, T., Hughes, S.A., Jetzer, P., Pani, Paolo, Sotiriou, T.P., Tamanini, N., Witek, H., Yagi, K., Yunes, N., Abdelsalhin, T., Achucarro, A., Aelst, K. van, Afshordi, N., Akcay, S., Annulli, L., Arun, K. G., Ayuso, I., Baibhav, V., Baker, Tessa, Bantilan, H., Barreiro, Tiago, Barrera-Hinojosa, C., Bartolo, Nicola, Baumann, D., Belgacem, Enis, Bellini, E., Bellomo, Nicola, Ben-Dayan, I., Bena, I., Benkel, R., Bergshoefs, E., Bernard, L., Bernuzzi, S., Bertacca, D., Besancon, M., Beutler, F., Beyer, F., Bhagwat, S., Bicak, J., Biondini, S., Bize, S., Blas, D., Boehmer, C., Boller, K., Bonga, B., Bonvin, Camille, Bosso, P., Calcagni, Gianluca, Cruces, D., Emparan, R., García-Bellido, Juan, Garriga, J., Germani, C., Megias, E., Martín Moruno, Prado, Musco, I., Rubiera-García, D., Sopuerta, Carlos F., Verde, Licia, European Commission, Royal Society (UK), National Aeronautics and Space Administration (US), National Science Foundation (US), Alfred P. Sloan Foundation, Science and Technology Facilities Council (UK), Barausse, Enrico, Berti, E., Hertog, T., Hughes, S.A., Jetzer, P., Pani, Paolo, Sotiriou, T.P., Tamanini, N., Witek, H., Yagi, K., Yunes, N., Abdelsalhin, T., Achucarro, A., Aelst, K. van, Afshordi, N., Akcay, S., Annulli, L., Arun, K. G., Ayuso, I., Baibhav, V., Baker, Tessa, Bantilan, H., Barreiro, Tiago, Barrera-Hinojosa, C., Bartolo, Nicola, Baumann, D., Belgacem, Enis, Bellini, E., Bellomo, Nicola, Ben-Dayan, I., Bena, I., Benkel, R., Bergshoefs, E., Bernard, L., Bernuzzi, S., Bertacca, D., Besancon, M., Beutler, F., Beyer, F., Bhagwat, S., Bicak, J., Biondini, S., Bize, S., Blas, D., Boehmer, C., Boller, K., Bonga, B., Bonvin, Camille, Bosso, P., Calcagni, Gianluca, Cruces, D., Emparan, R., García-Bellido, Juan, Garriga, J., Germani, C., Megias, E., Martín Moruno, Prado, Musco, I., Rubiera-García, D., Sopuerta, Carlos F., and Verde, Licia

Abstract

In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental physics. Given the very broad range of topics that might be relevant to LISA,we present here a sample of what we view as particularly promising fundamental physics directions. We organize these directions through a “science-first” approach that allows us to classify how LISA data can inform theoretical physics in a variety of areas. For each of these theoretical physics classes, we identify the sources that are currently expected to provide the principal contribution to our knowledge, and the areas that need further development. The classification presented here should not be thought of as cast in stone, but rather as a fluid framework that is amenable to change with the flow of new insights in theoretical physics.

Published
2020

65. Enhanced high-order harmonic generation from Argon-clusters

Author

Tao, Yin, Hagmeijer, Rob, Bastiaens, H.M.J., Goh, S.J., van der Slot, P.J.M., Biedron, S., Milton, S., Boller, K.-J., and Laser Physics & Nonlinear Optics

Subjects
Physics::Atomic and Molecular Clusters, Physics::Atomic Physics
Abstract

High-order harmonic generation (HHG) in clusters is of high promise because clusters appear to offer an increased optical nonlinearity. We experimentally investigate HHG from Argon clusters in a supersonic gas jet that can generate monomer-cluster mixtures with varying atomic number density and associated liquid mass fraction, g, and average cluster size. To obtain the single-atom response from atoms within the cluster, we use two models to theoretically obtain both the expected high-order harmonic yield from monomers and g. Our analysis shows an enhanced single-atom response from atoms in clusters of small size (

Published
2017

67. Photoelectric effects in x-ray preionization for excimer laser gases.

Author

Azarov, A. V., Peters, P. J. M., and Boller, K.-J.

Subjects
ELECTRON distribution, EXCIMER lasers, OPTOELECTRONIC devices, IONIZATION (Atomic physics), PHOTOEMISSION
Abstract

We present detailed measurements on the x-ray preionization electron density in a discharge chamber filled with different gases relevant to discharge pumped high-pressure excimer lasers. By comparing experimental results with the theoretical electron densities, we conclude that the observed preionization is inconsistent with the standard picture of direct ionization through x-ray absorption in the gas. We conclude that depending on the gas pressure, type of gas, and the gap length between the discharge electrodes used, x-ray preionization in excimer gases is, to a significant extent or even dominantly, based on a different mechanism. We identify that this mechanism is based on fast photoelectrons emitted by the cathode into the discharge chamber. [ABSTRACT FROM AUTHOR]

Published
2008
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68. Gain of a long-pulse KrCl excimer laser.

Author

Casper, L. C., Bastiaens, H. M. J., Peters, P. J. M., Boller, K.-J., and Hofstra, R. M.

Subjects
LASERS, KRYPTON, EXCIMER lasers, INDUSTRIAL applications of ultraviolet radiation, FLUORESCENCE
Abstract

The net gain is measured for various pump power densities in a discharge-pumped long-pulse KrCl laser (222 nm). For this, a three-electrode laser system is employed, which is operated at high gas pressures of around 3.5 bar with pump power densities of 300-650 kW cm-3. The net gain reaches a maximum of 1.6% cm-1. Using the experimental results, values are calculated for the small-signal gain, the losses, and the saturation intensity. The losses and the saturation intensity are found to increase much stronger with the excitation rate than the small-signal gain. Fluorescence measurements at 222 nm show that the upper laser level depopulates faster when the power density increases. The influence of collisional quenching and the halogen consumption on the laser performance are discussed. [ABSTRACT FROM AUTHOR]

Published
2007
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69. Effect of preionization, fluorine concentration, and current density on the discharge uniformity in F2 excimer laser gas mixtures.

Author

Mathew, D., Bastiaens, H. M. J., Boller, K. J., and Peters, P. J. M.

Subjects
EXCIMER lasers, IONIZATION (Atomic physics), FLUORINE, X-ray bursts, HALOGENS, GLOW discharges
Abstract

The discharge homogeneity in F2-based excimer laser gas mixtures and its dependence on various key parameters, such as the degree of preionization, preionization delay time, F2 concentration and current density, is investigated in a small x-ray preionized discharge chamber. The spatial and temporal evolution of the discharges is monitored by taking photographs of the discharge fluorescence with a fast intensified CCD camera. It is found that a preionization electron density of about 107 cm-3 bar-1 is sufficient to initiate a streamer-free homogeneous discharge in gas mixtures of helium and fluorine with multiatmospheric gas pressure. The accompanying optimum time delay between the application of the x-ray pulse and voltage across the discharge electrodes is determined to be about 20 ns. It is shown that in spite of these optimum initial conditions, a homogeneous glow discharge eventually transforms into an inhomogeneous discharge containing numerous filaments. Our experiments show that the higher the initial F2 concentration, the initial current density or the pump power density, the shorter the time interval over which the discharge stays homogeneous. By a quantitative characterization and defining a detailed measure of the observed discharge inhomogeneity we find that halogen depletion, as suggested from the theory, is responsible for the temporal instability of discharges in such laser gas mixtures, as the experimental results are in good agreement with the theory on the halogen depletion instability mechanism. [ABSTRACT FROM AUTHOR]

Published
2007
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70. Design and simulation of laser wakefield acceleration with external electron bunch injection in front of the laser pulse.

Author

Irman, A., Luttikhof, M. J. H., Khachatryan, A. G., van Goor, F. A., Verschuur, J. W. J., Bastiaens, H. M. J., and Boller, K.-J.

Subjects
PARTICLES (Nuclear physics), SCIENTIFIC experimentation, LASER beams, STATISTICAL hypothesis testing, FREQUENCIES of oscillating systems
Abstract

In this article we present a theoretical investigation on an experimental design of a laser wakefield accelerator in which electron bunches from a photocathode radio frequency linac are injected into a capillary discharge plasma channel just in front of a few tens of terawatt drive laser pulse. The electron bunch, with a kinetic energy of 2.9 MeV and an energy chirp imposed by the linac, is magnetically compressed by a factor of 8 to a duration of 250 fs, and is magnetically focused into the plasma channel where it matches the spot size of the drive laser (≈30 μm). The dynamics of the bunch, starting from the photocathode, through the linac, along the beam transportation line, through the magnetic compressor, and its focusing into the plasma channel are comprehensively simulated with the general particle tracer code. Further, we use our three-dimensional numerical codes to calculate the laser wakefield and to determine and optimize the trapping and acceleration of the injected bunch in the wakefield. We show that, injecting a 5 pC electron bunch of 250 fs duration, the experiment should deliver an electron bunch of approximately 744 MeV energy, with 1.1% relative energy spread, and with an extremely short duration (6 fs), after acceleration in a 5.4 cm long plasma channel. [ABSTRACT FROM AUTHOR]

Published
2007
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71. Phase velocity fluctuations and gain in Cherenkov free-electron lasers.

Author

de la Fuente, I., van der Slot, P. J. M., and Boller, K.-J.

Subjects
CHERENKOV radiation, FREE electron lasers, SPEED of light, WAVEGUIDES, FLUCTUATIONS (Physics)
Abstract

We report on the influence that waveguide-induced fluctuations in the phase velocity of the radiation wave have on the gain of Cherenkov-type free-electron lasers. We theoretically analyze low-gain Cherenkov free-electron lasers with a compact design that require resonator feedback for operation. We find that even small spatial variations of the waveguide parameters along the propagation direction can lead to significant degradation of the gain, and we present typical values for the required degree in waveguide precision that would eliminate such effects. [ABSTRACT FROM AUTHOR]

Published
2006
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73. Narrow-linewidth widely tunable hybrid external cavity laser using Si3N4/SiO2 microring resonators

Author

Zhao, J.L., Oldenbeuving, R.M., Epping, J.P., Hoekman, M., Heideman, R.G., Dekker, R., Fan, Y., Boller, K.-J., Ji, R.Q., Fu, S.M., Zeng, L., Laser Physics & Nonlinear Optics, and MESA+ Institute

Subjects
Electron optics, 2023 OA procedure, Decision support systems, Optimized production technology, Diode lasers
Abstract

We report on the characteristics of a tunable hybrid external cavity laser using silicon nitride microring resonators. A wavelength tuning range covering from 1530nm to 1580nm is demonstrated with a side mode suppression ratio larger than 45dB. Typical linewidth values are 65kHz.

Published
2016

75. Optically switched 56 GBd PAM-4 using a hybrid InP-TriPleX integrated tunable laser based on silicon nitride micro-ring resonators

Author

Browning, C., primary, Ruffini, M., additional, Lin, Y., additional, Timens, R. B., additional, Geuzebroek, D. H., additional, Roeloffzen, C. G. H., additional, Geskus, D., additional, Oldenbeuving, R. M., additional, Heideman, R. G., additional, Fan, Y., additional, Boller, K. J., additional, and Barry, L. P., additional

Published
2018
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81. Target development for LWFA experiments at HZDR: Supersonic gas jets and plasma waveguides

Author

Köhler, A., Messmer, M., Couperus, J. P., Zarini, O., Jochmann, A., Wolterink, T., Bastiaens, B., Boller, K., Irman, A., and Schramm, U.

Subjects
Physics::Optics
Abstract

Laser wakefield acceleration (LWFA) has emerged as a promising concept for the next generation of high energy electron accelerators. To attain highest possible particle energies in this acceleration scheme, high intensity laser beam must be maintained over distances much longer that the Rayleigh length. Therefore laser guiding is necessary to counteract the diffraction induced divergence of the beam. For this, a plasma channel is created inside a capillary via the concept of slow capillary discharge and characterized using an interferometric method. It is shown that the plasma channel has a refractive index profile suitable for laser guiding. As the first step, the pressure range and the time window in which guiding can occur are determined by guidance of a He-Ne laser. With the gained knowledge, laser guiding capabilities of a pulse Ti:Sa laser are evaluated. The results show a broad, easy to realize parameter window for pressure and time in which high laser transmission of above 75% are achieved.

Published
2015

82. Enabling acousto-optic devices for glass waveguide

Author

Garcia Porcel, M.A., Hoekman, M., Dekkers, M., Stoffer, R., Dekker, R., Leinse, A., van der Slot, P.J.M., Boller, K.-J., Garcia-Blanco, S.M., Boller, K.J., Faculty of Science and Technology, and Laser Physics & Nonlinear Optics

Published
2014

83. Recent Updates to the Optical Propagation Code OPC

Author

van der Slot, P.J.M., Boller, K.-J., Faculty of Science and Technology, and Laser Physics & Nonlinear Optics

Subjects
Physics::Accelerator Physics
Abstract

In order to understand and design free-electron lasers (FELs), simulation codes modeling the interaction of electrons with a co-propagating optical field in the magnetic field of an undulator are essential. However, propagation of the optical field outside the undulator is equally important for evaluation of the optical field at the location of the application or to model FEL oscillators. The optical propagation code OPC provides such capabilities and can interface with FEL gain codes like GENESIS 1.3, MEDUSA and MINERVA. Here we present recent additions and modifications to the code that improves the speed of the code and extends the modeling capabilities. These include amongst other, inline diagnostics that results in considerable faster runtimes, the ability to convert from free-space modes to guided modes (currently only cylindrical waveguides), and the possibility to determine the spectrum at each transverse location. The latter opens the possibility to include dispersion in the optical propagation.

Published
2014

84. Oxidation and stoichiometry studies of pulsed laser ablation plasmas

Author

Orsel, K., Bastiaens, H.M.J., Groenen, R., Koster, G., Beks-Peerenboom, K., van Dijk, J., Rijnders, A.J.H.M., Boller, K.-J., Laser Physics & Nonlinear Optics, and Inorganic Materials Science

Subjects
METIS-308613
Abstract

Pulsed Laser Deposition (PLD) is a versatile technique to deposit complex materials. However, knowledge on the PLD process is based largely on experimental research examining what parameters appear to provide the best result for a specic setup and material. The goal of our research is to progress towards an improved understanding and control of PLD for scaling up to large-area deposition while maintaining full control on lm growth, i.e., to the level of atomic precision. To map the spatial and temporal evolution of the ablation plasma, we built a PLD test system that allows for in-situ laser induced uorescence imaging and absorption spectroscopy measurements. From this, it is possible to generate a 3D map of the absolute material ux towards the substrate, which is essential for obtaining a fundamental understanding of the plasma chemistry and evolution. The stoichiometry of the plasma plume, the oxidation of specic species and the propagation speed of the material can all be controlled by varying the ablation laser uency, the background pressure and the background gas mixture (typically Ar and O2). This in turn allows us to ne-tune the properties of the layers that are grown with these plasmas. Here, we present our recent results on the oxidation and stoichiometry of species in plasmas created by laser ablation of SrTiO3 and LaAlO3.

Published
2014

85. Coherent control of high harmonic generation in a large-volume capillary for seeding of free-electron lasers

Author

Goh, S.J., Reinink, J., Tao, Y., Bastiaens, H.M.J., van der Slot, P.J.M., Biedron, S.G., Danailov, M.B., Milton, S.V., Herek, J., Boller, K.-J., Faculty of Engineering Technology, Faculty of Science and Technology, Laser Physics & Nonlinear Optics, and Optical Sciences

Subjects
METIS-308827, Physics::Optics, Physics::Atomic Physics
Abstract

FEL-1 at FERMI@Elettra is a seeded free-electron laser using sub-harmonic seeding to generate soft x-rays down to 10 nm. The current seed laser, a standard solid-state laser followed by frequency quadrupling in nonlinear crystals, has a minimum wavelength of 200 nm. Injecting much shorter seed-laser wavelengths, for which high-harmonic generation (HHG) is of high promise, can shorten the laser output wavelength significantly. However, the minimum seed pulse energy required is not readily available with standard approaches to HHG. To increase the energy available in a particular harmonic for seeding, we use a gas-filled capillary with a large diameter (500 μm), pumped by an 8 mJ, 35 fs Ti:Sapphire laser. A wide capillary allows a large gas volume for HHG, thereby increasing the output energy. We also investigate the coherent control of HHG by shaping the spectral phase of the drive laser using an acousto-optic programmable dispersive filter. Here, we use a learning algorithm with the objective to simultaneously tune and selectively enhance an individual harmonic order. We present first results including pressure dependent harmonic output energy, spectrum and beam stability, as these are important for seeding of FELs. Further, we discuss initial experiments with coherent control that has shown selective enhancement up to a factor of 10.

Published
2014

89. Tomographic characterisation of gas-jet targets for laser wakefield acceleration

Author

Couperus, J. P., Köhler, A., Wolterink, T. A. W., Jochmann, A., Zarini, O., Bastiaens, H. M. J., Boller, K. J., Irman, A., Schramm, U., Couperus, J. P., Köhler, A., Wolterink, T. A. W., Jochmann, A., Zarini, O., Bastiaens, H. M. J., Boller, K. J., Irman, A., and Schramm, U.

Abstract

Laser wakefield acceleration (LWFA) has emerged as a promising concept for the next generation of high energy electron accelerators. The acceleration medium is provided by a target that creates a local well-defined gas-density profile inside a vacuum vessel. Target development and analysis of the resulting gas-density profiles is an important aspect in the further development of LWFA. Gas-jet targets are widely used in regimes where relatively high electron densities over short interaction lengths are required (up to several millimetres interaction length, plasma densities down to ~1018 cm-3). In this paper we report a precise characterisation of such gas-jet targets by a laser interferometry technique. We show that phase shifts down to 4 mrad can be resolved. Tomographic phase reconstruction enables detection of non-axisymmetrical gas-density profiles which indicates defects in cylindrical nozzles, analysis of slit-nozzles and nozzles with an induced shock-wave density step. In a direct comparison between argon and helium jets we show that it cannot automatically be assumed, as is often done, that a nozzle measured with argon will provide the same gas density with helium.

Published
2016

94. Numerical modeling of seeded FWM in silicon nitride waveguides for CARS

Author

Epping, J.P., Kues, M., van der Slot, P.J.M., Lee, C.J., Fallnich, C., Boller, K.-J., Faculty of Science and Technology, and Laser Physics & Nonlinear Optics

Abstract

We propose and theoretically investigate a light source for CARS based on seeded four-wave mixing in silicon nitride waveguides. A tuning range (1290-2750 cm-1) is expected via pumping at a wavelength of 1058 nm and the pump power is calculated to be one order of magnitude lower than what was previously reported.

Published
2013

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