scholarly journals Femtosecond laser-induced damage threshold in snow micro-structured targets

2018 ◽  
Vol 6 ◽  
Author(s):  
O. Shavit ◽  
Y. Ferber ◽  
J. Papeer ◽  
E. Schleifer ◽  
M. Botton ◽  
...  
Keyword(s):  
Laser Energy ◽  
Local Density ◽  
Damage Threshold ◽  
Laser Pulses ◽  
High Energy ◽  
Hot Electron ◽  
Short Laser Pulses ◽  
Laser Induced Damage ◽  
Pulse Structure ◽  
Positively Charged

Enhanced acceleration of protons to high energy by relatively modest high power ultra-short laser pulses, interacting with snow micro-structured targets was recently proposed. A notably increased proton energy was attributed to a combination of several mechanisms such as localized enhancement of the laser field intensity near the tip of $1~\unicode[STIX]{x03BC}\text{m}$ size whisker and increase in the hot electron concentration near the tip. Moreover, the use of mass-limited target prevents undesirable spread of absorbed laser energy out of the interaction zone. With increasing laser intensity a Coulomb explosion of the positively charged whisker will occur. All these mechanisms are functions of the local density profile and strongly depend on the laser pre-pulse structure. To clarify the effect of the pre-pulse on the state of the snow micro-structured target at the time of interaction with the main pulse, we measured the optical damage threshold (ODT) of the snow targets. ODT of $0.4~\text{J}/\text{cm}^{2}$ was measured by irradiating snow micro-structured targets with 50 fs duration pulses of Ti:Sapphire laser.

scholarly journals SSD detection on LIDT tested coated Fused Silica samples

2021 ◽  
Vol 255 ◽  
pp. 03009
Author(s):  
Heidi Cattaneo ◽  
Daniel Schachtler ◽  
Roelene Botha ◽  
Oliver Fähnle
Keyword(s):  
Laser Energy ◽  
Substrate Surface ◽  
Single Layer ◽  
Damage Threshold ◽  
Surface Damage ◽  
Laser Pulses ◽  
Fused Silica ◽  
Small Surface ◽  
Additional Information ◽  
Laser Induced Damage

Material changes and Sub-Surface Damage (SSD) under Laser Induced Damage Threshold (LIDT) testing sites were investigated on 3 diverse single layer coated transparent fused silica samples to obtain additional information on damage precursors on these samples. As a detection method, photothermal deflection technique utilizing a resonant UV laser beam was used. The local variations in UV absorption and probe beam transmittance due to previous exposure to high fluence laser pulses were strongly dependent on the coating itself and on the laser energy used during the LIDT testing. Also the obtained LIDT values differ from coating to coating. Detected effects on the coatings and substrate surface beneath ranged from small surface dislocations to complete coating damage with material transformations. Additional absorbing damage precursors were found close to the damaged sites.

Acoustic Method of Detection of Optical Thin Films Damage

2011 ◽  
Vol 301-303 ◽  
pp. 965-969
Author(s):  
Yi Ding ◽  
Jun Hong Su ◽  
Hai Feng Liang
Keyword(s):  
Thin Films ◽  
Laser Energy ◽  
Damage Threshold ◽  
Acoustic Method ◽  
High Energy ◽  
Laser Damage Threshold ◽  
Image Method ◽  
Sound Waves ◽  
Optical Films ◽  
Laser Induced Damage

Laser damage threshold of optical thin film is a critical parameter in measuring laser induced damage. The key to testing damage threshold is judging the injury incident accurately. It has been found that when high-energy laser on the film, there will be sounds generated. In the present paper, acoustic method was applied to determine thin films damage. A brief analysis will be given on feasibility of acoustic method in judging thin films damage. Acoustic acquisition system will be established. In the experiment, we will average laser energy into 10 grades, each grade test 10 points. The sound wave of each point will be record. At the same time, we use image method judge damage of the thin films and record the result. By studying the sound waves of the thin films in different laser energy，it is easy to judge whether the optical films is damaged. The measured result is compared with image method. Both of them have a preferable consistency. The analysis shows that the acoustic method can be used effectively to determine laser-induced damage and it can be used in online inspection conveniently.

scholarly journals High laser induced damage threshold photoresists for nano-imprint and 3D multi-photon lithography

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Elmina Kabouraki ◽  
Vasileia Melissinaki ◽  
Amit Yadav ◽  
Andrius Melninkaitis ◽  
Konstantina Tourlouki ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Three Dimensional ◽  
Damage Threshold ◽  
Laser Pulses ◽  
Intense Laser ◽  
Optical Elements ◽  
Photonic Circuits ◽  
Future Production ◽  
Intense Laser Pulses ◽  
Laser Induced Damage

Abstract Optics manufacturing technology is predicted to play a major role in the future production of integrated photonic circuits. One of the major drawbacks in the realization of photonic circuits is the damage of optical materials by intense laser pulses. Here, we report on the preparation of a series of organic–inorganic hybrid photoresists that exhibit enhanced laser-induced damage threshold. These photoresists showed to be candidates for the fabrication of micro-optical elements (MOEs) using three-dimensional multiphoton lithography. Moreover, they demonstrate pattern ability by nanoimprint lithography, making them suitable for future mass production of MOEs.

scholarly journals Laser-induced damage thresholds of ultrathin targets and their constraint on laser contrast in laser-driven ion acceleration experiments

2020 ◽  
Vol 8 ◽  
Author(s):  
Dahui Wang ◽  
Yinren Shou ◽  
Pengjie Wang ◽  
Jianbo Liu ◽  
Zhusong Mei ◽  
...  
Keyword(s):  
Damage Threshold ◽  
Wide Band ◽  
Laser Pulses ◽  
Laser Damage Threshold ◽  
Single Shot ◽  
Bulk Materials ◽  
Free Standing ◽  
Wide Band Gap ◽  
Different Types ◽  
Laser Induced Damage

Abstract Single-shot laser-induced damage threshold (LIDT) measurements of multi-type free-standing ultrathin foils were performed in a vacuum environment for 800 nm laser pulses with durations τ ranging from 50 fs to 200 ps. The results show that the laser damage threshold fluences (DTFs) of the ultrathin foils are significantly lower than those of corresponding bulk materials. Wide band gap dielectric targets such as SiN and formvar have larger DTFs than semiconductive and conductive targets by 1–3 orders of magnitude depending on the pulse duration. The damage mechanisms for different types of targets are studied. Based on the measurement, the constrain of the LIDTs on the laser contrast is discussed.

scholarly journals Laser-Induced Point Defects in Fused Silica Irradiated by UV Laser in Vacuum

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoyan Zhou ◽  
Xinda Zhou ◽  
Jin Huang ◽  
Qiang Cheng ◽  
Fengrui Wang ◽  
...  
Keyword(s):  
Point Defects ◽  
Fluorescence Spectra ◽  
Uv Spectroscopy ◽  
Damage Threshold ◽  
Laser Pulses ◽  
Fused Silica ◽  
Third Harmonic ◽  
Structural Modifications ◽  
Laser Induced Damage ◽  
Induced Defects

High-purity fused silica irradiated by third harmonic of the Nd:YAG laser in vacuum with different laser pulse parameters was studied experimentally. Laser-induced defects are investigated by UV spectroscopy, and fluorescence spectra and correlated to the structural modifications in the glass matrix through Raman spectroscopy. Results show that, for laser fluence below laser-induced damage threshold (LIDT), the absorbance and intensity of fluorescence bands increase with laser energies and/or number of laser pulses, which indicates that laser-induced defects are enhanced by laser energies and/or number of laser pulses in vacuum. The optical properties of these point defects were discussed in detail.

scholarly journals Transport of hot electron currents in solid targets irradiated by high intensity short laser pulses

2010 ◽  
Vol 244 (2) ◽  
pp. 022016 ◽  
Author(s):  
P Antici ◽  
P Audebert ◽  
M Borghesi ◽  
T Cowan ◽  
L Gremillet ◽  
...  
Keyword(s):  
High Intensity ◽  
Laser Pulses ◽  
Hot Electron ◽  
Short Laser Pulses

INFLUENCE OF DEPOSITION TEMPERATURE ON OPTICAL AND LASER-INDUCED DAMAGE PROPERTIES OF LaTiO3 FILMS

2015 ◽  
Vol 22 (06) ◽  
pp. 1550070 ◽  
Author(s):  
JUNHONG SU ◽  
JUNQI XU ◽  
CHEN YANG ◽  
YAOJIN CHENG
Keyword(s):  
Pulse Width ◽  
Deposition Temperature ◽  
Room Temperature ◽  
Damage Threshold ◽  
High Energy ◽  
Vapor Deposition Technique ◽  
Different Temperatures ◽  
Thermal Vapor Deposition ◽  
Laser Induced Damage ◽  
The Relationship

LaTiO 3 films were prepared at room temperature, 60, 140 and 220°C using a thermal vapor deposition technique with an electronic beam gun to investigate the relationship between deposition temperatures and the optical properties of the samples. In the ellipsometric analysis, the corresponding refractive indexes were 1.8993, 1.9123, 1.9197 and 1.9283 at a wavelength of 1064 nm. At the same time, extremely low absorption characteristics of all the samples presented in the visible and IR regions. With the same high-energy testing laser of 200 mJ (about 40 J/cm2) at a wavelength of 1064 nm and a pulse width of 10 ns, the laser-induced damage threshold (LIDT) of the LaTiO 3 samples prepared at different temperatures were 15.5, 16.7, 18.5 and 18.2 J/cm2, respectively. This shows that a higher LIDT may be obtained at higher deposition temperatures.

scholarly journals Accelerating ions with high-energy short laser pulses from submicrometer thick targets

2016 ◽  
Vol 4 ◽  
Author(s):  
F. Wagner ◽  
C. Brabetz ◽  
O. Deppert ◽  
M. Roth ◽  
T. Stöhlker ◽  
...  
Keyword(s):  
Focal Plane ◽  
Short Pulse ◽  
Laser Pulses ◽  
High Energy ◽  
Ion Acceleration ◽  
Temporal Contrast ◽  
Short Pulse Laser ◽  
Target Intensity ◽  
Short Laser Pulses ◽  
And Control

Using the example of the PHELIX high-energy short pulse laser we discuss the technical preconditions to investigate ion acceleration with submicrometer thick targets. We show how the temporal contrast of this system was improved to prevent pre-ionization of such targets on the nanosecond timescale. Furthermore the influence of typical fluctuations or uncertainties of the on-target intensity on ion acceleration experiments is discussed. We report how these uncertainties were reduced by improving the assessment and control of the on-shot intensity and by optimizing the positioning of the target into the focal plane. Finally we report on experimental results showing maximum proton energies in excess of 85 MeV for ion acceleration via the target normal sheath acceleration mechanism using target thicknesses on the order of one micrometer.

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