Effect of laser beam incidence angle on the thermoelastic generation in semi-transparent materials

2011 ◽  
Vol 130 (6) ◽  
pp. 3691-3697 ◽  
Author(s):  
Samuel Raetz ◽  
Thomas Dehoux ◽  
Bertrand Audoin
Keyword(s):  
Laser Beam ◽  
Incidence Angle ◽  
Beam Incidence ◽  
Transparent Materials ◽  
Thermoelastic Generation

Effect of laser beam incidence angle on cladding morphology in laser cladding process

2020 ◽  
Vol 34 (4) ◽  
pp. 1531-1537
Author(s):  
Guan Zhang ◽  
Wenlei Sun ◽  
Dongmei Zhao ◽  
Pengfei Fan ◽  
Feng Guo ◽  
...  
Keyword(s):  
Laser Beam ◽  
Laser Cladding ◽  
Incidence Angle ◽  
Laser Cladding Process ◽  
Beam Incidence

scholarly journals Expanding of Excimer Laser Photoablation’s Functionality in Ophthalmology

2021 ◽  
Vol 12 (3) ◽  
pp. 175-182
Author(s):  
V. A. Alekseev ◽  
V. G. Kostin ◽  
A. V. Usoltseva ◽  
V. P. Usoltsev ◽  
S. I. Yuran
Keyword(s):  
Laser Beam ◽  
Excimer Laser ◽  
Incidence Angle ◽  
A Priori ◽  
Laser Action ◽  
Ablation Zone ◽  
Corneal Surface ◽  
Vision Correction ◽  
Beam Incidence ◽  
Laser Vision

One of the significant weaknesses of excimer laser-based vision correction devices is the difficulty of achieving a required change in the refractive properties of the cornea to sharply focus the image on the retina with distance from the working area (ablation zone) center to the periphery due to a change in the laser beam incidence angle. The study is aimed at improving the quality of laser action on the eye cornea by introducing an optical corrective system into the existing excimer laser vision correction equipment, ensuring the coincidence of the direction of the laser beam incidence on the corneal surface with the normal.It has been shown that the greater the reflection coefficient, the lower the absorbed energy, and the shallower the laser radiation penetration and ablation depths, which reduces the laser action opportunities and quality. When using excimer laser vision correction devices, it has been proposed to change the angle of the laser beam incidence on the cornea with a distance from the working area (ablation zone) center to the periphery during the surgery by introducing an optical corrective system based on a lightweight controllable and movable mirror, which allows achieving the coincidence of the direction of the laser beam incidence on the corneal surface with the normal.The studies have shown that the coincidence of the laser beam incidence on the corneal surface at any point with the normal when using a priori data on the specifics of the patient's eye allows expanding the functional opportunities of excimer laser photoablation, i. e., expand the ablation zone by 30 % and eliminate the possibility of errors caused by the human factor. The technique proposed can be used for excimer laser vision correction according to PRK, LASIK, Femto-LASIK, and other methods. To implement this approach, a patented excimer laser vision correction unit has been proposed with a PCcontrolled optical shaping system comprising galvo motor platforms and galvo mirrors installed on them.

Influence of laser beam incidence angle on laser lap welding quality of galvanized steels

2017 ◽  
Vol 402 ◽  
pp. 147-158 ◽  
Author(s):  
Lifang Mei ◽  
Dongbing Yan ◽  
Genyu Chen ◽  
Zhenhui Wang ◽  
Shuixuan Chen
Keyword(s):  
Laser Beam ◽  
Incidence Angle ◽  
Welding Quality ◽  
Galvanized Steels ◽  
Beam Incidence ◽  
Laser Lap Welding ◽  
Lap Welding

Evaluation and defense of light commands attacks against voice controllable systems in smart cars

2021 ◽  
pp. 095745652110015
Author(s):  
Zhijian Xu ◽  
Guoming Zhang ◽  
Xiaoyu Ji ◽  
Wenyuan Xu
Keyword(s):  
Laser Beam ◽  
Success Rate ◽  
Incidence Angle ◽  
Attack Angle ◽  
Light Transmittance ◽  
Controllable System ◽  
Lower Light ◽  
Controllable Systems ◽  
Smart Cars ◽  
The Impact

The in-car voice controllable system has become an almost standard feature in smart cars. Prior work shows that the voice controllable system is vulnerable to light commands attack which uses the laser as the medium to inject voice commands. In this article, we first reproduced the light commands attack on acoustic isolated in-car voice controllable system under several scenarios with a lightweight solution. We validate the feasibility of injecting the malicious voice command through a window into the microphone by modulating a laser beam. Then, we tested a variety of mainstream countermeasures such as placing sunscreen film on the glass panel to see whether it can protect the microphone from being attacked. Surprisingly, we find that the lower light transmittance of sunscreen film is the lower the success rate of the attack. Experiment results also show that when the transmittance rate of sun film is 50% which is the darkest sunscreen film that can be applied, the attacking success rate decreased by up to 0.4. We also explore the impact of attack angle by changing the incidence angle of the laser beam and the results demonstrate that light commands is sensitive to attack angle and the successful angle range is ± 15°. Finally, we propose a series of hardware-based protection schemes against light commands attacks.

Dynamic ultrafast laser beam tailoring for multispot photo-inscription of photonic devices in bulk transparent materials

2009 ◽  
Author(s):  
C. Mauclair ◽  
G. Cheng ◽  
N. Huot ◽  
E. Audouard ◽  
A. Rosenfeld ◽  
...  
Keyword(s):  
Laser Beam ◽  
Photonic Devices ◽  
Ultrafast Laser ◽  
Transparent Materials

scholarly journals Formation and applications of periodic structures in transparent materials induced by single fs laser beam

2013 ◽  
Vol 3 (11) ◽  
pp. 1944 ◽  
Author(s):  
Fangteng Zhang ◽  
Yu Teng ◽  
Yongze Yu ◽  
Kaniyarakkal N. Sharafudeen ◽  
Kazuyuki Hirao ◽  
...  
Keyword(s):  
Laser Beam ◽  
Periodic Structures ◽  
Fs Laser ◽  
Transparent Materials
Sign in / Sign up

Export Citation Format

Share Document