scholarly journals Competition Effects during Femtosecond Laser Induced Element Redistribution in Ba- and La-Migration Based Laser Written Waveguides

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3185
Author(s):  
Manuel Macias-Montero ◽  
Pedro Moreno-Zárate ◽  
Francisco Muñoz ◽  
Belén Sotillo ◽  
Marina Garcia-Pardo ◽  
...  
Keyword(s):  
Laser Processing ◽  
Optical Waveguides ◽  
Phosphate Glasses ◽  
Competition Effect ◽  
Competition Effects ◽  
Fs Laser ◽  
Index Contrast ◽  
The Cross ◽  
Element Redistribution ◽  
Element Migration

Fs-laser induced element redistribution (FLIER) has been a subject of intensive research in recent years. Its application to various types of glasses has already resulted in the production of efficient optical waveguides, tappers, amplifiers and lasers. Most of the work reported on FLIER-based waveguides refers to structures produced by the cross-migration of alkali (Na, K) and lanthanides (mostly La). The latter elements act as refractive index carrying elements. Herein, we report the production of Ba-based, FLIER-waveguides in phosphate glass with an index contrast > 10−2. Phosphate glasses modified with the same amount of Na2O and K2O, and variable amounts of BaO and/or La2O3 were used to produce the FLIER-waveguides with Ba and or La acting as index carriers. Ba-only modified glasses show a waveguide writing threshold and light guiding performance comparable to that of La-based structures. However, mixed Ba-La glasses show a much higher element migration threshold, and much smaller compositionally modified regions. This behavior is consistent with a competition effect in the cross-migration of both elements (Ba and La) against the alkalis. Such an effect can be applied to inhibit undesired element redistribution effects in fs-laser processing applications in multicomponent glasses.

scholarly journals Role of the La/K Compositional Ratio in the Properties of Waveguides Written by Fs-Laser Induced Element Redistribution in Phosphate-Based Glasses

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1275 ◽  
Author(s):  
Pedro Moreno-Zarate ◽  
Francisco Muñoz ◽  
Belen Sotillo ◽  
Manuel Macias-Montero ◽  
Julia Atienzar ◽  
...  
Keyword(s):  
Refractive Index ◽  
Glass Composition ◽  
Near Field ◽  
Phosphate Glasses ◽  
Femtosecond Laser Irradiation ◽  
Local Modification ◽  
Fs Laser ◽  
Index Contrast ◽  
Element Redistribution ◽  
Local Enrichment

The local modification of the composition of glasses by high repetition femtosecond laser irradiation is an attractive method for producing photonic devices. Recently, the successful production of waveguides with a refractive index contrast (Δn) above 10−2 by fs-laser writing has been demonstrated in phosphate glasses containing La2O3 and K2O modifiers. This large index contrast has been related to a local enrichment in lanthanum in the light guiding region accompanied by a depletion in potassium. In this work, we have studied the influence of the initial glass composition on the performance of waveguides that are produced by fs-laser induced element redistribution (FLIER) in phosphate-based samples with different La and K concentrations. We have analyzed the contribution to the electronic polarizability of the different glass constituents based on refractive index measurements of the untreated samples, and used it to estimate the expected index contrast caused by the experimentally measured local compositional changes in laser written guiding structures. These estimated values have been compared to experimental ones that are derived from near field images of the guided modes with an excellent agreement. Therefore, we have developed a method to estimate before-hand the expected index contrast in fs-laser written waveguides via FLIER for a given glass composition. The obtained results stress the importance of considering the contribution to the polarizability of all the moving species when computing the expected refractive index changes that are caused by FLIER processes.

When an Industry Peer Is Accused of Financial Misconduct: Stigma versus Competition Effects on Non-accused Firms

2021 ◽  
pp. 000183922110206
Author(s):  
Ivana Naumovska ◽  
Dovev Lavie
Keyword(s):  
Competitive Dynamics ◽  
Negative Consequences ◽  
Competition Effect ◽  
Market Returns ◽  
Stock Market Returns ◽  
Fine Grained ◽  
Competition Effects ◽  
Financial Misconduct ◽  
Industry Peers ◽  
The U.S

Research on misconduct suggests that accusations against industry peers generate negative consequences for non-accused firms (a “stigma effect”). Yet, building on research on competitive dynamics, we infer that such accusations can benefit non-accused firms that compete with these peers (a “competition effect”). To reconcile these opposing perspectives, we posit that the negative stigma effect will increase with greater product market overlap between the non-accused firm and its accused peer, up to a point, beyond which the positive competition effect will counterbalance it. We further conjecture that the competition effect will be relatively more pronounced when the market classification used by investors for assessing the market overlap is more fine-grained. Accordingly, we suggest that more sophisticated investors, who rely on more fine-grained market classifications, increase their shareholdings in non-accused firms to a greater extent than less sophisticated investors as the market overlap between the non-accused firm and the accused peer increases. Using elaborate data on products and investments, we analyze investors’ shareholdings and stock market returns of non-accused firms in the U.S. software industry following accusations of financial misconduct by their industry peers, and we find support for our predictions. Our study elucidates the interplay between stigma and competition following misconduct by industry peers.

Electrophysiologic Correlates of Attention versus Distraction in Young and Elderly Listeners

2002 ◽  
Vol 13 (07) ◽  
pp. 383-391 ◽  
Author(s):  
Albert R. De Chicchis ◽  
Michael Carpenter ◽  
Jerry L. Cranford ◽  
Murvin R. Hymel
Keyword(s):  
Selective Attention ◽  
Evoked Potential ◽  
The Elderly ◽  
Auditory Evoked Potential ◽  
Competition Effect ◽  
Specific Target ◽  
Attention Effect ◽  
Competition Effects ◽  
Significant Attention ◽  
Versus Stimulus

This study examined the effects of selective attention versus stimulus competition on the late auditory evoked potential (LAEP) in 20 young and 20 elderly listeners. In a series of test runs, different oddball tonal sequences were presented to one or both ears, and listeners were instructed to attend to tones at a specific target ear. Peak amplitudes were recorded for the N1, P2, and the early and late N2 components of the LAEP. Significant attention effects were found for all four components. N1 amplitudes increased significantly when participants attended to the target stimuli, whereas the amplitudes of P2, N2e, and N2l decreased. For all LAEP components except N2l, the attention effect did not differ between young and elderly listeners. Significant competition effects also were found for all four components. Amplitudes were significantly larger in monaural than binaural conditions for all components except N2l. The magnitude of this competition effect also was significantly larger for the young listeners than the elderly for all components except N1. These results suggest that the ability to attend selectively to sounds may be more resistant to normal aging than are effects related to stimulus competition.

FS laser processing of bio-polymer thin films for studying cell-to-substrate specific response

2016 ◽  
Vol 382 ◽  
pp. 178-191 ◽  
Author(s):  
A. Daskalova ◽  
Chandra S.R. Nathala ◽  
P. Kavatzikidou ◽  
A. Ranella ◽  
R. Szoszkiewicz ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Processing ◽  
Polymer Thin Films ◽  
Specific Response ◽  
Fs Laser

Ultrafast Laser Processing for Lab-on-a-Chip Device Manufacture

2004 ◽  
Vol 850 ◽  
Author(s):  
Koji Sugioka ◽  
Ya Cheng ◽  
Katsumi Midorikawa
Keyword(s):  
Heat Treatment ◽  
Laser Processing ◽  
Lab On A Chip ◽  
Ultrafast Laser ◽  
Wet Etching ◽  
Direct Write ◽  
Electric Control ◽  
Fs Laser ◽  
Laser Direct Write ◽  
Hollow Microstructures

ABSTRACT3D microstructuring of photosensitive glass is demonstrated by femtosecond (fs) laser for lab-on-a-chip manufacture. True 3D hollow microstructures embedded in the glass are fabricated by the fs laser direct write followed by heat treatment and successive wet etching. A variety of microcomponents for a lab-on-a-chip device like a microfluidics, a microvalve, a microoptics, a microlaser, etc. are fabricated by using this technique. The fs laser direct write process is also applied for selective metallization of internal walls of the hollow microstructures embedded in the glass for electric control of movement of the micromechanical components in the lab-on-a-chip device.

One-Step Fabrication and Functionalization of Nanostructured Silicon Surfaces for Advanced Sensing Applications

2020 ◽  
Vol 312 ◽  
pp. 154-159
Author(s):  
Alexander Yuryevich Mironenko ◽  
Mikhail Tutov ◽  
Alexander Konstantinovich Chepak ◽  
Eugeny Mitsai ◽  
Alexander A. Sergeev ◽  
...  
Keyword(s):  
Laser Processing ◽  
Laser Energy ◽  
High Spatial Frequency ◽  
Laser Pulses ◽  
Successful Implementation ◽  
Experimental Conditions ◽  
Sensing Applications ◽  
Direct Laser ◽  
Fs Laser ◽  
One Step

Direct laser processing of various materials with nano- and femtosecond (fs) laser pulses is known to be a facile and inexpensive technology for fabrication of various surface morphologies. Since ultrafast deposition of the laser energy to target material typically creates unique experimental conditions with extremely high pressure and temperature, we hypothesized that carrying out this process in anhydrous non-oxidizing environment containing functionalizing agent (fluorophore with vinyl functional group) will allow one-step fabrication and subsequent functionalization of the surface of high-n material. In this paper, we demonstrate successful implementation of this idea by fabricating high-spatial-frequency laser-induced periodic surface structures (LIPSS) via direct fs-pulse ablation of bulk crystalline Si wafer immersed in solution of N-vinylcarbazole in toluene. Laser processing with linearly polarized fs-laser pulses was found to produce LIPSS with a characteristic period around 100 nm functionalized with N-vinylcarbazole molecules via photo-activated hydrosililation reaction. The unique LIPSS with hierarchical roughness and remarkable light trapping performance functionalized with sensory fluorophore show high sensitivity due to implementation of surface enhanced fluorescence effect. By using N-vinylcarbazole as functionalizing agent we demonstrate one-step fabrication of high-performance sensor for detecting nitrobenzene in water with a detection limit of 40 nM.

scholarly journals Femtosecond Laser Fabrication of Stable Hydrophilic and Anti-Corrosive Steel Surfaces

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3428 ◽  
Author(s):  
Christina Lanara ◽  
Alexandros Mimidis ◽  
Emmanuel Stratakis
Keyword(s):  
Laser Processing ◽  
High Performance ◽  
Single Step ◽  
Consumer Products ◽  
Step Method ◽  
Corrosion Properties ◽  
Gas Atmosphere ◽  
Fs Laser ◽  
Steel Surfaces ◽  
Background Gas

We report on a novel single-step method to develop steel surfaces with permanent highly hydrophilic and anti-corrosive properties, without employing any chemical coating. It is based on the femtosecond (fs) laser processing in a saturated background gas atmosphere. It is particularly shown that the fs laser microstructuring of steel in the presence of ammonia gas gives rise to pseudoperiodic arrays of microcones exhibiting highly hydrophilic properties, which are stable over time. This is in contrast to the conventional fs laser processing of steel in air, which always provides surfaces with progressively increasing hydrophobicity following irradiation. More importantly, the surfaces subjected to fs laser treatment in ammonia exhibit remarkable anti-corrosion properties, contrary to those processed in air, as well as untreated ones. The combination of two functionalities, namely hydrophilicity and corrosion resistance, together with the facile processing performed directly onto the steel surface, without the need to deposit any coating, opens the way for the laser-based production of high-performance steel components for a variety of applications, including mechanical parts, fluidic components and consumer products.

scholarly journals Thermally Resilient Planar Waveguides in Novel nc-YSZ Transparent Ceramic by fs Laser Pulses

2021 ◽  
Vol 9 ◽  
Author(s):  
Gabriel R. Castillo ◽  
Cecilia Burshtein ◽  
Gottlieb Uahengo ◽  
Elías H. Penilla ◽  
Yasmín Esqueda-Barrón ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Planar Waveguides ◽  
Stabilized Zirconia ◽  
Micro Raman Spectroscopy ◽  
Xps Characterization ◽  
Polycrystalline Ceramic ◽  
Fs Laser ◽  
Index Contrast ◽  
Waveguide Fabrication ◽  
Potential Use

We report on thermally resilient planar waveguides fabricated on nc-YSZ by direct fs-laser inscription in transparent nc-yttria stabilized zirconia (nc-YSZ) polycrystalline ceramic. The waveguides consisted of rectangular sections (4.5 × 2 mm2) on the surface of the sample. Optical characterization at 633 and 810 nm was performed. We estimate a laser-induced refractive index contrast of 10–4. Post-waveguide-fabrication thermal annealing treatments at 750°C for 24 h were carried out to test the resilience of the waveguides and to further reduce the waveguide losses. Both micro-Raman spectroscopy and XPS characterization revealed unmodified lattice and steady chemical features, which are consistent with the waveguide thermal resilience. Our results suggest a promising potential use of nc-YSZ in harsh and high temperature demanding photonic environments.

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