41,620 research outputs found
New science and art of femtosecond laser writing
No full textCommon beliefs that laser writing does not change when reversing beam scan or propagation direction are challenged. Recently discovered phenomena of quill and non-reciprocal femtosecond laser writing in glasses and crystals are reviewed
Dataset for Microengineering of Optical Properties of GeO2 Glass by Ultrafast Laser Nanostructuring
No full textData for the paper F. Zhang, A. Cerkauskaite, R. Drevinskas, P. G. Kazansky, J. Qiu, Advanced Optical Materials 2017, 1700342. </span
Channel waveguide lasers produced by femtosecond and picosecond direct laser writing in Ti:sapphire crystals
No full textFemtosecond-laser-written Ti:sapphire channel waveguides lase at ~798.25 nm above a threshold pump power of 84 mW with output power and slope efficiency of 143 mW and 23.5%, respectively. Lasing was also observed in picosecond-laser-written channels
The art of femtosecond laser writing
No full textCommon beliefs that laser writing does not change when reversing beam scan or propagation direction are challenged. Recently discovered phenomena of quill and non-reciprocal femtosecond laser writing in glasses and crystals are reviewed
Ultrafast laser calligraphy
No full textControl of structural modifications inside transparent materials by varying the direction of pulse front tilt is demonstrated, achieving a calligraphic style of writing. Anisotropic ultrafast laser cavitation in the irradiated region is observed
Femtosecond laser induced vortex anisotropy
No full textAnisotropic bubble chain structures are produced by ultrashort pulse laser irradiation in silica glass. Vortex anisotropy is observed in the irradiated volume
Harnessing ultrafast laser induced nanostructures in transparent materials
No full textMaterial processing with ultrafast lasers has attracted considerable interest due to a wide range of applications from laser surgery and integrated optics to optical data storage, 3D micro- and nano-structuring [1,2]. A decade ago it has been discovered that under certain irradiation conditions ordered sub-wavelength structures with features smaller than 20 nm can be formed in the volume of silica glass [3]. The effect of nanograting formation has attracted considerable interest with proposals of applications ranging from nanofluidics [4,5] to polarization control devices [6]
Efficient conversion to radial polarization in the two-micron band using a continuously space-variant half-waveplate
No full textWe demonstrate efficient conversion of a linearly-polarized Gaussian beam to a radially-polarised doughnut beam in the two-micron band using a continuously space-variant half-waveplate created by femtosecond writing of subwavelength gratings. The low scattering loss (<0.07) of this device indicates that it would be suitable for use with high power lasers
Polarization diffraction grating produced by femtosecond laser nanostructuring in glass
No full textWe demonstrate polarization sensitive diffractive optical element fabrication by femtosecond direct writing in the bulk of silica glass. Modulation of the anisotropic properties is produced by controlling light-induced self-assembled nano-gratings
New phenomena in ultrafast laser interaction with matter
No full textModification of transparent materials with ultrafast lasers has attracted considerable interest due to a wide range of applications including laser surgery, integrated optics, optical data storage, 3D micro- and nano-structuring [1]. Three different types of material modifications can be induced with ultrafast laser irradiation in the bulk of a transparent material, silica glass in particular: an isotropic refractive index change (type 1); a form birefringence associated with self-assembled nanogratings and negative refractive index change (type 2) [2, 3]; and a void (type 3). In fused silica the transition from type 1 to type 2 and finally to type 3 modification is observed with an increase of fluence. Recently, a remarkable phenomenon in ultrafast laser processing of transparent materials has been reported manifesting itself as a change in material modification by reversing the writing direction [4]. The phenomenon has been interpreted in terms of anisotropic plasma trapping and heating by a tilted front of the ultrashort laser pulse. Moreover a change in structural modification has been demonstrated in glass by controlling the direction of pulse front tilt, achieving a calligraphic style of laser writing which is similar in appearance to that inked with the bygone quill pen [5]. It has also been a common belief that in a homogeneous medium, the photosensitivity and corresponding light-induced material modifications do not change on the reversal of light propagation direction. More recently we have observed that in a non-centrosymmetric medium, modification of the material can be different when light propagates in opposite directions (KaYaSo effect) [6]. Non-reciprocity is produced by magnetic field (Faraday effect) and movement of the medium with respect to the direction of light propagation: parallel (Sagnac effect) or perpendicular (KaYaSo effect). We anticipate that the observed phenomena will open new opportunities in laser material processing, laser surgery, optical manipulation and data storage
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