New phenomena in interaction of intense ultrashort light pulses with transparent materials: from 3D self-assembled nanostructures to quill writing and nonreciprocal photosensitivity

Interaction of intense ulrashort light pulses with transparent materials reveal new ultrafast phenomena. Recent demonstrations of 3D nanoripple formation, ultrafast laser calligraphy and nonreciprocal photosensitivity are reviewed

Femtosecond laser nanostructuring of transparent materials: from bulk to fiber lasers

Progress in high power ultra-short pulse lasers has opened new frontiers in the physics of light-matter interactions and laser material processing. Recently there has been considerable interest in the application of femtosecond lasers to writing inside transparent materials and in particular to fabrication of three-dimensional microstructures

Material processing using ultrashort light pulses with tilted front

Femtosecond laser writing in glass is controlled by the polarization plane azimuth and intensity front tilt of light pulse. Polarization dependent distribution of extraordinary modifications along the light propagation direction is observed

Revealing extraordinary properties of femtosecond laser writing in glass

Modification 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 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 it have observed that in a noncentrosymmetric 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). Moreover a new phenomenon of ultrafast light blade, representing itself the first evidence of anisotropic sensitivity of isotropic medium to femtosecond laser radiation has been recently discovered [7]. We attribute these new phenomena to the anisotropy of the light-matter interaction caused by space-time couplings in ultrashort light pulses. This intrinsic spatio-temporal asymmetry of light opens an interesting opportunity in the control of photon flux interacting with a target submerged into condensed isotropic medium. We anticipate that the observed phenomena will open new opportunities in laser material processing, laser surgery, optical manipulation and data storage

Recent advances in femtosecond laser writing inside transparent materials

Modification 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 microand nano-structuring [1].T 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 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 it have observed that in a non-centrosymmetric medium, modification of the material can be different when light propagates in opposite directions (KaYaSo effect) [6]. Moreover a new phenomenon of ultrafast light blade, representing itself the first evidence of anisotropic sensitivity of isotropic medium to femtosecond laser radiation has been recently discovered [7]. We attribute these new phenomena to the anisotropy of the light-matter interaction caused by space-time couplings in ultrashort light pulses. We anticipate that the observed phenomena will open new opportunities in laser material processing, laser surgery, optical manipulation and data storage

Revealing new properties of light-matter interaction using ultrashort light pulses: from self-assembled nanostructures to hidden anisotropy of light beam

Interaction of intense ulrashort light pulses with transparent materials reveal new interesting properties and phenomena. Recent demonstrations of 3D nanoripple formation, nonreciprocal photosensitivity, ultrafast laser calligraphy and light blade effect due to hidden anisotropy of ultrafast laser beam are reviewed

The art and science of femtosecond laser writing

We demonstrate how femtosecond laser writing can challenge common beliefs in optics. Recently discovered phenomena of quill writing related to self-assembled nanostructuring in glasses and non-reciprocal laser writing in crystals are reviewe

Extraordinary stability of anisotropic femtosecond direct-written structures embedded in silica glass

In this letter we report the different response to temperature displayed by isotropic femtosecond written structures (type I_fs), and anisotropic ones (type II_fs), which are characterized by the presence of a self-assembled sub-wavelength periodic structure within the irradiated volume. We observe that the anisotropic structures display an extraordinary annealing behavior, namely, their photo induced change in refractive index increases with the annealing temperature. We explain our experimental results with a theoretical model

New phenomena in ultrafast laser micro-processing: from quill to non-reciprocal writing

Modification 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 (Figure 1a) [4]. The phenomenon has been interpreted in terms of anisotropic plasma 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 it have observed that in a non-centrosymmetric medium, modification of the material can be different when light propagates in opposite directions (KaYaSo effect, Figure 1b) [6]. In particular, when the direction of the femtosecond laser beam is reversed from +Z to – Z directions, the structures written in lithium niobate crystal when translating the beam along the +Y and –Y directions are mirrored. This is the first evidence of a new optical phenomenon of non-reciprocal photosensitivity. We interpret this effect in terms of light pressure and associated heat flow resulting in a temperature gradient in homogeneous media without inversion symmetry under uniform intense irradiation. 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