R. Leonhardt - Academia.edu (original) (raw)

Papers by R. Leonhardt

Research paper thumbnail of Femtosecond Dephasing Processes of Molecular Vibrations

Springer Series in Chemical Physics, 1988

Research paper thumbnail of PCF Based Optical Parametric Oscillators in the Visible

Advanced Photonics & Renewable Energy, 2010

ABSTRACT Recent advances in the drawing of photonic crystal fibres have enabled the development o... more ABSTRACT Recent advances in the drawing of photonic crystal fibres have enabled the development of fibre optic parametric oscillators generating coherent light tunable over wide regions of the visible and near IR spectrum.

Research paper thumbnail of All-fiber CW fiber optical parametric oscillator tunable over 240 nm

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

ABSTRACT In this paper we present a CW fiber optical parametric oscillator with a tuning range in... more ABSTRACT In this paper we present a CW fiber optical parametric oscillator with a tuning range in excess of 240 nm.

Research paper thumbnail of Simultaneous measurement of fibre nonlinearity and dispersion using Frequency Resolved Optical Gating

Research paper thumbnail of Atomic and molecular processes in external fields-Experimental verification of a one-parameter scaling law for the quantum and" classical" resonances of the atom-optics kicked rotor

Research paper thumbnail of Vector Modulational Instabilities in Photonic Crystal Fiber

2006 European Conference on Optical Communications, 2006

Two forms of vector modulation instability are observed in photonic crystal fiber. The strongly v... more Two forms of vector modulation instability are observed in photonic crystal fiber. The strongly varying dispersion of these fibers result in complicated phasematching curves. We experimentally demonstrate the existence of broad regions of parametric gain.

Research paper thumbnail of Parametric amplification in photonic crystal fibres

2008 IEEE/LEOS Winter Topical Meeting Series, 2008

Photonic crystal fibres have reinvigorated the study of parametric amplification in optical fibre... more Photonic crystal fibres have reinvigorated the study of parametric amplification in optical fibres through their special properties. Experimental results are presented for a range scalar and vector four wave mixing processes in photonic crystal fibres.

Research paper thumbnail of Depth-ambiguity free or polarization sensitive optical frequency domain imaging using the Pancharatnam-Berry phase

Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVI, 2012

ABSTRACT We present a method to obtain instantaneous quadrature components of the complex interfe... more ABSTRACT We present a method to obtain instantaneous quadrature components of the complex interferometric signal for depth-ambiguity free and full range optical frequency domain imaging, based on the Pancharatnam-Berry phase. This wavelength independent method allowed for a complex conjugate suppression of 45 dB, over an optical bandwidth of 80 nm. Furthermore, we investigated the versatility of this setup to perform polarization sensitive measurements. The sample Jones vector was fitted using the Newton-Raphson method, allowing sample birefringence and optical axis calculation.

Research paper thumbnail of Singlemode whitelight supercontinuum with 60 ps pump pulses in a photonic crystal fiber

Nonlinear Guided Waves and Their Applications, 2001

ABSTRACT

Research paper thumbnail of Scalar modulation instability in the normal dispersion regime by use of a photonic crystal fiber

Optics Letters, 2003

Modulation instability at high frequencies has been demonstrated in the normal dispersion regime ... more Modulation instability at high frequencies has been demonstrated in the normal dispersion regime by use of a photonic crystal fiber. This fiber-optic parametric generator provides efficient conversion of red pump light into blue and near-infrared light.

Research paper thumbnail of Characteristics of a visible modulation instability fiber laser

IEEE Journal of Quantum Electronics, 1994

Cross-phase modulation has been harnessed to construct a modulation instability laser operating a... more Cross-phase modulation has been harnessed to construct a modulation instability laser operating at 514.5 nm. The laser output consists of orthogonally polarized upshifted and downshifted sideband pulses separated in wavelength by 2.1 nm from the pump. The laser configuration has been found to generate a much more stable source of terahertz modulated light pulses than the single-pass configuration previously used

Research paper thumbnail of Experimental verification of a one-parameter scaling law for the quantum and “classical” resonances of the atom-optics kicked rotor

Physical Review A, 2005

We present experimental measurements of the mean energy in the vicinity of the first and second q... more We present experimental measurements of the mean energy in the vicinity of the first and second quantum resonances of the atom optics kicked rotor for a number of different experimental parameters. Our data is rescaled and compared with the one parameter ǫ-classical scaling function developed to describe the quantum resonance peaks. Additionally, experimental data is presented for the "classical" resonance which occurs in the limit as the kicking period goes to zero. This resonance is found to be analogous to the quantum resonances, and a similar one-parameter classical scaling function is derived, and found to match our experimental results. The width of the quantum and classical resonance peaks is compared, and their Sub-Fourier nature examined.

Research paper thumbnail of Wideband, low loss Terahertz propagation through kagome air-core microstructured fibers

2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011

ABSTRACT We present Terahertz (THz) time domain spectroscopy measurement of low loss microstructu... more ABSTRACT We present Terahertz (THz) time domain spectroscopy measurement of low loss microstructured kagome fibers using specially designed THz lenses. Losses as low as 0.6 cm−1, 20 times lower than the fiber cladding material loss have been achieved. Single-mode propagation in the air core with very low dispersion is experimentally observed for these fibers. Comparison between two different core diameters of kagome fiber reveals that a wider transmission window can be achieved with a larger diameter while the propagation loss remains in the same order of magnitude.

Research paper thumbnail of Hybrid hollow core fibers with embedded wires as THz waveguides

Optics Express, 2013

We experimentally demonstrate broadband terahertz (THz) pulse propagation through hollow core fib... more We experimentally demonstrate broadband terahertz (THz) pulse propagation through hollow core fibers with two or four embedded Indium wires in a THz time-domain spectroscopy (THz-TDS) setup. The hybrid mode is guided in the air core region with power attenuation coefficients of 0.3 cm(-1) and 0.5 cm(-1) for the two-wire and four-wire configurations, respectively.

Research paper thumbnail of 65 THz beat frequency observed from a scalar modulation instability experiment

CLEO/Europe. 2005 Conference on Lasers and Electro-Optics Europe, 2005.

Research paper thumbnail of Supercontinuum generation by stimulated Raman scattering and parametric four-wave mixing in photonic crystal fibers

Journal of the Optical Society of America B-Optical Physics, 2002

Research paper thumbnail of Terahertz beats of vibrational modes studied by femtosecond coherent Raman spectroscopy

Revue de Physique Appliquée, 1987

La Revue de Physique Appliquee parait ä raison de douze numeros par an. Les domaines couverts son... more La Revue de Physique Appliquee parait ä raison de douze numeros par an. Les domaines couverts sont : sciences des materiaux, physique des dispositifs electroniques, physique des fluides et mecanique, physique des transferts d'energie, physique des particules dans le vide et les plasmas, optique et lasers et instrumentation. Les manuscrits proposes doivent etre inedits, et rendre compte, soit de mesures originales relatives ä des phenomenes ou des materiaux connus, soit de met nodes experimentales ou d'appareillages nouveaux. La Revue publie egalement des notes breves presentant des resultats ou des dispositifs experimentaux originaux en deux pages de revue maximum, y compris resumes frangais, anglais et figures, ainsi que des mises au point en physique appliquee ou instrumentale. LANGUHS.-Fran?ais, anglais, allemand ou russe.

Research paper thumbnail of Experimental investigation of early-time diffusion in the quantum kicked rotor using a Bose-Einstein condensate

Physical Review E, 2004

We report the experimental observation of resonances in the early-time momentum diffusion rates f... more We report the experimental observation of resonances in the early-time momentum diffusion rates for the atom-optical delta-kicked rotor. In this work a Bose-Einstein condensate provides a source of ultra-cold atoms with an ultra-narow initial momentum distribution, which is then subjected to periodic pulses (or "kicks") using an intense far-detuned optical standing wave. A quantum resonance occurs when the momentum eigenstates

Research paper thumbnail of Beat frequencies of up to 16 THz generated via modulation instability in birefringent fibres

Optics Communications, 1995

... 30 (1994). [41 J. Rothenberg, Phys. Rev. A 42 (1990) 682. ( 51 JM Dudley, JD Harvey and R. Le... more ... 30 (1994). [41 J. Rothenberg, Phys. Rev. A 42 (1990) 682. ( 51 JM Dudley, JD Harvey and R. Leonhardt, l. Opt. Soc. Am. B 10 (1993) 840. ... Rev. A, 42 (1990), p. 682. [5] JM Dudley, JD Harvey and R Leonhardt. J. Opt. Soc. Am. B, 10 (1993), p. 840. [6] K Stenersen and RK Jain. ...

Research paper thumbnail of Parametric processes in microstructured and highly nonlinear optical fibres

Optical and Quantum Electronics - OPT QUANT ELECTRON, 2007

Optical parametric amplification is an important nonlinear process in photonic crystal fibres dri... more Optical parametric amplification is an important nonlinear process in photonic crystal fibres driven by the small effective area and the special dispersion characteristics of these fibres. Aside from its role in supercontinuum generation, parametric amplification can lead to efficient wavelength conversion, limited primarily by the uniformity of the diameter of currently available fibres. The related Bragg scattering process can be used for both wavelength conversion and optical switching, again limited by the physical characteristics of the fibres used.

Research paper thumbnail of Femtosecond Dephasing Processes of Molecular Vibrations

Springer Series in Chemical Physics, 1988

Research paper thumbnail of PCF Based Optical Parametric Oscillators in the Visible

Advanced Photonics & Renewable Energy, 2010

ABSTRACT Recent advances in the drawing of photonic crystal fibres have enabled the development o... more ABSTRACT Recent advances in the drawing of photonic crystal fibres have enabled the development of fibre optic parametric oscillators generating coherent light tunable over wide regions of the visible and near IR spectrum.

Research paper thumbnail of All-fiber CW fiber optical parametric oscillator tunable over 240 nm

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

ABSTRACT In this paper we present a CW fiber optical parametric oscillator with a tuning range in... more ABSTRACT In this paper we present a CW fiber optical parametric oscillator with a tuning range in excess of 240 nm.

Research paper thumbnail of Simultaneous measurement of fibre nonlinearity and dispersion using Frequency Resolved Optical Gating

Research paper thumbnail of Atomic and molecular processes in external fields-Experimental verification of a one-parameter scaling law for the quantum and" classical" resonances of the atom-optics kicked rotor

Research paper thumbnail of Vector Modulational Instabilities in Photonic Crystal Fiber

2006 European Conference on Optical Communications, 2006

Two forms of vector modulation instability are observed in photonic crystal fiber. The strongly v... more Two forms of vector modulation instability are observed in photonic crystal fiber. The strongly varying dispersion of these fibers result in complicated phasematching curves. We experimentally demonstrate the existence of broad regions of parametric gain.

Research paper thumbnail of Parametric amplification in photonic crystal fibres

2008 IEEE/LEOS Winter Topical Meeting Series, 2008

Photonic crystal fibres have reinvigorated the study of parametric amplification in optical fibre... more Photonic crystal fibres have reinvigorated the study of parametric amplification in optical fibres through their special properties. Experimental results are presented for a range scalar and vector four wave mixing processes in photonic crystal fibres.

Research paper thumbnail of Depth-ambiguity free or polarization sensitive optical frequency domain imaging using the Pancharatnam-Berry phase

Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVI, 2012

ABSTRACT We present a method to obtain instantaneous quadrature components of the complex interfe... more ABSTRACT We present a method to obtain instantaneous quadrature components of the complex interferometric signal for depth-ambiguity free and full range optical frequency domain imaging, based on the Pancharatnam-Berry phase. This wavelength independent method allowed for a complex conjugate suppression of 45 dB, over an optical bandwidth of 80 nm. Furthermore, we investigated the versatility of this setup to perform polarization sensitive measurements. The sample Jones vector was fitted using the Newton-Raphson method, allowing sample birefringence and optical axis calculation.

Research paper thumbnail of Singlemode whitelight supercontinuum with 60 ps pump pulses in a photonic crystal fiber

Nonlinear Guided Waves and Their Applications, 2001

ABSTRACT

Research paper thumbnail of Scalar modulation instability in the normal dispersion regime by use of a photonic crystal fiber

Optics Letters, 2003

Modulation instability at high frequencies has been demonstrated in the normal dispersion regime ... more Modulation instability at high frequencies has been demonstrated in the normal dispersion regime by use of a photonic crystal fiber. This fiber-optic parametric generator provides efficient conversion of red pump light into blue and near-infrared light.

Research paper thumbnail of Characteristics of a visible modulation instability fiber laser

IEEE Journal of Quantum Electronics, 1994

Cross-phase modulation has been harnessed to construct a modulation instability laser operating a... more Cross-phase modulation has been harnessed to construct a modulation instability laser operating at 514.5 nm. The laser output consists of orthogonally polarized upshifted and downshifted sideband pulses separated in wavelength by 2.1 nm from the pump. The laser configuration has been found to generate a much more stable source of terahertz modulated light pulses than the single-pass configuration previously used

Research paper thumbnail of Experimental verification of a one-parameter scaling law for the quantum and “classical” resonances of the atom-optics kicked rotor

Physical Review A, 2005

We present experimental measurements of the mean energy in the vicinity of the first and second q... more We present experimental measurements of the mean energy in the vicinity of the first and second quantum resonances of the atom optics kicked rotor for a number of different experimental parameters. Our data is rescaled and compared with the one parameter ǫ-classical scaling function developed to describe the quantum resonance peaks. Additionally, experimental data is presented for the "classical" resonance which occurs in the limit as the kicking period goes to zero. This resonance is found to be analogous to the quantum resonances, and a similar one-parameter classical scaling function is derived, and found to match our experimental results. The width of the quantum and classical resonance peaks is compared, and their Sub-Fourier nature examined.

Research paper thumbnail of Wideband, low loss Terahertz propagation through kagome air-core microstructured fibers

2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011

ABSTRACT We present Terahertz (THz) time domain spectroscopy measurement of low loss microstructu... more ABSTRACT We present Terahertz (THz) time domain spectroscopy measurement of low loss microstructured kagome fibers using specially designed THz lenses. Losses as low as 0.6 cm−1, 20 times lower than the fiber cladding material loss have been achieved. Single-mode propagation in the air core with very low dispersion is experimentally observed for these fibers. Comparison between two different core diameters of kagome fiber reveals that a wider transmission window can be achieved with a larger diameter while the propagation loss remains in the same order of magnitude.

Research paper thumbnail of Hybrid hollow core fibers with embedded wires as THz waveguides

Optics Express, 2013

We experimentally demonstrate broadband terahertz (THz) pulse propagation through hollow core fib... more We experimentally demonstrate broadband terahertz (THz) pulse propagation through hollow core fibers with two or four embedded Indium wires in a THz time-domain spectroscopy (THz-TDS) setup. The hybrid mode is guided in the air core region with power attenuation coefficients of 0.3 cm(-1) and 0.5 cm(-1) for the two-wire and four-wire configurations, respectively.

Research paper thumbnail of 65 THz beat frequency observed from a scalar modulation instability experiment

CLEO/Europe. 2005 Conference on Lasers and Electro-Optics Europe, 2005.

Research paper thumbnail of Supercontinuum generation by stimulated Raman scattering and parametric four-wave mixing in photonic crystal fibers

Journal of the Optical Society of America B-Optical Physics, 2002

Research paper thumbnail of Terahertz beats of vibrational modes studied by femtosecond coherent Raman spectroscopy

Revue de Physique Appliquée, 1987

La Revue de Physique Appliquee parait ä raison de douze numeros par an. Les domaines couverts son... more La Revue de Physique Appliquee parait ä raison de douze numeros par an. Les domaines couverts sont : sciences des materiaux, physique des dispositifs electroniques, physique des fluides et mecanique, physique des transferts d'energie, physique des particules dans le vide et les plasmas, optique et lasers et instrumentation. Les manuscrits proposes doivent etre inedits, et rendre compte, soit de mesures originales relatives ä des phenomenes ou des materiaux connus, soit de met nodes experimentales ou d'appareillages nouveaux. La Revue publie egalement des notes breves presentant des resultats ou des dispositifs experimentaux originaux en deux pages de revue maximum, y compris resumes frangais, anglais et figures, ainsi que des mises au point en physique appliquee ou instrumentale. LANGUHS.-Fran?ais, anglais, allemand ou russe.

Research paper thumbnail of Experimental investigation of early-time diffusion in the quantum kicked rotor using a Bose-Einstein condensate

Physical Review E, 2004

We report the experimental observation of resonances in the early-time momentum diffusion rates f... more We report the experimental observation of resonances in the early-time momentum diffusion rates for the atom-optical delta-kicked rotor. In this work a Bose-Einstein condensate provides a source of ultra-cold atoms with an ultra-narow initial momentum distribution, which is then subjected to periodic pulses (or "kicks") using an intense far-detuned optical standing wave. A quantum resonance occurs when the momentum eigenstates

Research paper thumbnail of Beat frequencies of up to 16 THz generated via modulation instability in birefringent fibres

Optics Communications, 1995

... 30 (1994). [41 J. Rothenberg, Phys. Rev. A 42 (1990) 682. ( 51 JM Dudley, JD Harvey and R. Le... more ... 30 (1994). [41 J. Rothenberg, Phys. Rev. A 42 (1990) 682. ( 51 JM Dudley, JD Harvey and R. Leonhardt, l. Opt. Soc. Am. B 10 (1993) 840. ... Rev. A, 42 (1990), p. 682. [5] JM Dudley, JD Harvey and R Leonhardt. J. Opt. Soc. Am. B, 10 (1993), p. 840. [6] K Stenersen and RK Jain. ...

Research paper thumbnail of Parametric processes in microstructured and highly nonlinear optical fibres

Optical and Quantum Electronics - OPT QUANT ELECTRON, 2007

Optical parametric amplification is an important nonlinear process in photonic crystal fibres dri... more Optical parametric amplification is an important nonlinear process in photonic crystal fibres driven by the small effective area and the special dispersion characteristics of these fibres. Aside from its role in supercontinuum generation, parametric amplification can lead to efficient wavelength conversion, limited primarily by the uniformity of the diameter of currently available fibres. The related Bragg scattering process can be used for both wavelength conversion and optical switching, again limited by the physical characteristics of the fibres used.