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Conference 12300
Laser-Induced Damage in Optical Materials 2022
18 - 21 September 2022 | Meeting Room A/B
Conference Co-Sponsor
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Laser Damage Tutorial and Discussion
18 September 2022 • 6:00 PM - 7:00 PM PDT
Session Chair:
Michael D. Thomas, Spica Technologies, Inc. (United States)
PC12300-501
18 September 2022 • 6:00 PM - 7:00 PM PDT
Show Abstract +
This talk will address the history of laser damage testing and how early measurement techniques have given way to current best practices and the development of those best practices across multiple wavelength ranges. The talk will discuss current methodologies, which have been driven by the development of the laser marketplace and the need for manufacturers and end users to qualify and assure components will meet the laser damage needs at the system level. The talk will conclude with novel measurement techniques and the direction of future work supporting the growth of laser technologies.
Opening Remarks
19 September 2022 • 8:00 AM - 8:20 AM PDT
Carmen Menoni, Colorado State Univ. (United States)
Session 1:
Materials and Measurements I
19 September 2022 • 8:20 AM - 10:10 AM PDT
Session Chairs:
Stavros G. Demos, Univ. of Rochester (United States), Chloé Lacombe, CEA-Cesta (France)
12300-1
1077-nm, CW mirror thin film damage competition
(Keynote Presentation)
On demand | Presented live 19 September 2022
Show Abstract +
We propose to survey the state-of-the-art of CW, near-IR high reflectors. Specifically, mirrors must meet a minimum reflection of 99.5% at normal incidence for 1064 nm. The participants select the coating materials, design, and deposition method. The samples will be damage tested using a kW fiber laser system capable of delivering up to 16 MW/cm2 irradiance on target at a single testing facility to enable direct comparison among the participants. Details of the deposition processes, cleaning method, coating materials, and layer count will be shared.
12300-2
On demand | Presented live 19 September 2022
Show Abstract +
Laser-Induced Deep Etching (LIDE) is considered as the one of the most promising techniques for production of so-called TGVs (Through Glass Vias). In the production process, thin glass sheet is treated with ultra-short lasers pulses to induce surface and volume modification, allowing efficient wet etching and formation of through hole. Precise knowledge of damage threshold of such glass is essential when optimizing the whole process and scaling up the production via laser beam parallelization. In following paper, we present recent results on LIDT measurement of D263 glass sheets at wavelengths 1030 nm and 515 nm, effective utilization of such knowledge for setting up multi-Bessel beam processing optics, and we demonstrate resulting substrates with TGVs.
PC12300-69
19 September 2022 • 9:10 AM - 9:30 AM PDT
Show Abstract +
Remote sensing, range finding, optical communications have strong demand for compact, eye-safe lasers. Co2+:MgAl2O4 crystals can be used as a passive Q-switchers to obtain pulses of compact Er:glass lasers and might be one of the limiting factors, determining their maximum output power. This study presents oxygen plasma etching of commercially-polished Co2+:MgAl2O4 crystals, including investigation on their spectrophotometric, surface and LIDT (R(1)-on-1) properties using two different lasers and beam diameters - 172 µm and 55 µm at 1540 nm. Measurements higher fluence laser and smaller 55 µm laser beam diameter allowed determination of all etched crystals and revealed dramatic increase of their surface LIDT comparing to untreated sample.
PC12300-4
19 September 2022 • 9:30 AM - 9:50 AM PDT
Show Abstract +
The MELBA testbed located at CEA CESTA (France) is a nanosecond UV centimeter-sized beam aiming at studying laser damage. Previous work carried out on MELBA showed a dependency of laser-induced damage to power modulation of the laser pulse in linear propagation regime. We extended this study to the non-linear propagation regime. Thanks to dedicated imaging setup, we carried out an experimental study of Bespalov-Talanov gain and laser-induced damage with different temporal modulations. The tuning of phase modulation parameters made it possible to annihilate backward stimulated Brillouin scattering and consequently focus on the impact of the Kerr effect.
12300-5
On demand | Presented live 19 September 2022
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We present a novel damage mitigation technique suitable for arresting the laser-induced growth of 1-2 mm damage sites on the exit of SiO2 optics by placing a CO2 machined cone on the input surface which shadows the damage. Considerations for design and fabrication will be presented with results from intensity measurements and laser induced damage experiments. The results show a significant dependence of damage resistance on the polarization state of the machining CO2 laser.
Poster Slams: Materials and Measurements I
19 September 2022 • 10:10 AM - 10:40 AM PDT
Session Chairs:
Detlev Ristau, Laser Zentrum Hannover e.V. (Germany), MJ Soileau, CREOL, The College of Optics and Photonics, Univ. of Central Florida (United States)
Join the poster presenters of the Materials and Measurements I session for their two-minute oral slams. Each poster author is invited to give a brief (two-minute) preview of their research with a maximum of three slides during this poster slam session.
Poster authors: bring your slides on a USB drive to the session and be prepared to give a short summary of your poster.
The posters will be available for viewing at the Poster Session immediately following the poster slams.
View Poster Slam Schedule
View Poster Slam Schedule
Poster Session: Materials and Measurements I
19 September 2022 • 10:40 AM - 11:40 AM PDT | Meeting Room C
After the poster slam conference attendees are invited to attend the Materials and Measurements I poster session on Monday morning. Come view the posters, enjoy some coffee or tea, ask questions, and network with colleagues in your field.
Poster Setup: Monday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
Poster Setup: Monday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
PC12300-43
On demand | Presented live 19 September 2022
Show Abstract +
Nematic liquid crystals (LC’s) are transparent rod-shaped molecules that can exhibit large dielectric anisotropy, high birefringence, and excellent transparency, which make them well suited for use in many optical components in high power laser systems and, potentially, within hybridized metamaterials. One LC optimized by our group was evaluated in this study, in which we investigated the impact of nematic LC material optimization on laser damage, electro-optical switching, and operational lifetime of laser beam manipulation devices at 1053 nm and average power densities in the kW/cm2 regime at 10- to 40-Hz repetition rates.
This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856, the University of Rochester, and the New York State Energy Research and Development Authority.
PC12300-44
On demand | Presented live 19 September 2022
Show Abstract +
High energy laser facilities designed for fusion experiments, such as Laser MegaJoule or National Ignition Facility, are limited by laser-induced damage on their final optics. Accurate and early detection of damage growth is required for successful operation of such facilities. Since the image resolution is about the size of damage sites to monitor, diameter measurements are not sufficient to meet the objectives of damage growth quantification. To accurately assess damage growth, a method based on Digital Image Correlation is proposed. Optical simulations and laser damage experiments on a highly instrumented set-up were performed to evaluate the performance of the proposed method.
12300-45
On demand | Presented live 19 September 2022
Show Abstract +
Absorptance is often considered a static feature of an optical element that is determined via standardized measurement procedures. Although such measurements are often performed using optical instruments with low light intensity, in high power laser applications irradiation conditions are considerably different. Optics might become unstable due to highly intense light: optical properties change in a nonlinear way and might eventually lead to laser-induced damage. To study these effects we employed the common-path interferometry technique in combination with a high energy and high average power laser source, delivering 10 ps pulses at 355 nm wavelength. We investigated an AR@355 nm coating deposited using ion beam sputtering on a lithium triborate crystal. Our preliminary results indicate both strong nonlinear absorptance and fatigue near the damaging fluence, however, damage events were not directly related to the critical absorptance level.
PC12300-46
19 September 2022 • 10:40 AM - 11:40 AM PDT | Meeting Room C
Show Abstract +
A “cumulative” algorithm has recently been proposed as an alternative to the widely used International Organization for Standardization (ISO) standard approach to analyze laser-induced‒damage testing data. This algorithm may be particularly suitable for situations where the available sampling is limited. This work discusses the advantages and limitations of the cumulative algorithm using both simulated data and analytical models. Although the algorithm aims to increase statistical confidence for a given data set, it is demonstrated that the retrieved damage-probability distribution inaccurately represents the true distribution, even for a perfect measurement with infinite sampling. Modified versions of the cumulative algorithm are explored in attempt to increase accuracy.
PC12300-47
On demand | Presented live 19 September 2022
Show Abstract +
The poster will present MELBA, an experimental setup which provides a 4J ultraviolet (351 nm) centimeter-sized beam dedicated to the study of laser-induced damage and damage growth in the context of ICF lasers. To this end, spatial, temporal and spectral characteristics of the laser beam can all be adjusted. Associated high-end spatial, temporal and spectral diagnostics are available to characterize the laser beam at 351nm. As of today, dedicated imaging systems were set up to assess the impact of non-linear propagation on laser-induced damage and filamentation formation.
12300-48
On demand | Presented live 19 September 2022
Show Abstract +
Subsurface damage (SSD) in optical components is almost unavoidably caused by mechanical forces involved during grinding and polishing and can be a limiting factor, particularly for applications that require high laser powers.
In this contribution, different non-destructive characterization techniques such as angle-resolved light scattering, local absolute absorption, and ellipsometry are evaluated with respect to their capabilities to determine SSD in fused silica. These results are compared to a destructive analysis using etching in hydrofluoric acid in combination with white light interferometry. Laser-induced damage tests are performed to determine the impact of SSD on the damage probability.
PC12300-70
On demand | Presented live 19 September 2022
Show Abstract +
We report on the laser-damage threshold of common liquid crystal alignment materials, including rubbed polyimide, rubbed nylon, and a photoaligned azobenzene. The photoaligned azobenzene is, in principle, more laser-damage resistant because of the no-touch processing in the clear aperture with the added benefit of ease of scaling and processing. We compare the polarization dependence of the damage threshold with respect to the alignment direction in ordinary and extraordinary modes at a near-infrared wavelength. Laser-damage thresholds depend substantially on the presence of aligned liquid crystal materials. We also compare laser-damage–threshold dependence on the electrical actuation state of the nematic liquid crystal material. These data inform design of high-power beam-shaping devices for applications in fusion, 3-D printing, and defense systems.
Break
Lunch Break 11:40 AM - 1:10 PM
Session 2:
Materials and Measurements II
19 September 2022 • 1:10 PM - 2:30 PM PDT
Session Chairs:
Raluca A. Negres, Lawrence Livermore National Lab. (United States), Jan Vanda, HiLASE Ctr. (Czech Republic)
12300-6
On demand | Presented live 19 September 2022
Show Abstract +
Laser processing is useful for topographical and band structure modification of semiconductors. We used a Scanning Tunneling Microscope (STM) to map topography of silicon (100) damaged with an ultrafast pulsed
Yb:KGW laser at 1030 nm with duration of 70 fs in high vacuum. In particular we observed periodic surface structures (λ/10 ≈ 100 nm spacing). dI/dV spectra can be combined with topography to understand the laser damage process better and eventually can be used to characterize defect formation without the presence of topographical change.
PC12300-7
Real-time dynamics of diamond Bulk micro-explosion induced by ultrashort high intensity single pulse
19 September 2022 • 1:30 PM - 1:50 PM PDT
Show Abstract +
Ultrafast dynamics of ultrashort single pulse induced micro-explosions in bulk Diamond was examined using time resolved shadowgraphy technique in a pump-probe experimental setup. Experimental and theoretical considerations identify such confined micro-explosions creating Warm Dense Matter (WDM) state. Different phases of the ongoing micro-explosions have been captured in real-time with femtoseconds to picoseconds temporal and micron-sized spatial resolutions. This study broadens the horizon of our understanding of exotic matter generation process in extreme environments.
PC12300-8
19 September 2022 • 1:50 PM - 2:10 PM PDT
Show Abstract +
Cathodoluminescence and electrostatic techniques were used to study the nanoscale spatial evolution of native defects, crystallinity and work function in Ga2O3 across different morphological regions in laser induced periodic surface structures generated by an ultrafast laser. An emergent ~2.4 eV emission, likely related to oxygen interstitials or divacancy complexes, inversely correlates with the crystallinity of these regions. A contrast in work functions between the rims and troughs of the LIPSS, indicative of periodic differences in defect concentration, correlates with a reduction of crystallinity in the rim region relative to the trough region, suggesting an increased concentration of relatively shallow defects.
PC12300-9
19 September 2022 • 2:10 PM - 2:30 PM PDT
Show Abstract +
Laser MegaJoule (LMJ) is a high energy laser facility designed for fusion experiments. To track final optics damage, laser damage monitoring is carried out using images acquired by a camera. To prepare for the LMJ full energy/power operation, the damage models based on the phenomenological laws established in the laboratories are validated by experimental campaigns dedicated to performance. The very high quality of LMJ optics surfaces makes damage highly unlikely. In order to take the greater benefit of these performance campaigns, carried out on a reduced number of laser shots and components, a matrix of nearly 1000 damage sites is initiated offline on one optics. Precisely measured on a metrology bench before and after the campaign, this component was on LMJ facility during a performance campaign at the end of 2021. Very useful for the calibration of the LMJ monitoring camera, it also provided data to set LMJ laser damage models at higher energy level.
Poster Slams: Materials and Measurements II
19 September 2022 • 2:30 PM - 3:00 PM PDT
Session Chairs:
Detlev Ristau, Laser Zentrum Hannover e.V. (Germany), MJ Soileau, CREOL, The College of Optics and Photonics, Univ. of Central Florida (United States)
Join the poster presenters of the Materials and Measurements II session for their two-minute oral slams. Each poster author is invited to give a brief (two-minute) preview of their research with a maximum of three slides during this poster slam session.
Poster authors: bring your slides on a USB drive to the session and be prepared to give a short summary of your poster.
The posters will be available for viewing at the Poster Session immediately following the poster slams.
View Poster Slam Schedule
View Poster Slam Schedule
Poster Session: Materials and Measurements II
19 September 2022 • 3:00 PM - 4:00 PM PDT | Meeting Room C
After the poster slam conference attendees are invited to attend the Materials and Measurements II poster session on Monday afternoon. Come view the posters, enjoy some coffee or tea, ask questions, and network with colleagues in your field.
Poster Setup: Monday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
Poster Setup: Monday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
12300-49
On demand | Presented live 19 September 2022
Show Abstract +
This article is focused on the design of a beam delivery system based on hollow-core photonic crystal fiber. The first part of the article is a brief introduction to PERLA 100, the laser used for testing the efficiency of the beam delivery system developed by HiLASE Centre. The reader will be acquainted with the laser system parameters. The input beam parameters play an important role in the efficiency of focusing into the fiber. One of the key parameters is the M2 of the beam, as it has a direct effect on the size of the waist at the point of entry into the fiber. Another important parameter is the maximum energy in one pulse which can destroy the fiber structure. The article aims to eliminate as many critical points as possible when setting up a focusing system and thus prevent damage to the fiber structure. The aim is to achieve a coupling efficiency of more than 90 % by scaling the PERLA 100 output power from units of W up to 100 W.
PC12300-50
On demand | Presented live 19 September 2022
Show Abstract +
A measurement concept is introduced that allows the characterization of round shaped sample geometries with a thickness of up to 10mm by means of the laser induced deflection (LID) technique for direct and absolute absorption measurement.
A series of TiO2 and HfO2 single layers has been investigated with respect to their nonlinear absorption at 800 nm and 400 nm, respectively, using a high intensity fs-laser and its second harmonic. TiO2 thin film absorption at 800 nm shows the expected linear increase with laser intensity indicating a two-photon absorption process. In contrast, nonlinear absorption in HfO2 thin films at 400 nm revealed a sublinear increase with laser intensity that was verified by measurements using a high intense ns-laser at 355 nm.
The nonlinear absorption properties have been compared to theoretical models showing a good agreement at least for the TiO2 two-photon absorption coefficient.
PC12300-51
On demand | Presented live 19 September 2022
Show Abstract +
In this study, ~2500 surface damage sites associated with filaments (SDWF) as small as 10µm in diameter are identified and imaged with high-resolution optical microscopy in several WFLs with various densities of filamentary damage. Repairs were attempted on a subset of the SDWF and the outcome reimaged. Subsequent to repair, these WFLs were installed on NIF for at least one laser shot above 9 J/cm2 at 351 nm. Once removed from NIF, both the repaired and unrepaired SDWF were evaluated for growth. The probability of growth of SDWF that breached the surface 1) by prior laser exposure and 2) as a result of repair were measured. The results suggest that, of the surface damage associated with filaments (SDWF), those with a single filament do not grow after being repaired, while repair of densely clustered filaments can induce growth.
PC12300-52
19 September 2022 • 3:00 PM - 4:00 PM PDT | Meeting Room C
Show Abstract +
The current progress in the drones has been increasing
the threat for public and society. Specially, the anti-jammers that
have already been installed on the drones, have made the counter
for jammers. The need of directed energy weapon is fed in this
regard. High powered laser is one of the type of directed energy
weapon in which laser intensity is focused on the target. The laser
that will be using is 10 W blue laser( λ = 450nm). Although, it
is not powered enough to burn out the drone but it can damage
the payload(EO/IR) of drone. A digital electro-optic sensor is also
being tested on the lasers and the pixels have been destroyed within
a few seconds. The main aim of drones is reconnaissance with the
help of cameras or some IR sensors. So the goal is to damage these
sensors or destroy the pixels of drone camera with the help of lasers.
The better effects have been achieved by the concept of combination
of lasers.
PC12300-53
On demand | Presented live 19 September 2022
Show Abstract +
Incubation of defects is thought to cause the reduction of the laser-induced damage threshold (LIDT) as the number of pulses increases (until a saturation point). We present a novel way to detect sub-LIDT defects in wide bandgap semiconductors by using Kelvin Probe Force Microscopy (KPFM), where a bias is applied between a conductive KPFM tip and sample while scanning. S-on-1, multi-pulse LIDT experiments at wavelength 1030-nm and pulse duration 96-fs were performed on single-crystal β-gallium oxide and silicon carbide. Analysis with KPFM revealed that the work function was altered in irradiated areas (fluence below LIDT) even when sites appeared undamaged.
12300-54
On demand | Presented live 19 September 2022
Show Abstract +
The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solid-state 266-nm pulsed Nd:YAG laser to perform compositional analysis on the surface of Titan. Due to the high fluence of the focused pulse energy on the laser’s beam steering unit (BSU) and the mass spectrometer window, the damage threshold of these optics in a Titan atmosphere needed to be characterized. This paper details the test setup and the successful demonstration of testing the highest fluence optics for the expected mission duration of 2 million laser pulses in a Titan-relevant atmosphere.
Session 3:
Materials and Measurements III
19 September 2022 • 4:00 PM - 5:20 PM PDT
Session Chairs:
Enam A. Chowdhury, The Ohio State Univ. (United States), Simin Zhang, The Ohio State Univ. (United States)
PC12300-10
19 September 2022 • 4:00 PM - 4:20 PM PDT
Show Abstract +
High energy laser facilities designed for fusion experiments, such as Laser MegaJoule or National Ignition Facility, are limited by laser-induced damage on their final optics. Accurate and early detection of damage growth is required for successful operation of such facilities. Since the image resolution is about the size of damage sites to monitor, diameter measurements are not sufficient to meet the objectives of damage growth quantification. An accurate size quantification of damage sites is based on light scattering measurements after time-consuming calibrations on the facility. An optical model is proposed to perform a simple and fast calibration of the measurements by numerical simulation. The model is based on light scattering measurements of several damage sites combined with optical simulations of the lighting system.
12300-11
On demand | Presented live 19 September 2022
Show Abstract +
For laser induced damage testing (LIDT), knowing the spatial and temporal properties of the laser beam is critically important. Therefore, it is necessary to monitor the laser beam profile continuously or at least periodically during the laser operation. One reason for measuring the laser beam profile frequently is that commonly in industrial or scientific applications, a laser is pushed to its operations limit causing change to the laser beam profile.
We developed a low reflective beam splitter (BS) for hot-spot monitoring of argon-fluoride (ArF) laser, and detected hot-spot in a laser beam profile only at high discharge current and high output power mode.
12300-12
On demand | Presented live 19 September 2022
Show Abstract +
Identifying laser induced damage on the surface of optical components for the purpose of tracking its growth
over time and repairing it is an important part of the economical operation of the National Ignition Facility
(NIF). Optics installed on NIF are monitored in situ for damage growth and can be removed as needed for
repair and re-use. An ex-situ automated microscopy system is used to inspect full sized NIF optics allowing
for the detection of damage sites >10 µm in diameter. Due to the various morphology of laser damage,
several algorithms are used to analyze the microscopy data and identify damage regardless of size, while
ignoring features not related to laser damage. This system has significantly increased the lifetime of NIF
final optics (∼2.3x) thereby extending beyond the capabilities of the in-situ inspection by itself.
PC12300-13
19 September 2022 • 5:00 PM - 5:20 PM PDT
Show Abstract +
We investigate fluid jet polishing (FJP) for its potential to be used for freeform finishing of fused silica and potassium dihydrogen phosphate (KDP and DKDP) crystals without compromising laser damage performance. As part of this effort, a different slurry for each material was utilized. Samples with different amounts of material removed by FJP were prepared for damage testing. The results show that FJP can improve or maintain the laser damage resistance of these materials while simultaneously functioning as a deterministic, sub-aperture finishing method.
Closing Remarks
19 September 2022 • 5:20 PM - 5:30 PM PDT
Detlev Ristau, Laser Zentrum Hannover e.V. (Germany)
Opening Remarks
20 September 2022 • 8:00 AM - 8:20 AM PDT
Eyal Feigenbaum, Lawrence Livermore National Lab. (United States)
Session 4:
Mini-Symposium on Application of Metasurface Optics for use with High-Power Lasers I
20 September 2022 • 8:20 AM - 10:10 AM PDT
Session Chairs:
Eyal Feigenbaum, Lawrence Livermore National Lab. (United States), Jonathan Phillips, STFC Rutherford Appleton Lab. (United Kingdom)
PC12300-14
Actively tunable metasurfaces for high power applications
(Keynote Presentation)
20 September 2022 • 8:20 AM - 8:50 AM PDT
PC12300-15
20 September 2022 • 8:50 AM - 9:10 AM PDT
Show Abstract +
We investigate the pulsed laser-induced damage performance and optoelectronic properties (at wavelength ~ 1 µm) of model nanophotonic thin films including gold, indium tin oxide, and alternative refractory materials such as titanium nitride and titanium oxynitride. We find that gold exhibits the best laser damage resistance compared to other plasmonic films of comparable thicknesses. We show that large absorption losses arising from high carrier concentrations and low mobilities in alternative plasmonic thin films, lead to exacerbated degradation and poorer laser damage performance. We will also present advanced strategies for engineering damage resistance and optical performance of nanophotonic thin films for high laser power applications.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-XXXXXX. LLNL-ABS-834545
Show Abstract +
In this initial study, Random AR (RAR) nano-structures were etched into monocrystalline chemical vapor deposited (CVD) diamond windows. Photothermal common-path interferometry (PCI) measurements at 1064nm were conducted in order to characterize the level of absorption at the surfaces and through the bulk of diamond substrates. Nano-second pulsed laser induced damage threshold (LiDT) measurements at 1064nm were conducted, and damage sites were analyzed via scanning electron microscopy (SEM) to understand damage mechanisms in both as-polished and RAR nano-textured diamond samples.
12300-17
On demand | Presented live 20 September 2022
Show Abstract +
We present a method for fabrication of spatially invariant substrate-engraved optical metasurfaces. The process is based on dry etching through a self-assembled nanoparticle etching mask generated via solid-state dewetting of a thin metal film on glass, giving rise to process scalability with mechanical durability and a high laser damage threshold. We will discuss the etch mask technology that enabled optimized metasurfaces for antireflective applications, and the performance of several large area metasurfaces designed for low reflectance and ultra-broadband / broad acceptance angle.
PC12300-18
CANCELED: Pulsed LiDT of electrochemically-formed RAR nano-structures on sapphire and YAG
20 September 2022 • 9:50 AM - 10:10 AM PDT
Show Abstract +
A dense texture of aluminum oxide surface relief structures was grown from a chemical solution on sapphire and YAG windows by anodic oxidation. Such randomly distributed, nanometer-scale features create a graded-index anti-reflection function with wideband performance and the potential for high laser damage resistance, benefits that are immediately scalable to large optics such as slab amplifiers and directed energy apertures. Micrographs of a matrix of prototypes with varying texture density and depth will be presented along with spectral transmission and reflection measurements, absorption scans, and the results of 1064nm nanosecond-pulse LiDT testing.
Poster Slams: Surfaces, Mirrors, and Contamination
20 September 2022 • 10:10 AM - 10:40 AM PDT
Session Chairs:
Christopher W. Carr, Lawrence Livermore National Lab. (United States), Carmen S. Menoni, Colorado State Univ. (United States)
Join the poster presenters of the Surfaces, Mirrors, and Contamination session for their two-minute oral slams. Each poster author is invited to give a brief (two-minute) preview of their research with a maximum of three slides during this poster slam session.
Poster authors: bring your slides on a USB drive to the session and be prepared to give a short summary of your poster.
The posters will be available for viewing at the Poster Session immediately following the poster slams.
View Poster Slam Schedule
View Poster Slam Schedule
Poster Session: Surfaces, Mirrors, and Contamination
20 September 2022 • 10:40 AM - 11:40 AM PDT | Meeting Room C
After the poster slam conference attendees are invited to attend the Surfaces, Mirrors, and Contamination poster session on Tuesday morning. Come view the posters, enjoy some coffee or tea, ask questions, and network with colleagues in your field.
Poster Setup: Tuesday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
Poster Setup: Tuesday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
PC12300-56
On demand | Presented live 20 September 2022
Show Abstract +
Recent advances of multi-PW lasers, such as the High Power Laser System from ELI-NP, made possible to achieve a peak power in excess of 10 PW.
The high-power femtosecond (fs) laser pulses require optics with Laser-Induced Damage Threshold (LIDT) qualified using ISO-compliant tests in the same pulse duration, spot size, and repetition rate range.
Experimental set-ups, in air and in vacuum, for qualification of the LIDT and the optical non-linearities were developed at ELI-NP. Their most important features are related to the complete automation, the laser pulse duration (25-100 fs), spot size (from 25 µm to 55 mm), gaussian/flat-top beams, test type (1:1, S:1, pass/fail), and the in-situ detection method, which are adapted along the ISO standards for the LIDT qualification process. A damage criterion based on the Fourier analysis of the spatial modulations of the reflected/transmitted laser pulses is proposed.
PC12300-57
On demand | Presented live 20 September 2022
Show Abstract +
Novel high power devices such as laser scanning modules require mirrors with special characteristics. The mirrors reflectivity at different angles and low stress are of high importance. Therefore, hybrid mirrors are often employed. We investigated the damage behavior of different hybrid mirror batches under cw-laser irradiation. Afterwards, we studied the resulting survival curves of the mirrors and compared the rise of the damage probability curve in dependence of the incident power with the samples optical characteristics. Eventually, a connection between the steepness of the damage probability curve and the variance of the optical characteristics within one mirror batch was observed.
PC12300-60
On demand | Presented live 20 September 2022
Show Abstract +
We evaluate the impact of several mitigation strategies on the damage
initiation rate and install life of the beam sampling optics (GDS) on the
National Ignition Facility (NIF). Both the initiation rate and the install
lifetime use units of Log Growth (LG) which is based on average growth of
large damage sites on the exit of surface of fused silica as a function of
cumulative power/energy of NIF laser shots.
In this work we show that the addition of the Fused Silica Debris Shield
(FSDS) improve the install lifetime of new GDS optics by 70%. Furthermore,
we show the install lifetimes of recycled GDS optics are more than doubled
by using additional mitigation strategies such as expanding mitigation
processing to include all damage sites Larger Than 10µm (LT10) rather than
just Larger Than 50µm (LT50). Despite this improvement, there is still a
difference between new and recycled optic install lifetimes. We show that
recycled optics have a higher apparent initiation rate than new optics.
12300-61
On demand | Presented live 20 September 2022
Show Abstract +
Laser-induced contamination (LIC) degrades the performance of optical components and can result in optical losses or even laser-induced damage. LIC deposit formation limits reliable operation of high repetition rate industrial lasers. In this work, we investigate LIC growth on dielectric oxide thin films in air environment irradiated by MHz sub-ps laser at 515 nm. We study the LIC growth dynamic in dependence on thin film deposition method, thin film material and thin film thickness.
PC12300-62
On demand | Presented live 20 September 2022
Show Abstract +
The poster will report the Laser Induced Damage Threshold of an amplifier medium immersed in an active cooling system, and with different protocols, as 1on1 and Son1 procedures to evaluate the influence of the cooling system on the laser damage resistance. Some theoretical investigations will also be reported in order to explain the different experimental observations.
PC12300-71
On demand | Presented live 20 September 2022
Show Abstract +
Rapidly growing irradiation fluences of continuous-wave (CW) laser systems require up-to-date optical components that are suitable to withstand demanding working conditions. To manufacture optics with required properties, Altechna has tested and chosen the perfect combination of substrate material, pre-treatment process and coating technology. It allowed us to develop low-absorption, increased-LIDT AR and HR coatings that are able to withstand high CW irradiation fluences in IR region without overheating and getting damaged. All of this was achieved by listening to our customers and searching for the best solutions.
Break
Lunch Break 11:40 AM - 1:10 PM
Session 5:
Mini-Symposium on Application of Metasurface Optics for use with High-Power Lasers II
20 September 2022 • 1:10 PM - 3:00 PM PDT
Session Chairs:
Nathan J. Ray, Lawrence Livermore National Lab. (United States), Laurent Lamaignère, CEA-Cesta (France)
PC12300-19
Flat optics with metasurfaces for imaging, sensing, and laser applications
(Keynote Presentation)
20 September 2022 • 1:10 PM - 1:40 PM PDT
PC12300-20
CANCELED: Damage resistance of randomly nano-structured multilayer high reflectors
20 September 2022 • 1:40 PM - 2:00 PM PDT
Show Abstract +
Randomly distributed, nanometer size surface-relief structures fabricated through several layers at the top of a multilayer dielectric mirror, have the potential to increase laser damage resistance. In this work, a simplified 1D model is detailed for the nominal design of such Random High Reflectors (RHRs). Prototype RHRs are fabricated, characterized, and then optimized in comparison with 3D finite element method simulations. To bolster the physical picture derived from these numerical models, measurements of surface absorption will be made and correlated with standardized ns-pulse LiDT testing at 1064nm wavelength.
PC12300-21
20 September 2022 • 2:00 PM - 2:20 PM PDT
Show Abstract +
All-silica mirrors manufactured using GLancing Angle Deposition (GLAD) are a promising approach for optics with improved LIDT. However, water content may increase over time due to the porosity of the low index silica layers, potentially changing the LIDT. Additionally, consecutive irradiation during LIDT testing may remove stored water and influence the LIDT.
Laser calorimetry, spectrophotometry and LIDT measurements, applying S-on-1 and R-on-1 methods, were used in order to determine the impact of laser-induced removal of stored water on the absorption, spectral behavior and laser damage resistance of all-silica mirrors. Influence of water reabsorption was investigated under different environmental atmospheric conditions.
12300-22
On demand | Presented live 20 September 2022
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The LiDT of RAR nano-textured optics has been shown to be many times higher than thin-film AR coated optics at UV through NIR wavelengths. Because the nano-texture is formed by a plasma process that removes part of the optic surface, the increase in damage resistance has also kept track with the LiDT advances attained by low roughness polishing and damage pre-cursor mitigation techniques. In this work the effect on the LiDT of plasma-polishing the surfaces of fused silica optics before and after nano-texturing was investigated. This mitigation process was characterized through surface roughness measurements, photothermal absorption measurements, and ns-pulse LiDT testing at 266nm.
PC12300-23
20 September 2022 • 2:40 PM - 3:00 PM PDT
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We present a method for producing durable thin optics for high-power lasers, using scalable process for spatially patterned glass engraved metasurface. The process is based on forming an etch-mask using laser raster-scan of a thin metal film on a glass, followed by dry-etching and removal of the metal mask. We present fabricated structures, and characterization of their optical performance, mechanical stability, and laser damage performance.
Poster Slams: Thin Films
20 September 2022 • 3:00 PM - 3:30 PM PDT
Session Chairs:
Christopher W. Carr, Lawrence Livermore National Lab. (United States), Carmen S. Menoni, Colorado State Univ. (United States)
Join the poster presenters of the Thin Films session for their two-minute oral slams. Each poster author is invited to give a brief (two-minute) preview of their research with a maximum of three slides during this poster slam session.
Poster authors: bring your slides on a USB drive to the session and be prepared to give a short summary of your poster.
The posters will be available for viewing at the Poster Session immediately following the poster slams.
View Poster Slam Schedule
View Poster Slam Schedule
Poster Session: Thin Films
20 September 2022 • 3:30 PM - 4:30 PM PDT | Meeting Room C
After the poster slam conference attendees are invited to attend the Thin Films poster session on Tuesday afternoon. Come view the posters, enjoy some coffee or tea, ask questions, and network with colleagues in your field.
Poster Setup: Tuesday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
Poster Setup: Tuesday 7:40 AM – 8:00 AM
View poster presentation guidelines and set-up instructions.
PC12300-63
On demand | Presented live 20 September 2022
Show Abstract +
Summary
We report on a method of coating striated composite (StriCom) layers via exposure to two different evaporant vapor plumes where local exposure to each plume is controlled via shielding that prevents simultaneous exposure. The properties of the resulting layers have been evaluated for laser-induced–damage thresholds (LIDT’s) at 1053 nm with 600-fs pulses and for thin-film stresses. The results indicate that hafnia/silica StriCom layers exhibit LIDT’s between those of the individual materials, depending on relative concentrations, but with improved damage performance where, for a refractive index of ≤ 1.65, the damage threshold is similar to that of silica.
Show Abstract +
The removal of multi-compound protective thin PVD films for stressed industrial tools using laser ablation could enhance or replace currently used procedures. Developing a laser removal process can shorten the process time and costs. In the first step, the laser induced damage threshold of the thin CrAlSiN coating and the WC-Co material was measured. Nanosecond and picosecond laser pulses were used for comparison. Furthermore, the dependence of the ablated material volume and ablation depth on the fluence and the number of pulses was measured. Finally, spectral analysis of the laser plasma generated during ablation was performed.
PC12300-65
On demand | Presented live 20 September 2022
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The Extreme Photonics Applications Centre (EPAC) is an upcoming state-of-the-art laser facility for research in academia and industry currently under construction at the Central Laser Facility in the United Kingdom. It will house a PW-level Ti:Sa laser system, operating at an unprecedented pulse rate of 10 Hz. To ensure success, we performed in-house damage testing of broadband (750-850 nm) anti-reflective coatings for EPAC Ti:Sa optics. We describe our test setup and present our results for coatings deposited by a range of suppliers and deposition techniques.
PC12300-66
On demand | Presented live 20 September 2022
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Our research focuses on the pre-ablation and ablation regimes of very thin metallic layers, by studying different samples of Au and Al films with thicknesses ranging from 5 to 100 nm, deposited on borosilicate glass substrates. On these samples, fluence-dependent single-shot measurements have been performed. We find that for pump fluences lower than values where crater formation (ablation) occurs, the probe reflectivity from the illuminated site, long after pump pulse excitation, is slightly higher than before the illumination. Our measurements provide insight into the fluence regime where light begins to affect materials before catastrophic damage occurs.
12300-67
On demand | Presented live 20 September 2022
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Optical elements are the main parts in laser system limiting the total generated output power due to optical resistivity. Improving the optical resistance of coatings is necessary for moving forward into this topic. All-silica mirrors were formed using glancing angle deposition method and conditioning effect was applied in order to increase resistance to laser radiation, reaching LIDT values up to 200 J/cm2 using 355 nm wavelength 2.05 ns pulsed laser.
12300-68
On demand | Presented live 20 September 2022
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The rapid deployment of high-energy laser systems has significantly pushed the practical limit of laser-induced optics damage. Most systems have chosen to scale the aperture of the laser system to operate within the damage limitations. However, most damage testing protocols do not take into consideration the sampling area of the damage testing beam with respect to the size of the extraction aperture. In this work, we review examples of laser systems where damage testing with small-scale S-on-1 results failed to predict the damage subsequently observed on a full aperture system. We provide guidance on how to adjust the post-coating damage testing protocol to gain confidence that the full-aperture optic will not be damaged during nominal high-fluence operations.
Session 6:
Fundamental Mechanisms
20 September 2022 • 4:30 PM - 5:50 PM PDT
Session Chairs:
Andrius Melninkaitis, Vilnius Univ. (Lithuania), Laurent Lamaignère, CEA-Cesta (France)
PC12300-24
20 September 2022 • 4:30 PM - 4:50 PM PDT
Show Abstract +
Anti-reflective (AR) coatings are frequently used for imaging and laser-related applications, however, their highest possible output power is limited by laser-induced damage threshold (LIDT). LIDT data for AR-coated nonlinear crystals is very limited, especially when it comes to pulse temporal scaling laws. Therefore, we investigated four identical lithium triobate (LBO) crystals deposited with the AR@1064+532 nm coating on one side and the AR@355 nm coating on the opposite side. Numerous tests were conducted following 1-on-1 and S-on-1 testing protocols at UV as well as IR wavelengths in the pulse duration range of 50 fs - 9 ns. To interpret experimental findings, we analyze empirical pulse temporal scaling laws of LIDT for distinct failure modes. Furthermore, we also considered numerical analysis based on rate equations.
PC12300-25
20 September 2022 • 4:50 PM - 5:10 PM PDT
Show Abstract +
Transverse stimulated raman scattering (TSRS) in potassium dihydrogen phosphate (KDP) and deuterated potassium dihydrogen phosphate (DKDP) plates for polarization control is a well-recognized limitation, giving rise to parasitic energy conversion and laser-induced damage. TSRS amplification is a coherent process that grows exponentially and distributed nonuniformly in the crystal and at the crystal surfaces. To understand the growth and spatial distribution of TSRS energy, a modeling approach was developed to simulate operational conditions in inertial confinement fusion-class laser systems. The result helps assess upper limits for operational conditions and guide possible ways to suppress the TSRS gain.
PC12300-26
20 September 2022 • 5:10 PM - 5:30 PM PDT
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We show that high repetition rate supercontinuum generation in solids is accompanied by the emission of conical third harmonic, whose occurrence serves as straightforward indication of the onset of in-bulk optical damage at its early stage. It is shown that conical third harmonic generation obeys noncollinear phase matching condition, which involves reciprocal lattice vector of a nanograting inscribed by femtosecond filament in the volume of transparent material. The universality of phenomenon is justified by the experiments in various transparent crystals and glasses and under various settings of focusing condition, pulse energy, repetition rate, exposure time and laser wavelength.
PC12300-27
20 September 2022 • 5:30 PM - 5:50 PM PDT
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Understanding the physical process behind laser-induced damage of multilayer dielectric (MLD) interference coatings (IC) is of supreme importance for building ultrahigh-intensity laser systems. We experimentally studied the S-on-1 laser-induced damage threshold (LIDT) and damage characteristics of the SiO2/HfO2 high reflector quarter-wave stacks for three different femtosecond pulse durations operating at 1030nm wavelength. The S-on-1 LIDT for 1,10,100,1000 and 10000 pulses were recorded, and the values compare well with the state of the art. A strong correlation between single-shot damage morphology and laser focal intensity profiles was observed. Potential damage mechanisms of IC layers consistent with our observation will be discussed.
Closing Remarks
20 September 2022 • 5:50 PM - 6:00 PM PDT
Christopher W. Carr, Lawrence Livermore National Lab. (United States)
Opening Remarks
21 September 2022 • 8:00 AM - 8:10 AM PDT
Detlev Ristau, Laser Zentrum Hannover e.V. (Germany)
Session 7:
Surfaces, Mirrors, and Contamination
21 September 2022 • 8:10 AM - 10:20 AM PDT
Session Chairs:
Jonathan W. Arenberg, Northrop Grumman Corp. (United States), Amy L. Rigatti, Univ. of Rochester (United States)
PC12300-28
Identifying, understanding, and suppressing of ns laser damage precursors in dielectric thin films
(Keynote Presentation)
21 September 2022 • 8:10 AM - 8:40 AM PDT
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We will present our recent advances in identifying, understanding, and suppressing ns laser damage precursors in IBS produced dielectric films under UV, pulsed laser exposure. Model systems of single layer, layer pairs, and MLD coatings of silica, hafnia, scandia, and alumina were investigated. Through materials characterization, laser damage testing and simulations, we revealed that entrapped nanobubbles were important low fluence laser damage precursors. We further demonstrated that the identified precursors could be suppressed by either post low pressure thermal annealing or the manipulation of deposition process including using different sputtering gases to achieve ns UV-laser damage resistant dielectric coatings.
12300-29
On demand | Presented live 21 September 2022
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Laser-induced contamination (LIC) can be a major concern of using UV laser systems. Surface contamination occurs via interactions between the UV laser and particulates, water vapor condensate, organics, and airborne molecular contaminates (AMC) from the environment or outgassing from system materials. A brief review of contamination of optics will lead into present results from long-term 355 nm quasi-CW laser transmission experiments at Edmund Optics. Time lapse microscopy was used to monitor nucleation and growth of surface contaminants. Laser burn boxes were constructed for use as a controlled UV LIC testbed; experimental results are presented on transmission losses for various material preparation methods.
12300-30
On demand | Presented live 21 September 2022
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We outline the development of a high-power deformable mirror device, based on a modified Thorlabs DMH40, employing a low-loss substrate-transferred crystalline coating as the reflective element. In standard components, this system features a metal coated (Ag or Al) 18 mm diameter × 150 µm thick BK10 glass substrate mounted to a 40-segment actuator, enabling Zernike compensation up to 4th order, with a peak-to-valley stroke up to ±17.6 µm. In the custom variant described here, the metal coating is replaced with a high-reflectivity (~99.998%) and low-stress (~130 MPa compressive) monocrystalline GaAs/AlGaAs Bragg stack transferred to the thin glass substrate via direct bonding. While maintaining similar physical performance, this custom system exhibits a substantial enhancement in power handling, with laser-induced damage tests (performed by Spica Technologies, Inc.) yielding a continuous-wave damage threshold of 75 MW/cm2 at 1070 nm (1/e2 spot diameter of 32.8 μm).
PC12300-31
21 September 2022 • 9:20 AM - 9:40 AM PDT
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In this work, we will review and evaluate the laser-induced optics damage observed on the final compressor gratings of the Advanced Radiographic Capability (ARC) laser. Damage initiation and growth rules are derived from online inspections and both measured and modeled laser performance are compared to a laser damage performance assessment of compressor grating witness samples performed offline. In addition, we will report the result of adapting these damage and growth rules to conditions relevant for the Scalable High-average-power Advanced Radiographic Capability (SHARC) 10 Hz Petawatt laser concept.
PC12300-32
21 September 2022 • 9:40 AM - 10:00 AM PDT
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Laser-damage performance of optics is known to be negatively affected by microscale particle contamination induced by the operational environment. In this work, we discuss our approach to quantifying particulates found inside the grating compressor chamber in the OMEGA EP Laser System. Particulate was collected at specific locations near multilayer dielectric (MLD) gratings and MLD high reflectors and subsequently characterized using optical microscopy, scanning electron microscopy, and energy dispersive x ray spectroscopy. Initial results suggest that higher concentrations are observed near the beamline ports from the target chambers.
12300-33
On demand | Presented live 21 September 2022
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A novel damage mitigation technique utilizing arrays of cones on the input surface to arrest the growth of exit surface damage by diffracting incoming light and casting a shadow on exit surface damage is discussed. Direct measurements have been made of the intensification caused by three and four cone array structures in the bulk, at the exit surface, and downstream. Measurement of the depth profile of the cone arrays have been utilized in both propagation and ray tracing models. We will report the efficacy of this mitigation method on arresting damage while eliminating dangerous downstream intensification.
Break
Coffee Break 10:20 AM - 10:50 AM
Session 8:
Thin Films I
21 September 2022 • 10:50 AM - 12:00 PM PDT
Session Chairs:
S. Roger Qiu, Lawrence Livermore National Lab. (United States), Lars O. Jensen, TRUMPF Laser Marking Systems AG (Germany)
PC12300-34
Path towards robust coatings for ELI Beamlines
(Keynote Presentation)
21 September 2022 • 10:50 AM - 11:20 AM PDT
PC12300-36
21 September 2022 • 11:20 AM - 11:40 AM PDT
Show Abstract +
The high-average-power petawatt-class Big Aperture Thulium (BAT) laser concept was proposed to meet the requirements for the next-generation compact particle accelerators. Our previous work reported the laser damage test and modeling of pulse compression gratings designed for the BAT laser and operating at 2 micron wavelength. Notably, we observed blister formation of the underlying layers at low fluences and ablation of the grating pillars at higher fluences. Here we present the measurement and analysis of these bulging damage precursors on the MLD gratings and mirrors using the cross-sectional transmission electron microscopy combined with focused ion beam processing.
PC12300-37
21 September 2022 • 11:40 AM - 12:00 PM PDT
Show Abstract +
More than 50 large aperture optics coated by Safran Reosc have been delivered to LULI for the APOLLON laser facility. Coating designs, processes and measurements are discussed with regard to the requirements. As a part of these optics is mounted on the beam line, we present operational performances with a specific focus on LIDT. This paper also relates the challenge to give a reliable LIDT value within a specific application toward the coatings of those component that have been tested by several LIDT-testing facilities. This test results are discussed and compared with LIDT test performed with the APOLLON laser beam.
Break
Lunch Break 12:00 PM - 1:30 PM
Session 9:
Thin Films II
21 September 2022 • 1:30 PM - 2:50 PM PDT
Session Chairs:
Daniel Kramer, ELI Beamlines (Czech Republic), David A. Alessi, Lawrence Livermore National Lab. (United States)
12300-38
On demand | Presented live 21 September 2022
Show Abstract +
We demonstrate a novel concept for an all-optical switch based on the optical Kerr-effect in thin film interference coatings. The switching between transmittance and reflectance relies on highly Kerr-active coating materials in combination with large internal intensity enhancement in thin film interference coatings. The paper investigates the switching performance as well as its relation to the laser induced damage threshold of these novel components. A modulation depth of 30 % was achieved without damage to the component, which very promising for later applications as power limiters or mode locking components.
12300-39
On demand | Presented live 21 September 2022
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Crystalline sesquioxide films (Sc2O3, Y2O3, and Lu2O3) produced by pulsed laser deposition were examined for laser damage resistance with pulses of 500 fs duration, at a wavelength of 1030 nm and at a 10 Hz repetition rate. Comparable tests were performed with amorphous magnetron-sputtered thin films (SiO2, HfO2, and Nb2O5). We found the laser-induced damage thresholds of the sesquioxides are close to those of HfO2 in the multi-pulse test regime. The results are the basis for designs of damage resistant reflective components used in ultrashort-pulse lasers.
12300-41
On demand | Presented live 21 September 2022
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A self-constructed ion beam sputtering machine capable to deposit large sized substrates up to a diameter of 550 mm is presented. Results are shown for IBS-coated beam transport mirrors of petawatt laser pulses that are enabled by latest advances in high intensity laser facilities. State of the art, such mirrors are mostly manufactured by thermal evaporation techniques. Their porous layer structure can cause unwanted specification changes when vacuum-air cycled. In contrast, the sputtered mirrors for the demanding ultra-short pulses of HAPLS (ELI beamlines) provide non-changing characteristics and showed no stress induced crazing as well as a very high LIDT.
12300-42
On demand | Presented live 21 September 2022
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The increase of continuous wave laser power is an important topic in various industrial and defense applications. One of the important limitation is due to the thin film component absorption. In order to study this absorption, it is of prime importance to measure and determine the origin of this absorption. We used Lock-In Thermography (LIT) to perform low-absorption measurement at 1,07 µm. A multipass setup was realized and calibrated with a sensitivity of a few ppm and a ten times better accuracy is demonstrated. Then this instrument was used to study single layers made with different materials and deposited by PIAD and commonly used multilayer components.
Conference Closing Remarks
21 September 2022 • 2:50 PM - 3:10 PM PDT
MJ Soileau, CREOL, The College of Optics and Photonics, Univ. of Central Florida (United States)
Conference Chair
CREOL, The College of Optics and Photonics, Univ. of Central Florida (United States)
Program Committee
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (China)