Development Of Laser Technology Research Articles

Broadband nonlinear conversion and random quasi-phase-matching in transparent glass composite

With the development of laser technology, nonlinear optics plays a crucial role in frequency conversion. However, the generation of second harmonics in nonlinear optical crystals is generally subject to rigorous phase-matching conditions that hinder the performance of broadband tunability. It is believed that introducing disorders in nonlinear optical materials is helpful to overcome this obstacle. In this work, we have prepared a nonlinear microcrystal-doped glass (NMG) composite material, allowing for tunable and polarization-independent nonlinear conversion from visible to near-infrared. The linear dependence of SHG intensity versus sample thickness indicated the facilitation of random quasi-phase matching by using the NMG. Our results provide a more stable and promising platform for disordered nonlinear photonic materials and suggest the possibility of more efficient nonlinear conversions using the NMG composite glass fibers in future.

Applications of Microstructured Optical Fibers in Ultrafast Optics: A Review

With the development of laser technology, microstructured optical fibers (MOFs) have become an important part of ultrafast optics, providing excellent platforms for ultrafast laser pulse generation, amplification, and compression, promoting the development of fiber laser systems to generate high power, high pulse energy, and few-cycle duration pulses. MOFs extend the ultrafast laser spectrum to the vacuum ultraviolet (VUV) and even extreme ultraviolet (EUV) regions based on dispersive wave emission and high harmonic generation, as well as to the mid-infrared region based on soliton self-frequency shift (SSFS), contributing compact and low-cost light sources for precision microscopy and spectroscopy. In this paper, first several common types of MOFs are introduced, then the various applications of MOFs in ultrafast optics are discussed, mainly focusing on the aspects of ultrafast laser pulse scaling in pulse energy and spectral bandwidth, and finally the possible prospects of MOFs are given.

Interventional and device treatment of the periocular area

Growth in the research, innovation, and development of laser and energy-based technologies over the past few decades has led to dramatic increases in treatment options for dermatologic and cosmetic concerns of the periorbital area. We highlight recent treatment options using laser and energy-based devices for the clearance of periocular pigmented lesions, including solar lentigines and nevus of Ota; vascular lesions, including port-wine birthmarks, infantile hemangiomas, superficial telangiectasias, and reticular veins; laser ablation of benign tumors, such as xanthelasma; cosmetic rejuvenation; treatment of infraorbital dark circles and festoons; laser removal of eyebrow and eyeliner tattoos; and device-based treatment of chronic dry eyes.

Elucidating fungal decomposition of organic matter at sub-micrometer spatial scales using optical photothermal infrared (O-PTIR) microspectroscopy.

In microbiological studies, a common goal is to link environmental factors to microbial activities. Both environmental factors and microbial activities are typically derived from bulk samples. It is becoming increasingly clear that such bulk environmental parameters poorly represent the microscale environments microorganisms experience. Using infrared (IR) microspectroscopy, the spatial distribution of chemical compound classes can be visualized, making it a useful tool for studying the interactions between microbial cells and their microenvironments. The spatial resolution of conventional IR microspectroscopy has been limited by the diffraction limit of IR light. The recent development of optical photothermal infrared (O-PTIR) microspectroscopy has pushed the spatial resolution of IR microspectroscopy beyond this diffraction limit, allowing the distribution of chemical compound classes to be visualized at sub-micrometer spatial scales. To examine the potential and limitations of O-PTIR microspectroscopy to probe the interactions between fungal cells and their immediate environments, we imaged the decomposition of cellulose films by cells of the ectomycorrhizal fungus Paxillus involutus and compared O-PTIR results using conventional IR microspectroscopy. Whereas the data collected with conventional IR microspectroscopy indicated that P. involutus has only a very limited ability to decompose cellulose films, O-PTIR data suggested that the ability of P. involutus to decompose cellulose was substantial. Moreover, the O-PTIR method enabled the identification of a zone located outside the fungal hyphae where the cellulose was decomposed by oxidation. We conclude that O-PTIR can provide valuable new insights into the abilities and mechanisms by which microorganisms interact with their surrounding environments.IMPORTANCEInfrared (IR) microspectroscopy allows the spatial distribution of chemical compound classes to be visualized. The use of conventional IR microspectroscopy in microbiological studies has been restricted by limited spatial resolution. Recent developments in laser technology have enabled a new class of IR microspectroscopy instruments to be developed, pushing the spatial resolution beyond the diffraction limit of IR light to approximately 500 nm. This improved spatial resolution now allows microscopic observations of changes in chemical compounds to be made, making IR microspectroscopy a useful tool to investigate microscale changes in chemistry that are caused by microbial activity. We show these new possibilities using optical photothermal infrared microspectroscopy to visualize the changes in cellulose substrates caused by oxidation by the ectomycorrhizal fungus Paxillus involutus at the interface between individual fungal hyphae and cellulose substrates.

Principal Analysis and Application of Laser Technology in Integrated Circuits

Since the constant development of science and technology and the popularization of electronic devices, integrated circuits are also developing in the direction of large scale and high precision. This requires the processing of integrated circuits to be constantly refined. This also prompted the laser technology has become an important processing technology in the manufacturing process of large-scale integrated circuits. Laser processing technology is a non-contact processing, its beam diameter is small, high-energy density, high productivity, stable and reliable processing quality. This paper for the laser welding, laser direct writing, laser detection and laser cleaning overview of the four-laser technology in the application of large-scale integrated circuits. And the working principle, type and process characteristics of these laser technologies are discussed. The development of laser technology has also limited the production of large-scale integrated circuits in some aspects. With the semiconductor laser, excimer laser process continues to mature, laser technology in integrated circuits will continue to expand the scope of application and break through the obstacles.

The Versatile Applications of Distributed Bragg Reflector (DBR) Lasers: Sensing, Communication, And Beyond

Distributed Bragg Reflector (DBR) lasers have emerged as versatile and indispensable tools across various domains. Their advantages, including high signal-to-noise ratios, narrow linewidths, and support for distributed sensing, enable them to excel in diverse applications. DBR lasers have revolutionized optical fiber communication, medical diagnostics, and chaos-based key distribution. They provide precise control over wavelengths, making them valuable in fields such as dermatology, ophthalmology, and photodynamic therapy. Additionally, they play a critical role in flow cytometry, spectroscopy, and dental procedures. In the realm of sensing, DBR lasers have proven their efficacy in detecting parameters like temperature, pressure, current, magnetic fields, and ultrasound. Innovative techniques, such as FPGA-based demodulation and slotted DBR optical fiber lasers, have further enhanced their capabilities. As technology advances, the potential of DBR lasers in sensing and detection applications continues to grow. Their ability to deliver real-time, accurate data across various parameters positions them as essential tools for addressing complex scientific, medical, and industrial challenges. The future promises exciting developments in DBR laser technology, further expanding their role in solving multifaceted problems.

Generation of ultra-intense vortex laser from a binary phase square spiral zone plate.

With the development of ultra-intense laser technology, the manipulation of relativistic laser pulses has become progressively challenging due to the limitations of damage thresholds for traditional optical devices. In recent years, the generation and manipulation of ultra-intense vortex laser pulses by plasma has attracted a great deal of attention. Here, we propose a new scheme to produce a relativistic vortex laser. This is achieved by using a relativistic Gaussian drive laser to irradiate a plasma binary phase square spiral zone plate (BPSSZP). Based on three-dimensional particle-in-cell (3D-PIC) simulations, we find that the drive laser has a phase difference of π after passing through the BPSSZP, ultimately generating the vortex laser with unique square symmetry. Quantitatively, by employing a drive laser pulse with intensity of 1.3 × 1018~W/cm2, a vortex laser with intensity up to 1.8 × 1019~W/cm2, and energy conversion efficiency of 18.61% can be obtained. The vortex lasers generated using the BPSSZP follow the modulo-4 transmutation rule when varying the topological charge of BPSSZP. Furthermore, the plasma-based BPSSZP has exhibited robustness and the ability to withstand multiple ultra-intense laser pulses. As the vortex laser generated via the BPSSZP has high intensity and large energy conversion efficiency, our scheme may hold potential applications in the community of laser-plasma, such as particles acceleration, intense high-order vortex harmonic generation, and vortex X/γ-ray sources.

Nonadiabatic Dynamics near Metal Surfaces with Periodic Drivings: A Generalized Surface Hopping in Floquet Representation.

With light-matter interaction extending into the strong regime, as well as rapid development of laser technology, systems subjecting to a time-periodic perturbation have attracted broad attention. Floquet theorem and Floquet time-independent Hamiltonian are powerful theoretical frameworks to investigate the systems subjected to time-periodic drivings. In this study, we extend the previous generalized surface hopping (SH) algorithm near a metal surface (J. Chem. Theory Comput. 2017, 13, 6, 2430-2439) to the Floquet space, and hence, we develop a generalized Floquet representation-based SH (FR-SH) algorithm. Here, we consider an open quantum system with fast drivings. We expect that the present algorithm will be useful for understanding the chemical processes of molecules under time-periodic driving near the metal surface.

New type of coatings combining invisibility and high power laser protection function

With the rapid development of laser technology, the protection of high-energy lasers has received increasingly widespread attention. The current laser protection methods only have single function, and do not consider the detection technology. Based on this, this article proposes a bilayer coating system that combines invisibility and high energy laser protection performance. For surface layer, four types of carbon materials were used as fillers and two types of resins were used as base materials. For the bottom layer, both YSZ block and YSZ plasma sprayed coating were used. The results show that the carbon material in surface layer react with oxygen rapidly under laser irradiation conditions, achieving the rapid transition from invisible state to laser protection state. This bilayer coating has simple process and low cost, leading to great application value. Meanwhile, this method also provides inspiration for the design and preparation of other multifunctional coatings.

Ultrafast dynamics of water under photoexcitation

Experimental techniques and theoretical calculations have made significant breakthroughs recently in realizing the ultrafast time resolution and the understanding of microscopic details on the atomic scale, which have brought new insights into the ultrafast microscopic dynamics of water and aqueous systems. Here we focus on the dynamic processes of ionization, dissociation, as well as plasmonization of water molecules, water clusters, and liquid water under different intensities of light excitation.<br>The pump-probe technique allows one to extract information about the orbital-dependent phase shift during photoionization, corresponding to delays on time scales of tens to hundreds of attoseconds. Delay time in photoionization is found to be proportional to the delocalization of molecular/cluster orbitals. In addition, information related to the Feshbach resonance is also of interest. By solving the scattering equations, detailed information on the scattering cross section, the β-parameter, and the involved Rydberg orbitals during valence electron ionization of water is obtained.<br>For liquid water undergoing irradiation by an optical field, the tunnelling electrons are unable to move away and recombine with the parent molecule on a time scale of 100 fs if the external field is not strong enough (e.g., ~100 kV/cm). For terahertz fields as high as 250 kV/cm, electrons will move away from the parent molecule after tunnelling and undergo decoherence on a 10-fs time scale. At the beginning of tunneling the electrons will be more delocalized and will collapse to a certain position within a time scale of ~1 ps, and then slowly diffuse or recombine with holes on longer time scales. For the strong excitation case, hot electrons may also be formed. When a hot electron is localized to a particular water molecule, it triggers the breaking of O-H bond.<br>When an electron ionizes away, it leaves a hole. The hole will be localized on water molecule within 10 fs, and will trigger subsequent processes such as proton transfer and coherent oscillations. In particular, after the hole is localized and before the proton transfer, there is a brief appearance of the metastable H<sub>2</sub>O<sup>+</sup> ion, whose lifetime is experimentally captured and is predicted to be 46± 10 fs. The nuclear quantum effect in this process plays a key role.<br>Using methods such as real time-time dependent density functional theory (rt-TDDFT), it has been found that water undergoes plasmonization under intense laser pulses corresponding to field strength amplitude larger than 2.4 V/Å. The effective electron temperature during this period reaches over 20,000 K. Strongly excited water in this state exhibits behaviors of a liquid metal, and extremely strong nonthermal and nonadiabatic effects. In the process of plasmonization, a large fraction of chemical bonds in water molecules are broken and reorganize themselves, and many chemical species such as hydrogen molecules may appear, which also implies that laser-induced plasmonization could be used to synthesize new substances.<br>Although the previous works have brought about a very rich understanding, we have also found some details that still need to be explored: (i) In most theoretical calculations, the influence of nuclear quantum effects has not been taken into account, which may lead to the inadequate description and inaccurate prediction. (ii) Some of the microscopic details observed in simulations do not yet have a direct counterpart in experimental measurements. (iii) The current simulation of water plasmonization is for the local behavior under the spatially uniform external field, while in the real situation there are spatial inhomogeneity and energy flow, which urgently call for excited state dynamics simulations at a much larger scale.<br>With the development of laser technology, the integration of water science and ultrafast technologies will be increasingly strong, so we believe that such a systematic understanding will play a key role in the future. It is expected that new research efforts will continue to contribute additional understanding and spawn new technologies in this exciting research area.

Anisotropic Raman spectral analysis and laser output based on large-sized scheelite bismuth molybdate tungstate mixed crystals

This work presented the near decimeter-sized single crystal growth of Bi2Mo2.6W0.4O12 and the systematic analysis of its Raman spectral characteristics.

Analysis of the Principles and Applications of Ultra-intensity and Ultrashort Laser

With the development of laser technology, how to improve the output performance and peak power of lasers has become one of the hot directions of current research. This study analyzes the principles and applications of ultra-intensity and ultrashort pulse laser. It firstly outlines the development history of laser technology and the basic definition of ultra-intensity and ultrashort pulse laser. It also mentions the realization methods for generating ultra-intensity and ultrashort pulse lasers, such as mode-locked femtosecond oscillators and CPA-based femtosecond amplifiers. The paper describes the principles of CPA technique and emphasizes its importance in realizing high power ultrashort pulses. The paper discusses various applications of ultra-intensity and ultrashort pulsed laser and summarizes and discusses the major bottlenecks facing current and future ultra-intensity and ultrashort pulsed lasers and their possible solutions. The technical review in this paper aims to enhance the understanding of ultra-intensity and ultrashort pulsed laser and provide insights into the next phase of research exploration in ultra-intensity and ultrashort pulsed lasers.

Investigation on nonlinear absorption and optical limiting properties of Tm:YLF crystals

Nonlinear optical limiting has recently attracted significant attention, thanks to the continuous development of laser technology. In order to explore more potential functional materials, the spectral and nonlinear optical properties of yttrium lithium fluoride doped with thulium (Tm:YLF) crystals are reported. Absorption and emission spectra of Tm:YLF are measured, and the absorption peaks correspond to the energy transition of Tm3+. Nonlinear absorption measurements are performed on crystals with different thulium doping concentrations (2.0 %, 2.5 %, and 3.0 %). The Z-scan results indicate the presence of two-photon absorption processes at 1064 nm pulse laser. Additionally, we measured the nonlinear transmittance of Tm:YLF crystals with various thulium doping concentrations and lengths to evaluate their nonlinear optical limiting performance. For the 2.5 % doped Tm:YLF crystal with 20 mm length, the maximum transmittance at low laser intensity is 73.9 %, and the minimum transmittance at high laser intensity is 38.1 %. These experimental results suggest that Tm:YLF crystals may have potential as solid-state nonlinear optical limiting materials.

Recent Advances in Light Detection and Ranging: Optical Modulation Solutions and Novel Nanotechnologies

AbstractLight detection and ranging (LiDAR) sensor is widely recognized as a critical component for accurate perception. However, there are a host of challenges that impede their performance, including low spatial resolution, high costs, large size, low reliability, and susceptibility to interference. It is challenging to overcome these issues using a single LiDAR module, necessitating the need for a review of current LiDAR technologies. The paper commences by introducing the fundamental principles of various laser rangefinders and discussing the optical modulation technologies used to prevent interference and ghost images. Next, the paper delves into the latest developments in laser technology, with a focus on enhancing the switching rate, compliance with eye safety regulations, miniaturization, and improving stability. One highly promising innovation is the photonic crystal surface emitting laser (PCSEL), a novel light source that boasts high‐speed, small divergence angles, and high‐power output. Finally, the paper discusses the advancements made in non‐solid‐state scanning and solid‐state scanning, such as improving stability, increasing scanning angles, and optimizing the manufacturing of mechanical and micro‐electromechanical systems (MEMS). Additionally, the paper highlights the recent advancements in nanotechnology, specifically metasurface technology, which offers superior capabilities such as beam deflection, enhanced field‐of‐view (FOV), and dynamic modulation.

Study on thermal effects of high-power laser-coupled water jets and the influence on the stability of water jets

In water-guided laser technology, the stability of water jets is crucial to ensure the efficient transmission of laser energy. However, the thermal effects generated when high-power lasers are coupled with water jets are bound to impact the stability of the water jets, thus becoming a critical issue that restricts the development of high-power water-guided laser technology. In addressing this issue, this paper establishes a temperature model for coupling high-power lasers with water jets. Subsequently, with validation of the model's effectiveness through experimental data, simulations are conducted to analyze the temperature distribution within the water jet. During the simulation process, lasers with different parameters were coupled with water jets to analyze the temperature variation law of the water jets. Additionally, the maximum laser power coupled with water jets of different lengths was solved. Based on the calculated temperature values of the water jet, simulate the evolution of its profile over time when it has an initial temperature gradient. Simultaneously, perform a three-dimensional reconstruction of the obtained perturbed profile and conduct ray tracing to analyze the laser's transmission losses within the perturbed profile. Finally, high-speed cameras are utilized to capture the profile of the water jet, validating the laser-induced fragmentation behavior in the water jet. The research findings will provide a significant reference value for selecting laser parameters and controlling thermal effects in water-guided high-power technology.

Preparation of Bi2Te3 Based on Saturable Absorption System and Its Application in Fiber Lasers

Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology. Its pulse output can be divided into Q-switched and mode-locked. Achieving ultrashort pulse with narrower pulse duration and higher power is the focus of current research on mode-locked lasers. As an important component of fiber laser systems, saturable absorber (SA) can modulate losses in the optical cavity and generate pulses, enabling the laser system to achieve pulse output under long-term normal operating conditions better. Therefore, expanding the selection range of materials with better saturable absorption properties to improve the quality of pulse output is an important topic in current research. Here, the second generation topological insulator Bi2Te3 single crystal is prepared, and a ring fiber laser system is built with the Bi2Te3 SA. The mode-locked pulse with a pulse duration of 288 fs and a signal-to-noise ratio of 80.202 dB is realized. This result verifies that Bi2Te3, as a member of topological insulator, has good saturable absorption characteristics, and has broad prospects for the application research in lasers.

(SO3CF3)−: A Non‐π‐Conjugated Motif for Nonlinear Optical Crystals Transparent into the Deep‐Ultraviolet Region

AbstractThe search for new ultraviolet (UV) or deep‐UV nonlinear optical (NLO) crystals would greatly prompt the development of laser science and technology. As the NLO performance of these crystals is mainly determined by the anionic groups, herein the (SO3CF3)− group is highlighted as a promising non‐π‐conjugated NLO‐active motif with excellent deep‐ultraviolet (DUV) transmission and good NLO properties. First‐principles studies reveal that this group possesses the largest HUMO‐LOMO gap among the (SO4)2−‐based units, as well as a relatively large NLO response. The further experiments demonstrate that the CsSO3CF3 compound containing the (SO3CF3)− motif exhibits th UV cutoff edge below 200 nm and an NLO effect ≈0.8× KH2PO4, confirming the potentials of this new motif for UV and DUV NLO applications.

A semi-analytical method of three-dimensional dual-phase-lagging heat conduction model

With the development of picosecond laser technology, the dual-phase-lagging (DPL) model is more suitable to describe the heat transfer problem with micro-scale effect and micro-time effect. In this paper, a three-dimensional dual-phase-lagging heat transfer model for picosecond laser processing is established. Then Fourier transform (FT) and Laplace transform (LT) are used to derive the frequency response functions (FRFs) of the problem in the frequency domain, and the inverse Laplace transform (ILT) and discrete-convolution fast Fourier transform (DC-FFT) algorithm are used to solve the temperature field. The calculation accuracy of this method is verified and the effect of phase lag constants on temperature field is studied. The results show that the semi-analytical method has a high accuracy for solving the dual-phase-lagging heat conduction model, and the phase lag of heat flux will affect the heating rate in the heating stage, and the phase lag of temperature gradient will delay the formation of temperature field. The effect of phase lag constants on temperature-time history is investigated and the related phenomena are explained by using the two-step heat transfer theory. This semi-analytical method provides a new approach to solve the problem of three-dimensional dual-phase-lagging heat transfer.

Study of highly reflective ceramic glaze coating and laser irradiation effects

The rapid development and wide application of laser technology, together with the gradually increased output energy of lasers, pose a great threat to safety. Therefore, the demand for anti-laser is urgent. Highly reflective coatings can dissipate large incident laser energy through reflection. In this paper, zirconium silicate (ZrSiO4) highly reflective ceramic glaze coatings were prepared on both ceramic and metal substrates. Their macro and micro structure evolution treated at different heating temperatures were studied. The reflectivity of the coatings was on average 85% over the range of 400 and 2400 nm and reaches a maximum of 94% at 1064 nm. The coatings on ceramic substrates showed good stability when irradiated under high-energy continuous laser with power density of 2000 W/cm2 for 60 s. On the other hand, the coatings prepared on metal substrates formed a layer of dense, glaze-like material after high-energy continuous laser irradiation with power density of 500 W/cm2 for 10 s or 1000 W/cm2 for 5 s, demonstrating good anti-laser performance.

Investigation of active laser delivery and antimycotic activity of zinc-containing nanomaterials and photodynamic drugs in the treatment of onychomicosis

One of the most common nail pathologies is onychomycosis, a fungal nail infection. The low efficiency of existing methods for the treatment of onychomycosis stimulates the search for new drugs and technologies for their delivery under the nail plate. The aim of the investigation was to study the possibility of using Er:YLF laser radiation for sequential laser microporation of the human nail plate and active laser delivery of modern photodynamic preparations and zinc-containing nanomaterials under the nail plate, as well as to determine their antimycotic activity against the Candida albicans fungus under photodynamic exposure with a wavelength of 656±10 nm. A 0.001 % aqueous solution of methylene blue, a chlorine-containing Revixan gel, as well as zinc-containing nanomaterials, which are aqueous solutions of polyvinylpyrrolidone gel with different concentrations of Zn(NO3)2 nanoparticles and acidity, were studied. It was established that the smallest number of laser pulses required for in vitro microporation of the nail plate and active laser delivery under the nail plate is required when using a 0.001 % aqueous solution of methylene blue, and the largest is required when using Revixan gel. For zinc-containing nanomaterials, an increase in the concentration of Zn(NO3)2 nanoparticles from 14 to 40 % leads to an increase in the number of laser pulses required for active drug delivery under the nail plate by 1.25 times, while a change in the acidity of the pH gel from 7.0 to 6.7 does not has a significant impact on it. It was found that all the studied drugs in combination with photodynamic action at a wavelength of 656±10 nm have an antimycotic effect on the Candida albicans fungus culture. The minimum growth rate of Candida albicans colonies was observed when using the Revixan gel, for which the antimycotic activity reached 73.8 %. The obtained results can be applied in the development of laser systems and technologies for the treatment of fungal diseases, including for photodynamic therapy of onychomycosis.