The role of an interface on Ni film removal and surface roughness after irradiation by femtosecond laser pulses

2013 ◽  
Vol 102 (18) ◽  
pp. 181602 ◽  
Author(s):  
Ryan D. Murphy ◽  
Ben Torralva ◽  
Steven M. Yalisove
Keyword(s):  
Surface Roughness ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

Characterization of Electrical Contacts on Silicon (100) after Ablation and Sulfur Doping by Femtosecond Laser Pulses

2013 ◽  
Vol 205-206 ◽  
pp. 358-363 ◽  
Author(s):  
Philipp Saring ◽  
Anna Lena Baumann ◽  
Stefan Kontermann ◽  
Wolfgang Schade ◽  
Michael Seibt
Keyword(s):  
Surface Roughness ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Sample Surface ◽  
Femtosecond Laser Pulses ◽  
Electrical Contacts ◽  
Single Shot ◽  
Excess Charge ◽  
Silicon Sample ◽  
Etching Depth

This paper investigates the influence of different number of laser pulses on contact behavior and conductivity of the surface layer of femtosecond laser microstructured, sulfur-doped silicon. Single shot laser processed silicon (Pink Silicon) is characterized by low surface roughness, whereas five shot laser processed silicon (Grey Silicon) has an elevated sulfur content with a surface roughness low enough to maintain good contacting. To laterally confine the laser induced pn-junction part of the Grey Silicon sample surface is etched off. The etching depth is confirmed to be sufficient to completely remove the active n-type sulfur layer. While Pink Silicon shows little or no lateral conductivity within the laser processed layer, Grey Silicon offers acceptable conductivity, just as expected by the fact of having incorporated a higher sulfur dopant content. Recombination dominates the irradiated regions of Pink Silicon and suppresses excess charge carrier collection. Grey Silicon, while showing sufficient lateral conductivity, still shows regions of lower conductivity, most likely dominated by the laser irradiation-induced formation of dislocations. According to our results, the optimum laser pulse number for electrical and structural properties is expected to be in the range between one and five laser pulses.

scholarly journals Understanding the Seeding Pulse-Induced Optical Amplification in N 2 + Pumped by 800 NM Femtosecond Laser Pulses

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 99
Author(s):  
Zhengquan Fan ◽  
Xiang Zhang ◽  
Qi Lu ◽  
Yu Luo ◽  
Qingqing Liang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Optical Gain ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Time Resolved ◽  
Optical Amplification ◽  
Pump Probe ◽  
Amplification Process ◽  
Energy Amplification

Nitrogen ions pumped by intense femtosecond laser pulses present an optical gain at 391.4 nm, evident by energy amplification of an injected resonant seeding pulse. We report a time-resolved measurement of the amplification process with seeding pulses having varying intensities. It is found that the amplification factor depends on the intensity of the seeding pulse and the effective temporal window for the optical gain becomes longer by applying more intense seeding pulses. These two features are in sharp contrast with classic pump-probe experiments, pinpointing the crucial role of macroscopic coherence and its dynamics during the lasing process. We further measure the temporal profile of the amplified emission for seeding pulse injected at different time delays. A complicated temporal behavior is observed, which highlights the nature of the superfluorescence.

scholarly journals Micromachining of Transparent Biocompatible Polymers Applied in Medicine Using Bursts of Femtosecond Laser Pulses

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1093
Author(s):  
Evaldas Kažukauskas ◽  
Simas Butkus ◽  
Piotr Tokarski ◽  
Vytautas Jukna ◽  
Martynas Barkauskas ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Femtosecond Laser ◽  
Contact Lenses ◽  
Laser Pulses ◽  
Laser Micromachining ◽  
Femtosecond Laser Pulses ◽  
Intraocular Lenses ◽  
Great Promise ◽  
Biocompatible Polymers ◽  
Mechanical Methods

Biocompatible polymers are used for many different purposes (catheters, artificial heart components, dentistry products, etc.). An important field for biocompatible polymers is the production of vision implants known as intraocular lenses or custom-shape contact lenses. Typically, curved surfaces are manufactured by mechanical means such as milling, turning or lathe cutting. The 2.5 D objects/surfaces can also be manufactured by means of laser micromachining; however, due to the nature of light–matter interaction, it is difficult to produce a surface finish with surface roughness values lower than ~1 µm Ra. Therefore, laser micromachining alone can’t produce the final parts with optical-grade quality. Laser machined surfaces may be polished via mechanical methods; however, the process may take up to several days, which makes the production of implants economically challenging. The aim of this study is the investigation of the polishing capabilities of rough (~1 µm Ra) hydrophilic acrylic surfaces using bursts of femtosecond laser pulses. By changing different laser parameters, it was possible to find a regime where the surface roughness can be minimized to 18 nm Ra, while the polishing of the entire part takes a matter of seconds. The produced surface demonstrates a transparent appearance and the process shows great promise towards commercial fabrication of low surface roughness custom-shape optics.

scholarly journals The role of heat effects in the process of formation of color centers in LiF during filamentation of femtosecond laser pulses

2019 ◽  
Vol 220 ◽  
pp. 02007
Author(s):  
A.V. Kuznetsov ◽  
V.P. Dresvyansky ◽  
O. Bukhtsoozh ◽  
S. Enkhbat ◽  
E.F. Martynovich
Keyword(s):  
Femtosecond Laser ◽  
Thermal Effects ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Color Centers ◽  
Heat Effects ◽  
Femtosecond Filamentation

The possibility of the influence of thermal effects on the formation of color centers during laser femtosecond filamentation in a LiF crystal has been investigated theoretically. The conditions are formulated under which the influence of thermal effects can be noticeable.

Surface Roughness and Crystallinity of Silicon Solar Cells Irradiated by Ultraviolet Femtosecond Laser Pulses

2020 ◽  
Vol 140 (8) ◽  
pp. 401-406
Author(s):  
Fumitaka Nigo ◽  
Masaki Hashida ◽  
Masahiro Tsukamoto ◽  
Shuji Sakabe ◽  
Mitsuhiro Kusaba
Keyword(s):  
Surface Roughness ◽  
Solar Cells ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Silicon Solar Cells
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