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1.
Appl Opt ; 60(4): 912-917, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33690397

RESUMO

The 35-fs-long pulses of a commercial Ti:sapphire amplifier are compressed to ∼20fs via self-phase modulation in bulk glass substrates. The cascading of both nonlinear broadening and dispersion compensation stages makes use of the increasing peak power in the successive nonlinear stages. As an application example, the compressed pulses are used for electro-optical sampling of terahertz waves created by optically pumped thin-film spin emitters.

2.
J Synchrotron Radiat ; 26(Pt 2): 328-332, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30855239

RESUMO

User operation at the European X-ray Free-Electron Laser Facility started at the SASE1 undulator beamline in fall 2017. The majority of the experiments utilize optical lasers (mostly ultrafast) for pump-probe-type measurements in combination with X-ray pulses. This manuscript describes the purpose-developed pump-probe laser system as installed at SASE1, implemented features and plans for further upgrades.

3.
Opt Express ; 26(24): 31299-31306, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30650718

RESUMO

The wavefront quality of white-light supercontinuum is crucial for applications like waveform synthesis or imaging. It has been here generated by 1030 nm centered sub-picosecond pulses in YAG and characterized with a Shack-Hartmann wavefront sensor across different parts of the spectrum. It shows a good wavefront quality of λ/11 and little dependence on the wavelength of the supercontinuum. The wavefront deformations are transferred from the driver laser wavefront to the supercontinuum independently of the wavelength.

4.
Opt Express ; 15(1): 176-82, 2007 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-19532233

RESUMO

In this paper we propose a structure to compensate the propagation loss of surface plasmons by using multiple quantum wells as a gain medium. We analyze the required gain for lossless surface plasmon propagation for different thicknesses and widths of the metallic guiding layer. We study the effects of the gain layers and a finite height superstrate on the surface plasmon mode and its propagation loss. It is shown that the gain required for lossless plasmon propagation is achievable with present technology.

5.
Opt Express ; 14(23): 11453-9, 2006 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-19529563

RESUMO

We report on the characterization of the ultrafast gain and refractive index dynamics of an InAs/InGaAsP self-assembled quantum dot semiconductor optical amplifier (SOA) operating at 1.55 mum through heterodyne pump-probe measurements with 150 fs resolution. The measurements show a 15 ps gain recovery time at a wavelength of 1560 nm, promising for ultrafast switching at >40 GHz in the important telecommunications wavelength bands. Ultrafast dynamics with 0.2-1.5 ps lifetimes were also found consistent with carrier heating and spectral hole burning. Comparing with previous reports on quantum dot SOAs at 1.1-1.3 mum wavelengths, we conclude that the carrier heating is caused by a combination of free-carrier absorption and stimulated transition processes.

6.
Opt Express ; 13(6): 1827-32, 2005 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-19495062

RESUMO

We theoretically demonstrate that optical discrete X-waves are possible in normally dispersive nonlinear waveguide arrays. We show that such X-waves can be effectively excited for a wide range of initial conditions and in certain occasions can be generated in cascade. The possibility of observing this family of waves in AlGaAs array systems is investigated in terms of pertinent examples.

7.
Appl Opt ; 43(15): 3010-7, 2004 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-15176187

RESUMO

The signal in optical coherence tomography is often modulated either in phase or by use of the Doppler modulation generated by a depth-scanning mechanism. The effect of each type of modulation on the signal's amplitude is evaluated. The advantages of each type of modulation in terms of immunity to phase noise and penetration depth are discussed in relation to two envelope detection schemes, i.e., lock-in detection and rms-to-dc conversion. Phase noise due to drifts and demodulation instabilities causes distortion of the signal envelope and can be responsible in part for the speckle appearance of the image.


Assuntos
Artefatos , Análise de Falha de Equipamento/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Pele/citologia , Tomografia de Coerência Óptica/instrumentação , Tomografia de Coerência Óptica/métodos , Animais , Camundongos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Processos Estocásticos
8.
Phys Rev Lett ; 93(9): 093903, 2004 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-15447103

RESUMO

We report our investigation of Kerr nonlinear beam interactions in discrete systems. The influence of power and the relative phase between two Gaussian shaped beams was investigated in detail by performing numerical simulations of the discrete nonlinear Schrödinger equation and comparing the results with experiments done in AlGaAs waveguide arrays. Good agreement between theory and experiment was obtained.

9.
Phys Rev Lett ; 91(14): 143907, 2003 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-14611529

RESUMO

We report the first experimental observation of discrete vector solitons in AlGaAs nonlinear waveguide arrays. These self-trapped states are possible through the coexistence of two orthogonally polarized fields and are stable in spite of the presence of four-wave mixing effects. We demonstrate that at sufficiently high power levels the two polarizations lock into a highly localized vector discrete soliton that would have been otherwise impossible in the absence of either one of these two components.

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