scholarly journals New techniques for laser beam atmospheric extinction measurements from manned and unmanned aerospace vehicles

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Roberto Sabatini ◽  
Mark Richardson
Keyword(s):  
Laser Beam ◽  
Near Infrared ◽  
Laser Energy ◽  
Laser System ◽  
Direct Determination ◽  
Atmospheric Conditions ◽  
Atmospheric Extinction ◽  
Laser Systems ◽  
Non Linear Propagation ◽  
Nir Laser

AbstractNovel techniques for laser beam atmospheric extinction measurements, suitable for several air and space platform applications, are presented in this paper. Extinction measurements are essential to support the engineering development and the operational employment of a variety of aerospace electro-optical sensor systems, allowing calculation of the range performance attainable with such systems in current and likely future applications. Such applications include ranging, weaponry, Earth remote sensing and possible planetary exploration missions performed by satellites and unmanned flight vehicles. Unlike traditional LIDAR methods, the proposed techniques are based on measurements of the laser energy (intensity and spatial distribution) incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Various laser sources can be employed with wavelengths from the visible to the far infrared portions of the spectrum, allowing for data correlation and extended sensitivity. Errors affecting measurements performed using the proposed methods are discussed in the paper and algorithms are proposed that allow a direct determination of the atmospheric transmittance and spatial characteristics of the laser spot. These algorithms take into account a variety of linear and non-linear propagation effects. Finally, results are presented relative to some experimental activities performed to validate the proposed techniques. Particularly, data are presented relative to both ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ= 1064 nm and λ= 1550 nm. This includes ground tests performed with 10 Hz and 20 KHz PRF NIR laser systems in a large variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft.

WLCSP Laminate Removal Using NIR Laser

2018 ◽  
Author(s):  
Chun Haur Khoo
Keyword(s):  
Near Infrared ◽  
Laser Energy ◽  
Photon Emission ◽  
Mechanical Damage ◽  
Consumer Products ◽  
Fault Isolation ◽  
Wafer Level ◽  
Isolation Technique ◽  
Laminate Layer ◽  
Nir Laser

Abstract Driven by the cost reduction and miniaturization, Wafer Level Chip Scale Packaging (WLCSP) has experienced significant growth mainly driven by mobile consumer products. Depending on the customers or manufacturing needs, the bare silicon backside of the WLCSP may be covered with a backside laminate layer. In the failure analysis lab, in order to perform the die level backside fault isolation technique using Photon Emission Microscope (PEM) or Laser Signal Injection Microscope (LSIM), the backside laminate layer needs to be removed. Most of the time, this is done using the mechanical polishing method. This paper outlines the backside laminate removal method of WLCSP using a near infrared (NIR) laser that produces laser energy in the 1,064 nm range. This method significantly reduces the sample preparation time and also reduces the risk of mechanical damage as there is no application of mechanical force. This is an effective method for WLCSP mounted on a PCB board.

scholarly journals Short-wavelength experiments on laser pulse interaction with extended pre-plasma at the PALS-installation

2015 ◽  
Vol 34 (1) ◽  
pp. 94-108 ◽  
Author(s):  
T. Pisarczyk ◽  
S.Yu. Gus'kov ◽  
O. Renner ◽  
R. Dudzak ◽  
J. Dostal ◽  
...  
Keyword(s):  
Shock Wave ◽  
Energy Transfer ◽  
Laser Beam ◽  
Laser Energy ◽  
Laser System ◽  
Radiation Energy ◽  
Point Of View ◽  
Main Beam ◽  
Appreciable Effect ◽  
Fast Electrons

AbstractThe paper is a continuation of research carried out at Prague Asterix Laser System (PALS) related to the shock ignition (SI) approach in inertial fusion, which was carried out with use of 1ω main laser beam as the main beam generating a shock wave. Two-layer targets were used, consisting of Cu massive planar target coated with a thin polyethylene layer, which, in the case of two-beam irradiation geometry, simulate conditions related to the SI scenario. The investigations presented in this paper are related to the use of 3ω to create ablation pressure for high-power shock wave generation. The interferometric studies of the ablative plasma expansion, complemented by measurements of crater volumes and Kα emission, clearly demonstrate the effect of changing the incident laser intensity due to changing the focal radius on efficiency of laser energy transfer to a shock wave and fast electron emission. The efficiency of the energy transfer increases with the radius of the focused laser beam. The pre-plasma does not significantly change the character of this effect. However, it unambiguously results in the increasing temperature of fast electrons, the total energy of which remains very small (<0.1% of the laser energy). This study shows that the optimal radius from the point of view of 3ω radiation energy transfer to the shock wave is the maximal one used in these experiments and equal to 200 µm that corresponds to the minimal effect of two-dimensional (2D)-expansion. Such a result is typical for the ablation process determined by electron conductivity energy transfer under the conditions of one-dimensional or 2D matter expansion without any appreciable effect due to energy transfer by fast electrons. The 2D simulations based on application of the ALANT-HE code and an analytical model that includes generation and transport of hot electrons has been used to support of experimental data.

Monte Carlo Simulation of Enhanced Laser Absorption in Tumors With Gold Nanorod Injection

2011 ◽  
Author(s):  
Yonghui Chen ◽  
Ronghui Ma ◽  
Liang Zhu
Keyword(s):  
Gold Nanorods ◽  
Targeted Delivery ◽  
Near Infrared ◽  
Laser Energy ◽  
Gold Nanoshells ◽  
Surrounding Tissue ◽  
Laser Absorption ◽  
The Past ◽  
Tumor Region ◽  
Nir Laser

The employment of gold nanoshells or nanorods in photothermal emerges as a promising technology in treatment of cancers in the past several years [1–4]. Gold nanoshells consist of a solid dielectric core nanoparticle (∼100 nm) coated by a thin gold shell (∼10 nm). Gold nanorods are usually small with a size of ∼10 nm and an aspect ratio of approximately four. By varying the size ratio, the nanostructures can be tuned to have strong absorption and scattering to a specific near infrared (NIR) laser at ∼800 nm. The enhancement in laser energy absorption is several orders of magnitude compared to some traditional dyes [1]. The laser energy absorbed in an area congregating by the nanostructures is transferred to the surrounding tissue by heat conduction. The nanostructures in tumors not only enables targeted delivery of laser energy, but also maximally concentrates a majority of the laser energy to the tumor region.

Laser Induced Metal Deposition on Semiconductor, Metallic and Polymeric Substrates From Electroplating Solutions

1987 ◽  
Vol 101 ◽  
Author(s):  
J. Zahavi ◽  
S. Tamir ◽  
M. Rotel ◽  
G.J. Campisi ◽  
P.E. Pehrsson ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gallium Arsenide ◽  
High Speed ◽  
Laser Energy ◽  
Laser System ◽  
Pulsed Laser ◽  
Gold Deposits ◽  
Surface Barrier ◽  
Gold Cyanide ◽  
Laser Systems

ABSTRACTThis work is aimed at studying the feasibility of laser induced, high-speed, highly selective direct deposition of metals on substrates immersed in commercial electroplating solutions without masking procedures and external electric current.A Q-Switch Nd/YAG pulsed laser system and excimer UV pulsed laser systems operating respectively at wavelength of 532nm and at 193 and 248nm, were used in conjunction with commercial basic potassium gold cyanide and acidic gold tetrachloride solutions. The substrates were semiconductors (silicon, gallium arsenide and silicon carbide), metallic (platinum) and polymeric (polyimide).The morphology, structure, composition and properties of the gold deposits were examined by the SEM, TEM, X-ray, AES and ESCA techniques.Deposits were found to consist of elemental gold with thickness range from a few hundred angstroms to several micrometers, depending primarily on laser energy density and on the number of pulses. Deposition occurred wherever band gap energies (plus surface barrier) were smaller than the laser photon energy; none was observed in reverse situations, as in the cases of Si3N4 and fused SiO2.The deposits exhibited Schottky barrier contacts on silicon, silicon carbide and gallium arsenide.

Optical manipulation of individual strongly absorbing platinum nanoparticles

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18449-18455 ◽  
Author(s):  
Akbar Samadi ◽  
Poul Martin Bendix ◽  
Lene B. Oddershede
Keyword(s):  
Laser Beam ◽  
Platinum Nanoparticles ◽  
Near Infrared ◽  
Local Heating ◽  
Three Dimensions ◽  
Optical Manipulation ◽  
Optically Trapped ◽  
Nir Laser

Platinum nanoparticles have exceptional absorption in the near infrared (NIR) regime, thus leading to significant local heating. Nevertheless, they can be stably optically trapped in three dimensions by a tightly focused NIR laser beam.

scholarly journals High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from the NHELIX laser system at GSI

2005 ◽  
Vol 23 (4) ◽  
pp. 503-512 ◽  
Author(s):  
G. SCHAUMANN ◽  
M.S. SCHOLLMEIER ◽  
G. RODRIGUEZ-PRIETO ◽  
A. BLAZEVIC ◽  
E. BRAMBRINK ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Laser Energy ◽  
Laser System ◽  
Heavy Ion ◽  
Spot Size ◽  
High Energy ◽  
Focal Spot Size ◽  
Laser Systems ◽  
Order Of Magnitude ◽  
Long Pulse

High energy heavy ions were generated in laser produced plasma at moderate laser energy, with a large focal spot size of 0.5 mm diameter. The laser beam was provided by the 10 GW GSI-NHELIX laser systems, and the ions were observed spectroscopically in status nascendi with high spatial and spectral resolution. Due to the focal geometry, plasma jet was formed, containing high energy heavy ions. The velocity distribution was measured via an observation of Doppler shifted characteristic transition lines. The observed energy of up to 3 MeV of F-ions deviates by an order of magnitude from the well-known Gitomer (Gitomer et al., 1986) scaling, and agrees with the higher energies of relativistic self focusing.

scholarly journals Characterization of X-ray radiation from solid Sn target irradiated by femtosecond laser pulses in the presence of air plasma sparks

2016 ◽  
Vol 34 (3) ◽  
pp. 533-538 ◽  
Author(s):  
A. Curcio ◽  
M. Anania ◽  
F.G. Bisesto ◽  
A. Faenov ◽  
M. Ferrario ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Near Infrared ◽  
Laser Energy ◽  
Laser System ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
X Rays ◽  
Air Plasma ◽  
X Ray ◽  
Near Infrared Spectra

AbstractThe emission of X-rays from solid tin targets irradiated by low-energy (few mJ) femtosecond laser pulses propagated through air plasma sparks is investigated. The aim is that to better understand the X-ray emission mechanism and to show the possibility to produce proper radiation for spectroscopic and imaging applications with a table-top laser system. The utilization of a controlled ultrashort prepulse is found necessary to optimize the conversion efficiency of laser energy into Lα radiation. The optimum contrast between the main pulse and the controlled prepulse is found about 102. A correlation between the laser contrast value and the laser near-infrared spectra at the exit of the plasma spark is observed.

scholarly journals A Compact Micro-Bolometer Array for Mid-Infrared Laser Beam Alignment, Diagnostics and Spot-Size Measurement

2019 ◽  
Author(s):  
Ian Clark ◽  
Michael Towrie
Keyword(s):  
Laser Beam ◽  
Near Infrared ◽  
Focal Point ◽  
Laser System ◽  
Spot Size ◽  
Infrared Laser ◽  
Pixel Size ◽  
Mid Infrared ◽  
Bolometer Array ◽  
Infrared Laser Beam

Knowledge of a lasers beam&rsquo;s profile throughout a laser system and experiment can help immensely in diagnosing laser problems and assisting in beam alignment and focusing at a sample. Obtaining such profiles is a trivial task in the ultraviolet-visible wavelength range but more challenging with near-infrared to infrared beams. Scientific grade bolometer arrays, suitable for such a task, do exist but are extremely costly, relatively large and have a large pixel size, of the order of 80 &mu;m, which is adequate for profiling larger beams but poses an issue when trying to profile sub 100 &mu;m beams for example at a focal point. This communication identifies a micro-bolometer array for near- to mid-infrared laser beam profiling, which is extremely low cost. In addition, the device is very compact, enabling use in confined spaces, and has a small, 12 &mu;m, pixel size permitting the profiling of focused laser beams. The best scientific grade device identified has a pixel size of 17 &mu;m. This device is a powerful tool for infrared laser spectroscopists, reducing the time required to measure the spot size of beams and to achieve spatial overlap of multiple infrared beams as used in two-dimensional infrared spectroscopy, saving many hours of setup time. The use of the bolometer array as a spectrographic detector and probe of long-term beam drifts is also demonstrated.

scholarly journals REDUCING RISK FACTORS IN THE WORKPLACE OF THE LASER SYSTEM OPERATOR

2019 ◽  
Vol 3 ◽  
pp. 184
Author(s):  
Pāvels Narica ◽  
Inese Martinsone
Keyword(s):  
Risk Factors ◽  
Laser Beam ◽  
Thermal Effects ◽  
Laser Processing ◽  
Laser System ◽  
Production Processes ◽  
System Operator ◽  
Laser Systems ◽  
Harmful Substances

Laser processing of materials takes an increasing place in production processes. Improving the performance, improving the quality of processing is not a complete list of the positive aspects of the introduction of laser processing, but there are a number of points that need to be paid attention to during the operation of laser systems - these are issues related to safety. The following risk factors are specific to laser systems: firstly, the laser beam itself, effects on the organs of vision, direct thermal effects on the skin and tissues, secondly, harmful products resulting from the interaction of the laser beam and the material being processed. Aerosols, smoke and dust have different effects on the human body, especially on the respiratory system and the publication considers the risks associated with the release of harmful products during laser processing and the existing methods for reducing the concentration of harmful substances in the working area with specific examples.

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