Selcuk Akturk

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Precise ablation of metals using tightly fo-cused femtosecond laser pulses with intensities close to the damage threshold can yield sub-wavelength, nanometer-sized holes or craters. These structures in metals can exhibit plasmonic effects, thereby affecting the interactions involved. We numerically simulate light propagation inside such holes and model the(More)
Four-quadrature spectral interferometry using balanced coherent detection enables single-shot full-field characterization of complex-shaped optical waveforms with near quantum-limited sensitivity. A 90° optical hybrid places a waveform in four-quadrature-phases with a stronger, well-characterized reference pulse. Measurement of the four spectra with an(More)
We demonstrate compression of high-energy ultrashort laser pulses by nonlinear propagation inside gas-filled planar hollow waveguides. We adjust the input beam size along the nonguided dimension of the planar waveguide to restrain the intensity below photoionization, while the relatively long range guided propagation yields significant self-phase modulation(More)
Using a recently developed technique (SEA TADPOLE) for easily measuring the complete spatiotemporal electric field of light pulses with micrometer spatial and femtosecond temporal resolution, we directly demonstrate the formation of theo-called boundary diffraction wave and Arago's spot after an aperture, as well as the superluminal propagation of the spot.(More)
By immersing a conventional glass axicon in index-matching liquid, we generated high quality, tunable, quasi non-diffracting Bessel beams. The aberrations resulting from the roundness of the axicon tip are minimized when a large base angle is used in liquid-immersion. This configuration also allows coarse and fine tunability through changing the liquid and(More)
We demonstrate a simple, essentially alignment-free Transient-Grating Frequency-Resolved-Optical-Gating arrangement using a simple input mask that separates the input beam into three beams and a Fresnel biprism that crosses and delays them. It naturally operates single shot and has no moving parts. It is also extremely broadband and hence should be ideal(More)
We demonstrate frequency-resolved optical gating (FROG) for measuring the full intensity and phase of several-optical-cycle 1.5-µm pulses generated from a Kerr-lens mode-locked (KLM) Cr 4+ :YAG laser. This involves the use of an angle-dithered second-harmonic-generation crystal to achieve the full pulse bandwidth despite the use of a relatively thick(More)
Laser pulses with picosecond and femtosecond durations are now indispensable tools in many scientific disciplines. These ultrashort pulses provide unique temporal resolutions for investigations of phenomena taking place in comparable time ranges. In addition, optical energies squeezed into such short time windows yield extremely high peak powers and(More)