Infrared Laser System Research Articles

Corrosion property investigation of laser-cladding copper coating in the simulated nuclear waste disposal solution

To explore the efficient corrosion protection for the nuclear waste storage containers, pure copper coatings were successfully prepared on the 20# steel pipe surface using an infrared laser system under different laser powers. The study was conducted on the copper coatings, encompassing the surface quality, defects, microstructure, elemental distribution, phase composition, and corrosion products. The electrochemical and immersion corrosion behavior of the copper coatings in simulated nuclear waste disposal solutions was analyzed. The pure copper coating prepared by 2800 W laser power has fewer amounts and smaller sizes of defects inside the coating with only a slight fusion of Cu and Fe elements at the interface, which exhibits the highest corrosion potential and the smallest self-corrosion current density. During the immersion corrosion process, pores and unfused defects inside the coating, as well as the pits formed by galvanic coupling corrosion, lead to enhanced acidity inside these defects, resulting in a higher corrosion rate. As the immersion time proceeds, the corrosion rate slows down gradually and the content of Cu2+ corrosion product increases significantly.

Preliminary Investigation of Thermoelectric Electromotive Force Oscillation of NiCr/NiSi Thin Film Thermocouple in Dynamic Calibration.

In order to reveal the dynamic response characteristic of thin film thermocouples (TFTCs), the nichrome/nisil (NiCr/NiSi) TFTCs are prepared onto the glass substrate. With short pulse infrared laser system, NiCr/NiSi TFTCs are dynamically calibrated. The thermoelectric electromotive force (TEF) curves of NiCr/NiSi TFTCs are recorded by the memory hicorder system, which could reflect TEF signals with resolution ratio in nanosecond and microvolt, simultaneously. With increasing laser energy from 15.49 to 29.59 mJ, TEF curves display more and more violent oscillation, even negative value. The results show that the bounce of thermal energy happens between two interfaces of TFTCs because the thermal conductivity of glass and air is significantly lower than that of NiSi/NiCr TFTCs. The bounce of thermal energy results in the obvious decrease of nNiCr and nNiSi, as well as oscillation of TEF. For laser energy in 29.59 mJ, the bounce of thermal energy in NiCr film could result in nNiCr < nNiSi. Then, TEF value appears abnormal negative value. Based on the results, the complex thermal energy transport process in TFTCs dynamic calibration is revealed, which results in the oscillation of thermal energy and TEF signal.

Optically pumped polarized [formula omitted]He[formula omitted] ion source development for RHIC/EIC

The proposed polarized 3He++ acceleration in RHIC and the future Electron-Ion Collider will require about 2×1011 ions in the source pulse. A new technique had been proposed for production of high intensity polarized 3He++ ion beams. It is based on ionization and accumulation of the 3He gas (polarized by metastability-exchange optical pumping and in the 5T high magnetic field) in the existing Electron Beam Ion Source (EBIS). A novel 3He cryogenic purification and storage technique was developed to provide the required gas purity. An original gas refill and polarized 3He gas injection to the EBIS long drift tubes, (which serves as the storage cell) were developed to ensure polarization preservation. An infrared laser system for optical pumping and polarization measurements in the high 3–5T field has been developed. The 3He polarization 80–85% (and sufficiently long ∼30min relaxation time) was obtained in the “open” cell configuration with refilling valve tube inlet and isolation valve closed. The development of the spin-rotator and 3He4He absolute nuclear polarimeter at 6MeV 3He++ beam energy is also presented.

Laser absorption study of the N2+ O → NO + N and NO + O → O2+ N Zeldovich reactions in shock-heated N2O mixtures

The fast decomposition of nitrous oxide (N2O) into molecular nitrogen (N2) and atomic oxygen (O) was leveraged to probe the N2 + O and NO + O Zeldovich reactions behind reflected shocks in experiments spanning 2000–6800 K and 0.04–1.67 atm in 1% and 5% N2O diluted in either argon (Ar) or N2, respectively. One infrared (IR) and two ultraviolet (UV) laser absorption diagnostic systems probed N2O and NO. The IR laser system probed N2O in isolation, while the two UV laser systems probed a combination of N2O, NO, and O2 using an online/offline method. The resulting absorbance time-histories were used to infer the NO rotational temperature and the number densities of N2O and NO. The number density time-histories were used to infer (1) the N2O dissociation rate to form N2 and O ( k d N 2 O − [ M ]), (2) the reaction rate of N2O and O to form two NO ( k d N 2 O − O , 1), (3) the NO + O Zeldovich reaction rate ( k z NO − O), and (4) the N2 + O Zeldovich reaction rate ( k z N 2 − O). The experiments were insensitive to the reaction rate of N2O and O to form O2 and N2 ( k d N 2 O − O , 2) at high temperatures. Generally, k d N 2 O − [ M ] was inferred from IR and UV offline data, with k d N 2 O − O , 1, k z NO − O, and k z N 2 − O inferred from UV online data in Ar and N2 dilution. Each inferred reaction rate shows consistency with literature, while extending data to higher temperatures with reduced uncertainty. The reduced uncertainty is sufficient to enable comparisons of the data to various high-temperature quantum chemistry models.

Numerical modeling and experimental validation of meat burgers and vegetarian patties cooking process with an innovative IR laser system

AbstractIn this paper, a numerical model for the simulation of the cooking process of meat burgers and vegetarian patties by means of an IR laser beam is presented. The innovative cooking system is thought to be integrated within a 3‐D printer prototype where the food sample is placed on a rotating plate. The numerical model consists of two different tools. First, a simplified 0‐D model, aimed at studying the heat transfer processes between the food sample, the lower plate, and the surrounding environment. Second, a 3‐D finite‐volume algorithm, which is employed to simulate the temporal and spatial evolution of the temperature within the food sample, when subjected to a laser beam which follows a given path. In parallel, an experimental test campaign is carried out to measure the temperature and cooking losses evolution inside burgers and patties. The results of the experimental campaign on the evolution of the temperature inside meat burgers and vegetarian patties are used to validate the numerical method, showing a good agreement. Next, the numerical method is used to carry out a parametric analysis of the IR laser system, aimed at analyzing and optimizing cooking parameters as laser power, incidence time and reversal time.Practical ApplicationThe current practical application of the numerical model presented here consists on the development of 3D food printers' prototypes which incorporate an infrared laser cooking system. IR laser cooking is a new cooking method currently under research which requires an adequate experimental design and an intense experimental work. The numerical models presented here allows an effective estimation of spatial and temporal distribution of real cooking temperatures during an infrared (IR) laser cooking process, allowing the analysis of pasteurization temperatures needed to inactivate pathogenic bacteria. The numerical simulation tool can be used to optimize and develop the IR laser system by analyzing different parametric conditions, as the ray tracing function frequency (incidence time), the reversal time of the burger, and the laser power. Simulations are aimed at simplifying and guiding the experimental work, leading to time and material savings, and it would also help to determine the most significant variables involved in the cooking process. The present model can be integrated as a new application of the laser control software and can be used in a professional gastronomic environment to choose between different cooking degrees, to analyze the characteristics of the printed food, or to determine the appropriate cooking parameters required to ensure food safety. The ability to 3D print and cook in the same physical area may facilitate a better implementation of the 3DFP technology in different markets.

Optical Coherence Tomography Feedback System for Infrared Laser Sealing of Blood Vessels.

Infrared (IR) lasers have recently been tested as an alternative to electrosurgical and ultrasonic laparoscopic devices for optical sealing of blood vessels. IR laser technology previously demonstrated faster sealing times, reduced thermal spread, and lower device temperatures during experimental studies. However, current commercial laparoscopic devices incorporate electrical impedance and/or temperature sensors as real-time, closed-loop, feedback to indicate successful blood vessel seals. This preliminary study explores an infrared laser system for sealing and optical coherence tomography (OCT) as a potential feedback system for successful vessel seal verification. A 1470-nm diode laser delivered an incident power of 30 W for an irradiation time of 5 s using an 8 × 2 mm linear beam, for creating strong seals in porcine renal blood vessels under compression. After sealing the blood vessels, OCT was performed on unsealed and sealed vessel regions for comparison. Standard vessel burst pressure (BP) measurements confirmed successful seals after OCT. Integrated reflectance intensity in OCT A-scans decreased by an average of 20 ± 6% in sealed versus native vessels of 2.4 ± 0.4 mm diameter. Vessel BP measured 532 ± 239 mmHg, with all vessels (n = 25) recording a successful BP > 180 mmHg (hypertensive blood pressure). Unsealed vessels demonstrated significantly deeper imaging marked by a continuous decay in reflected intensity, while sealed vessels showed subsurface reflectance intensity peaks, immediately followed by a rapid decay in reflectance intensity. These markers are consistent with increased light scattering and decreased optical penetration depth upon thermal coagulation of tissues. A-line OCT data consistently differentiated between sealed and unsealed blood vessel regions. Future work will involve OCT integration into the laparoscopic device for real-time optical feedback during IR laser sealing.

Laser dewetting mechanism and antibacterial properties of Cu-Al based medium entropy alloy films

High entropy alloys (HEAs) have attracted significant interest in recent decades due to their unique microstructures and many favorable properties, including high mechanical strength, good thermal stability and excellent corrosion resistance. In the present study, three Cu-Al based medium entropy alloys (MEAs), namely CuAlAg (CAA), CuAlZn (CAZ) and CuAlV (CAV), are deposited on glass substrates using a high-vacuum sputtering system. The as-sputtered MEA films (MEAFs) are processed by Rapid Thermal Annealing (RTA) for 5 min in order to stabilize their microstructures and are then dewetted using a near infrared (NIR) fiber laser system with various repetition rates, pulse powers and scan speeds to produce nanoparticle structures. Finally, the antibacterial properties of the MEAFs and dewetted films are investigated using three bacterial strains, namely Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. It is shown that the particle size of the dewetted films decreases as the accumulated energy (AE) density increases. The smaller particle size leads to a blue shift of the localized surface plasmon resonance (LSPR) absorption peak wavelength as a result of the greater uniformity of the induced electromagnetic field. In the dewetting process, the Ag and Cu elements of the MEAFs form particles, while the Al atoms are repelled to the bottom or surrounding region of the nanoparticles, and the Zn and V atoms remain on the glass surface. The MEAFs and dewetted films show an antibacterial efficiency of 100% for all three bacterial strains after 24 h. Moreover, the bacterial growth curves indicate that the majority of the bacteria are destroyed within 4–5 h of contact. The antibacterial effect of the MEAFs and dewetted films is attributed to the production of reactive oxygen species (ROS) and the release of metal ions, which collectively destroy the cell membranes and lead to cell shrinkage and death. For all of the MEAFs, the antibacterial performance improves after dewetting as a result of the increased surface contact area provided by the nanoparticles. Overall, the present results confirm the effectiveness of MEAs and dewetted films in realizing thin-film coatings with enhanced antibacterial properties.

Laser‐Assisted Printing of Electrodes Using Metal–Organic Frameworks for Micro‐Supercapacitors

AbstractDirect laser scribing, an advanced printing technique, has been recently developed to enable the carbonization of carbonaceous precursors in a rapid, precise, and cost‐effective manner. Herein, it is reported that metal−organic frameworks (MOFs) can be converted into patterned derived carbon with desired structural features using a CO2 infrared laser system. Metal species in MOFs play a key role in the morphology, porous structure, and crystallinity of the resulting laser‐induced products by studying six representative MOFs. Diverse features such as ordered porous structure and continuous network microstructure can be obtained in the laser‐induced MOF‐derived carbon, which is influenced by the melting and boiling points of metals and their magnetic and catalytic behaviors. Furthermore, a core–shell structured composite (MOF‐199@ZIF‐67) has been designed and prepared for the fabrication of 12‐interdigital electrodes derived from the composite by laser‐assisted printing. The as‐obtained electrodes with highly porous and hierarchical structure show an enhanced specific capacitance for micro‐supercapacitors (MSCs). This work provides a complementary heat treatment method to produce MOF‐derived carbon nanomaterials with desired structural features and patterns for MSCs and micro‐device‐related applications.

Modeling of a picosecond CO2 amplifier with electrical and optical pumping.

As a long-wavelength laser with strong energy storage capacity and large scale of amplification, the CO2 laser is considered an effective amplifier in the next-generation picosecond terawatt infrared laser system, but the pulse splitting effect caused by its discrete gain spectrum limits its behavior. In this paper, we have developed a specific model of a CO2 amplifier, which is optically and electrically pumped at the same time. The model is based on gas discharge that is combined with photon absorption, temperature, and wave equation. The proposed hybrid pumped CO2 amplifier scheme can increase the gain proportion of the sequence band transition (0002-1001, 0003-1002, etc.) from 12% to nearly 50% of the regular band and broaden the bandwidth of each line by over 15.8% by the overlap of the sequence band and regular band. The relative energy concentration of the first subpulse can be increased by up to 190% when the amplification factor reaches 103. The study on the model of a picosecond CO2 amplifier with electrical and optical pumping may contribute to the amplification of an ultrafast mid-infrared pulse to the terawatt or higher region.

Study on long-wave infrared ZnGeP2 subsequent optical parametric amplifiers with different types of phase matching of ZnGeP2 crystals

Pumped by a 100 W Q-switched Ho:YAG laser at 2090.7 nm with pulse repetition frequency of 10 kHz, four types of high-power long-wave infrared ZnGeP2 (ZGP) subsequent optical parametric amplifier (OPA) based on optical parametric oscillator (OPO) with different types of phase matching (PM) of ZGP crystals were demonstrated. For the results of 8.2 µm output characteristics at the full incident pump power, Type-II PM ZGP OPO with Type-II PM ZGP OPA had the best M2 of 1.8 and lowest average output power of 9.2 W with the narrowest linewidth of 77 nm, while Type-I PM ZGP OPO with Type-I PM ZGP OPA had the worst M2 of 2.2 and the widest linewidth of 122 nm, and Type-II PM ZGP OPO with Type-I PM ZGP OPA had the highest average output power of 12.6 W, corresponding to overall optical conversion efficiency of 12.6% from Ho to long-wave infrared laser system.

Fabrication and Properties of Josephson Junction Cantilevers for Terahertz Applications

Josephson cantilevers are employed to measure the three-dimensional radiation distribution at microwave frequencies and up to the terahertz regime. Epitaxial YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> Josephson junctions with high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> products are required at these frequencies. The commonly used epitaxial Josephson junctions on LaAlO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> bicrystal substrates fulfill these requirements but exhibit significant variance in their electronic properties. In addition, the substrate losses have to be minimized and, therefore, only substrate materials with low relative permittivity ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> and loss tangent tan δ in the microwave regime are suitable. The fabrication is realized by optimized pulsed laser deposition of YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> . The separated devices are automatically characterized including the electric I-V curves and temperature dependence. In addition, the microwave properties are determined in our terahertz microscope at 762 GHz with a far infrared laser system and low-noise measurement electronics. The Josephson cantilevers are used to measure the spatial power distribution of the laser beam by differential resistance analysis and by Hilbert transform of the first Shapiro step. The latter approach shows a good agreement with the expected beam profile.

Fiber optic coupled quantum cascade infrared laser system for detection of explosive materials on surfaces

The design and assembly of a unique infrared (IR) optical-fiber combined quantum cascade laser (QCL) system is described. This system integrates the output from four individual QCL modules, using infrared optical fibers, into a single output aperture to provide continuous spectral scanning from 6.02 to 11.17 µm. Spectra were collected on a diffuse gold reference as well as multiple concentrations of the explosive 1,3,5-Trinitro-1,3,5-triazinane (RDX) which were inkjet printed on aluminum substrates. The collected RDX spectra were compared to RDX spectra collected using a conventional Fourier-transform infrared spectrometer (FTIR). The results show good agreement between the spectra collected using the fiber-combined QCL system and the standard FTIR.These results demonstrate that the use of infrared optical fibers to combine multiple QCL modules is a viable approach to developing IR laser sources for use in fieldable devices capable of standoff detection of explosives.

Enhancing the Er3+: Infrared and mid-infrared emission performance in germanosilicate-zinc glasses

Rare earth doped luminescence glasses have been noteworthy recently in the fields of near-middle-infrared applications. In this work, serious Er3+ doped new kind of germanosilicate-zinc glasses have been investigated aiming to obtain efficient infrared and mid-infrared luminescence performance. The drastically reduced OH− content in present host support the enhanced 2.7 and 1.5 μm emissions corresponding to the 4I11/2 → 4I13/2 and 4I13/2 → 4I15/2 transitions owing to the decreased energy loss between OH− and active ions. Meanwhile, the energy transfer mechanism has been discussed based on both the infrared and visible spectra together with the measured decay curves. Hence, the large absorption and emission cross-sections indicate that this kind of germanosilicate-zinc glasses may provide high gain as a good medium for efficient infrared laser system.

Research on the Surface Evolution of Single Crystal Silicon Mirror Contaminated by Metallic Elements during Elastic Jet Polishing Techniques.

Metallic elements can contaminate single crystal silicon mirror during ion beam etching (IBE) and other postprocessing methods, which can affect the performance of components in an infrared laser system. In this work, scanning electron microscope (SEM) and atomic force microscope (AFM) were used to characterize the distribution of contaminant represented by aluminum (Al). After characterizing contaminated area, elastic jet polishing (EJP), EJP, and static alkaline etching (SAE) combined technique were used to process the mirror. The morphology and laser-induced absorption were measured. Results show that metallic elements can mix with silicon and generate bulges due to the sputtering effect. In addition, SAE and EJP combined technique can remove metallic contaminant and stabilize the surface quality. Research results can be a reference on conducting postprocessing technologies to improve laser damage resistance property of single crystal silicon mirror in infrared laser system.

How to get deeper structures with the same energy: Fabrication of periodic structures in stainless steel using Direct Laser Interference Patterning with burst mode ps-pulses

In this study, stainless steel substrates were treated with laser interference patterns using burst of pulses. The main objective is to evaluate their influence in the ablation mechanism using the Direct Laser Interference Patterning method. Using a 10 ps infrared laser system operating with low and high fluence levels and different pulse overlaps, a lower efficiency in the ablation process was observed for the low energy case, while at high fluences an improvement of the ablation efficiency up to 31% was observed. In addition, it was found that overlaps higher than 97.6% significantly deteriorate the pattern quality.

High repetition rate 102 W middle infrared ZnGeP2 master oscillator power amplifier system with thermal lens compensation.

We demonstrate a 102W middle infrared ZnGeP2 (ZGP) optical parametric amplifier (OPA) pumped by a 2097-nm Q-switched Ho:YAG laser at a pulse repetition frequency of 10kHz. The seed middle infrared laser was produced by a ZGP optical parametric oscillator. Its average power was 28.4W pumped by a 50W 2097-nm laser. By thermal lens compensation, the beam factor M2 reduced from 3.1 to 2.1. When the incident Ho pump power was 120W, the middle infrared ZGP OPA yielded the maximum average output power of 102W and slope efficiency of 61.7%. The overall optical conversion efficiency of 60% from Ho to middle infrared was obtained for the whole middle infrared laser system. In addition, at the maximum average output power, the beam quality factors of the middle infrared ZGP OPA were measured to be about 2.7 and 2.8 for horizontal and vertical directions, respectively.

Angle Dependent 3-D Directional Patterning of Flexible Films by Infrared Laser.

Laser direct patterning (LDP) technology has attracted great attention due to its process simplification and environmental friendliness. It is replacing the existing photo-lithography technology. Infrared (IR) laser equipment also has advantages such as low cost and long duration, although it is difficult to implement fine line width compared to ultraviolet (UV) or excimer laser. Therefore, it is very important to realize 3-D patterning system based on cheap infrared laser system. In this paper, 3-D infrared laser direct patterning system was designed by introducing an etching process on Ag paste/ITO/PET flexible film. Such 3-D patterned Ag paste/ITO/PET flexible films showed feasibility and effectiveness of 3-D laser directional patterning technologies. Etch ratio of the fabricated Ag paste/ITO/PET flexible film after 3-D infrared laser direct patterning was then systematically investigated.

Towards a petawatt-class few-cycle infrared laser system via dual-chirped optical parametric amplification

Expansion of the wavelength range for an ultrafast laser is an important ingredient for extending its range of applications. Conventionally, optical parametric amplification (OPA) has been employed to expand the laser wavelength to the infrared (IR) region. However, the achievable pulse energy and peak power have been limited to the mJ and the GW level, respectively. A major difficulty in the further energy scaling of OPA results from a lack of suitable large nonlinear crystals. Here, we circumvent this difficulty by employing a dual-chirped optical parametric amplification (DC-OPA) scheme. We successfully generate a multi-TW IR femtosecond laser pulse with an energy of 100 mJ order, which is higher than that reported in previous works. We also obtain excellent energy scaling ability, ultrashort pulses, flexiable wavelength tunability, and high-energy stability, which prove that DC-OPA is a superior method for the energy scaling of IR pulses to the 10 J/PW level.

Characterization of a novel miniaturized burst-mode infrared laser system for IR-MALDESI mass spectrometry imaging.

Laser systems are widely used in mass spectrometry as sample probes and ionization sources. Mid-infrared lasers are particularly suitable for analysis of high water content samples such as animal and plant tissues, using water as a resonantly excited sacrificial matrix. Commercially available mid-IR lasers have historically been bulky and expensive due to cooling requirements. This work presents a novel air-cooled miniature mid-IR laser with adjustable burst-mode output and details an evaluation of its performance for mass spectrometry imaging. The miniature laser was found capable of generating sufficient energy for complete ablation of animal tissue in the context of an IR-MALDESI experiment with exogenously added ice matrix, yielding several hundred confident metabolite identifications. Graphical abstract The use of a novel miniature 2.94μm burst-mode laser in IR-MALDESI allows for rapid and sensitive mass spectrometry imaging of a whole mouse.

Recent progress of phase-contrast imaging at Tsinghua Thomson-scattering X-ray source

Due to its small spot size, a Thomson-scattering X-ray source can produce high spatial coherent X-ray pulse, which is the prerequisite for phase-contrast imaging. In this paper, we will introduce the recent progress of phase-contrast imaging at Tsinghua Thomson-scattering X-ray source (TTX). Since the generation of first hard X-ray pulse at TTX in 2012, we have demonstrated the capacity of in-line phase contrast imaging using a refill of gel ink pen. And then, a Monte Carlo simulation tool for in-line phase-contrast imaging based on Thomson-scattering X-ray source has been developed. Taking advantage of this code, we calculate the typical requirement of photon numbers for in-line phase-contrast imaging based on this type of X-ray source. After the upgrade of infrared laser system and control program, the total photon yield of TTX has been increased to ∼2×107photons/pulse at X-ray central energy of 25keV and 50keV with RMS jitter less than 6% and 4% respectively. A new run of experiments about in-line phase-contrast imaging and phase-contrast computed tomography (CT) have been carried out at TTX.