Characteristics of Nanopatterns and the Associated Thermal Mechanisms During Near Field Laser-Material Interaction of Nanosecond Laser on Different Targets

2009 ◽  
Author(s):  
Vijay M. Sundaram ◽  
Sy-Bor Wen
Keyword(s):  
Near Field ◽  
Target Material ◽  
Optical Microscope ◽  
Laser Source ◽  
Nanosecond Laser ◽  
Metallic Surfaces ◽  
Experimental Conditions ◽  
Laser Material ◽  
Material Conditions ◽  
Material Interaction

Nano-patterns are generated on semiconducting and metallic surfaces through coupling an apertured near field scanning optical microscope (NSOM) with a pulsed laser source in this study. To understand the dominant mechanisms for the generation of the nano-patterns, a series of experimental measurement of the size and shape of nano-patterns generated on targets under different experimental conditions with different targets is conducted. The characteristic dimensions of nano-patterns show dependence on optical properties of the target material. The qualitative trend of the variation of nano-patterns as a function of laser and material conditions indicates that the dominant mechanisms for the generation of nano-patterns through a combination of nanosecond laser and an apertured NSOM under different conditions studied is near field laser-material interaction.

scholarly journals Investigation of Laser-material Interaction in Case of Aluminium Brazing Process

2018 ◽  
Author(s):  
Tamás Markovits ◽  
András Jászberényi
Keyword(s):  
Co2 Laser ◽  
Laser Heating ◽  
Laser Energy ◽  
Research Work ◽  
Base Material ◽  
Laser Source ◽  
Laser Material ◽  
Heating Source ◽  
Laser Absorption ◽  
Material Interaction

This research work is connected to the applicability of laser source in case of brazing of aluminium materials. Based on our earlier research results it become clear that the brazing flux material is able to improve the laser absorption in case CO2 laser source. A new brazing flux material (Fontargen F 400 MD EVO2) and the CO2 laser interactions were investigated to determine the applicability of laser as a heating source. The application of laser strongly depend on the value of absorption of laser energy into the aluminium base material. From our new result it can be seen that the applied flux can improve the laser absorption, thus the laser heating, but the implementation of brazing process with this flux material brings further challenges.

Nanometer-Scale Laser Direct-Write Using Near-Field Optics

MRS Bulletin ◽  
2007 ◽  
Vol 32 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Costas P. Grigoropoulos ◽  
David J. Hwang ◽  
Anant Chimmalgi
Keyword(s):  
Structural Changes ◽  
Near Field ◽  
Target Material ◽  
Optical Microscope ◽  
Nanometer Scale ◽  
Direct Write ◽  
Feature Size ◽  
Near Field Optics ◽  
Near Field Scanning ◽  
Laser Direct Write

AbstractThis article summarizes research on laser-based processing and structuring of materials at the nanoscale using optical near-field schemes. Both apertureless and tapered fiber near-field scanning optical microscope probes can deliver highly confined irradiation at sufficiently high intensities to cause morphological and structural changes in materials at the nanometer level. The energy emitted by the probes and the absorption within the target material are predicted by carrying out calculations of the near-field electromagnetic distribution. The effects of shrinking laser beam dimensions compete with the energy diffusion into the target material. Experimental results have shown well-controlled subtractive material modification with minimum feature size in the neighborhood of 10 nm. Precise patterning can be achieved via laser-assisted chemical etching. Control of the nucleation of nanostructures via rapid melting and crystallization is demonstrated. The article concludes with an outlook to applications.

Nanodomain shock wave in near-field laser–material interaction

2007 ◽  
Vol 369 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Xuhui Feng ◽  
Xinwei Wang
Keyword(s):  
Shock Wave ◽  
Near Field ◽  
Laser Material ◽  
Material Interaction

Selective Laser Sintering of Resin-Coated Sands—Part I: The Laser-Material Interaction

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Fabrizio Quadrini ◽  
Loredana Santo
Keyword(s):  
Focal Spot ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Laser Source ◽  
Layer By Layer ◽  
Sintering Process ◽  
New Approach ◽  
Laser Material ◽  
Definition Of ◽  
Material Interaction

Selective laser sintering of precoated sands is a process utilized to produce molds and cores for rapid casting by adding sand layer by layer and heating it using a laser beam. During the process, the resin flows and binds the grains; subsequently, an oven is used for the postcuring treatment to complete the curing of the resin. The aim of this paper was to study the laser-material interaction using a diode laser to directly obtain the material consolidation. It was the first step in the definition of a new approach for process investigation and innovation. Two main aspects were investigated with the laser source in a standstill position: first, the influence of the laser power, the location of the focal spot, and the exposure time on sand consolidation; second, the shape and dimension of cured samples depending on the process parameters. The experimental data, in terms of weight and size of the hardened sands, were analyzed, and a master curve was found. In Part II of this paper the selective laser sintering process will be implemented to produce shells.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

scholarly journals Simulation of the laser-material interaction of ultrashort pulse laser processing of silicon nitride workpieces and the key factors in the ablation process

2021 ◽  
Author(s):  
Babak Soltani ◽  
Faramarz Hojati ◽  
Amir Daneshi ◽  
Bahman Azarhoushang
Keyword(s):  
Mathematical Model ◽  
Laser Ablation ◽  
Pulse Laser ◽  
Ultrashort Pulse ◽  
Laser Processing ◽  
Laser Power ◽  
Removal Rate ◽  
Ultrashort Pulse Laser ◽  
Laser Material ◽  
Material Interaction

AbstractUnderstanding the laser ablation mechanism is highly essential to find the effect of different laser parameters on the quality of the laser ablation. A mathematical model was developed in the current investigation to calculate the material removal rate and ablation depth. Laser cuts were created on the workpiece with different laser scan speeds from 1 to 10 mm s−1 by an ultrashort pulse laser with a wavelength of about 1000 nm. The calculated depths of laser cuts were validated via practical experiments. The variation of the laser power intensity on the workpiece’s surface during laser radiation was also calculated. The mathematical model has determined the laser-material interaction mechanism for different laser intensities. The practical sublimation temperature and ablated material temperature during laser processing are other data that the model calculates. The results show that in laser power intensities (IL) higher than 1.5 × 109 W cm−2, the laser-material interaction is multiphoton ionisation with no effects of thermal reaction, while in lower values of IL, there are effects of thermal damages and HAZ adjacent to the laser cut. The angle of incidence is an essential factor in altering incident IL on the surface of the workpiece during laser processing, which changes with increasing depth of the laser cut.

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