Konstantin Moutzouris

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Mutations in the human spastin gene (SPG4) cause the most prevalent form of autosomal dominant hereditary spastic paraplegia (HSP), a neurodegenerative disorder characterised by progressive weakness and spasticity of the lower limbs. We address the question of intracellular localisation of spastin. Using polyclonal antibodies against N-terminal spastin(More)
The performance of a confocal microscopy setup based on a single femtosecond fiber system is explored over a broad range of pump wavelengths for both linear and nonlinear imaging techniques. First, the benefits of a laser source in linear fluorescence excitation that is continuously tunable over most of the visible spectrum are demonstrated. The influences(More)
We report single-pass difference-frequency generation of mid-infrared femtosecond pulses tunable in the 3.2-4.8 microm range from a two-branch mode-locked erbium-doped fiber source. Average power levels of up to 1.1 mW at a repetition rate of 82 MHz are obtained in the mid infrared. This is achieved via nonlinear mixing of 170 mW, 65 fs pump pulses at a(More)
We report on a single-pass device that efficiently converts the broadband near-infrared output from a femtosecond fiber laser into a narrow spectrum in the visible. With fan-out poled MgO:LiNbO3 we obtain sub-picosecond, continuously tunable pulses in the 520-700 nm range. Conversion efficiencies as high as 30% are observed at typical pump power levels of(More)
We report the observation of second-harmonic generation by type I quasi phase matching in a GaAs-AlAs superlattice waveguide. Quasi phase matching was achieved through modulation of the nonlinear coefficient chi((2))(zxy), which we realized by periodically tuning the superlattice bandgap. Second-harmonic generation was demonstrated for fundamental(More)
We demonstrate the generation of femtosecond pulses in a synchronously pumped optical parametric oscillator (SPOPO) at the harmonics of pump repetition rate using a SPOPO cavity longer than the fundamental synchronous length. The SPOPO is based on a 1 mm crystal of periodically poled LiNbO(3) and pumped by a Kerr-lens mode-locked Ti:sapphire laser at 76(More)
In this letter, we report a novel device capable of generating ultrashort electrical pulses on a coplanar waveguide (CPW) by means of optical rectification. The device consists of a completely passive GaAs-based optical waveguide, which is velocity matched to a CPW line. Optical pulses are injected into the device and electrical pulses are collected at the(More)
We report efficient second-harmonic generation of femtosecond pulses in birefringently phase-matched GaAs/Al(2)O(3) waveguides pumped at 2.01mum. By use of pump pulses of ~200-fs duration and type I interaction, practical second-harmonic average powers of up to ~650muW were obtained, with an average input power of ~50muW. Waveguides of four different widths(More)
We report type I second-harmonic generation by use of first-order quasi-phase matching in a GaAs/AlAs symmetric superlattice structure with femtosecond fundamental pulses at 1.55 microm. Periodic spatial modulation of the bulklike second-order susceptibility chi(zxy)(2) was achieved with quantum-well intermixing for which the group III vacancies were(More)
In this paper, we review various nonlinear wavelength conversion experiments based upon a femtosecond erbium-fiber source operating at the telecommunication wavelength of 1.55 mum. By use of harmonic and sum frequency generation a nearly continuous ultra-wide band coverage from the ultraviolet through the entire visible to the near-infrared is achieved. The(More)
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