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With the development of laser technology, laser-driven proton acceleration provides a new method for proton tumor therapy. However, it has not been applied in practice because of the wide and decreasing energy spectrum of laser-accelerated proton beams. In this paper, we propose an analytical model to reconstruct the spread-out Bragg peak (SOBP) using laser-accelerated proton beams. Firstly, we present a modified weighting formula for protons of different energies. Secondly, a theoretical model for the reconstruction of SOBPs with laser-accelerated proton beams has been built. It can quickly calculate the number of laser shots needed for each energy interval of the laser-accelerated protons. Finally, we show the 2D reconstruction results of SOBPs for laser-accelerated proton beams and the ideal situation. The final results show that our analytical model can give an SOBP reconstruction scheme that can be used for actual tumor therapy.

Thin films play an important role in modern science and technology. With the development of optical fibre communication technology and laser technology, thin films are used more and more widely in this field. The application of optical film in optical communication and laser technology is introduced systematically. The application of optical films in optical communications basically covers a variety of conventional optical films. Based on this research background, the paper mainly analyses the optical and physical properties of zinc oxide nano-films and discusses its application in optical communication.

Recently, two-dimension transition metal carbides, carbonitrides, and nitrides called MXenes have attracted huge attention due to their outstanding physical properties in various fields. Here we highlight the enormous potential of MXenes as nonlinear optical materials in the laser technologies, which includes ultrafast laser pulse generation, laser frequency modulation based on four-wave mixing, and photonic diodes with time reversal symmetry breaking. Emphasis is placed on the wide spectral applicability of metallic MXene saturable absorbers in passively mode-locked femtosecond laser technologies, allowing for operation in the visible to mid-infrared range. The Z-scan analysis reveals that Ti3C2Tx MXene has a large nonlinear optical absorption coefficient and a negative nonlinear refractive index, and notably it also possesses the higher threshold for light-induced damage with 50% increase in nonlinear transmittance. The MXene/C60 stacked modules enable the achievement of nonreciprocal transmission of laser pulses for photonic rectification. We strongly believe that MXenes will play a significant role in advanced laser technologies such as optical information processing, molecular spectroscopy, and micromachining, while providing many insightful electro-optical applications.

Radially self-accelerating beams are rotating shape-invariant solutions of the Helmholtz equation. As such, they exhibit continuous indefinitely spiraling trajectories. Here we present the possibility to tailor those beams to achieve almost any desired beam cross section, without sacrificing the unique propagation characteristics. We discuss analytical tailoring opportunities and highlight their inherent limitations. Following that, by way of example, a genetic optimization algorithm is applied to demonstrate the feasibility of heuristic computer optimization methods in general. The convergence towards several test-targets is demonstrated and the influence of the chosen fitness function is discussed.

Photoacoustic (PA) is the phenomenon of changing optical power into acoustics (sound). Photoacoustic research continues to grow and have broader field of application, especially after the development of laser technology and the development of laser diodes. In the industrial era 4.0, PA research is increasingly developing, especially in the PA tomography topics or PA imaging which is widely applied in medicine, as well as in single molecular imaging research and the 3D imaging of body tissue system.

The objective of the paper is to apply the reverse engineering in the mechanical field to reconstruct the geometry of two types of model turbine blade: axial blade and Pelton bucket. To generate the point clouds, the geometry of the blades was scanned by laser and digital photogrammetry. The Creaform HandySCAN 700 laser scanner and VXelements software were used to get the point cloud of the blades. For digital photogrammetry the NIKON D610 photo device and Agisoft Photoscan software were used to get the point cloud of the blades. Finally, the point clouds generated were compared in GOM Inspect software to highlight the deviations between them.

With the continuous development of laser technology, more and more attention has been paid to the research of laser cleaning mechanism and the development of finished equipment. This paper introduces the application of laser cleaning technology in rust removal of iron and steel, summarizes the physical mechanism of laser cleaning, and puts forward the condition of synchronous cleaning and passivation of floating rust layer and the method of double beam wet cleaning and passivation. In addition, a cleaning method and device for wet cleaning and de-rusting with two beams is proposed in this paper.

With the introduction of DM laser technology, TDLAS gas detection techniques are realizing mass deployment. In this paper, we investigate signal processing techniques for TDLAS and introduce an equal weight sampling strategy to greatly reduce the data processing requirement. Theoretical analysis and experiments were conducted to investigate the sampling efficiency of such a sampling strategy, and concluded that the method can potentially reduce the noise by 11%.

Periodontitis is a multifactorial disease with complex inflammatory responses caused by the disruption of normal homeostatic processes by oral bacteria in the periodontal tissue. In periodontal therapy, the clinical-microbiological properties of the laser therapy may positively affect wound healing. This study involves extensive literature review to examine the antimicrobial impact of laser therapy on the progression of post-treatment periodontal tissue responses. The literature we reviewed was searched and compiled from Pub Med using the following terms: antimicrobial properties, laser technology, periodontal therapy, periodontitis, laser therapy, and periodontal wound healing. As per the literature review, the laser treatment exhibits antimicrobial activity, indicated by the decrease in biofilm formation and enhanced wound healing of the periodontal tissue. Laser technology is a recent approach employed for the management of periodontal disease. Various wavelengths are effective and have antibacterial effect. The comparison of different lasers and their effects on the periodontal tissue is difficult because of the availability of a wide range of treatment protocols for using laser.

MXenes, a new family of two-dimensional materials, were prepared by a selective chemical etching method and the saturation absorption characteristics were measured using the Z-scan method. At 1.06 μm, a passively Q-switched Nd:YAG ceramic laser was operated by using MXene Ti3C2T x as a saturable absorber successfully for the first time. At an absorbed pump power of 4.14 W, the pulse repetition rate was 186 kHz and the minimum pulse width was 359 ns. The maximal peak power and single-pulse energy were 2.04 W and 0.66 μJ respectively. This study demonstrates that MXenes show promise as saturable absorbers in laser technology.

Fulgurite is a natural glass created by lightning. Naturally it can be found at beaches or in deserts. Artificial fulgurite is created by immersing high-voltage electrodes in a tab of sand. Commonly, fulgurite is of interest among geoscientists, but its applications are still unknown. In the present paper, the concept of natural fulgurite generation is simulated to induce artificial fulgurite. Instead of lightning, a high-power laser beam is used as a source of transient heating. Syntactic sand from agrowaste is used as target material. Artificial fulgurite is generated after transient heating from a laser beam. The benefit of this finding can be used to extract silica from rice husk ash using laser technology.

The next generation of biological imaging modalities will be a movement towards super-resolution, label-free approaches to realize subcellular images in a nonperturbative, non-invasive manner and towards new detection metrologies to reach a higher sensitivity and dynamic range. In this paper, we discuss how the third generation femtosecond laser technology in combination with the already existing concepts in time-resolved spectroscopy could fulfill the requirements of these exciting prospects. The expected enhanced specificity and sensitivity of the envisioned super-resolution microscope could lead us to a better understanding of the inter- and intra-cellular molecular transport and DNA-protein interaction.

Micro-fabrication in transparent materials by femtosecond laser-induced modification of the optical properties inside transparent materials, preferentially optical glasses, has received much attention. Ultra short laser pulses are capable of inducing these modifications without cracking or even melting the glasses. This kind of modification, which appears as darkening inside glass relates to the trapped electrons or holes at defect sites in the glass matrix. The femtosecond laser technology allows controlling and modifying the optical properties of glasses on a sub-micrometer scale. Laser fluence and laser shot number are important parameters for femtosecond laser-induced modification of glasses. This paper presents the 800 nm femtosecond laser-induced optical modification inside soda lime glasses at different laser fluence levels and laser shot numbers. Modification thresholds at different applied laser fluences and shot numbers are measured. Pulse energy accumulation model is proposed to predict the behaviour of darkened area spots with applied laser fluence and shot numbers. Our experimental results and the pulse energy accumulation model are in good agreement.

Present weather sensors are becoming increasingly important as a means to augment networks of automated weather stations and extend the capability of manned observations. The classification of hydrometeors is one of the principal tasks that is addressed by present weather sensors. In this paper, we discuss a new laser-based technology for this purpose. The system improves upon current precipitation monitors by using a derivative of phase Doppler anemometry techniques to accurately determine particle speed and size. The instrument is also capable of distinguishing between liquid droplets and solid polycrystalline hydrometeors and can be used to estimate visibility. The incorporation of this technology into a meteorological station with other sensors, such as temperature and relative humidity probes, leads to the accurate classification of particle type. The example data shown are taken from tests in Leicestershire, England and Utah, USA and show the differences between solid and liquid precipitation events.

Optical clocks have demonstrated an improvement in temporal accuracy of several orders of magnitude over existing time standards based on caesium. Such systems hold great promise in many industrial sectors including financial time stamping, GPS-free navigation and network synchronisation. Such systems require a number of sophisticated lasers in a compact and reliable format for use outside of a laboratory environment, suitable for commercialisation and user transportation. Of particular interest, is emerging AlGaInN laser diode technology that has the potential to provide practical solutions for next generation optical clock technology.

An unconventional method for shape setting of NiTi shape memory alloy wires is proposed. A laser beam was used to induce straight shape, superelasticity and shape memory effects to thin NiTi wires. Laser treatment revealed to be a suitable and reliable alternative to the conventional final thermal treatment of NiTi wires, which is normally carried out in annealing furnaces. Thermo-mechanical and calorimetric tests showed that the laser heat treatment confers optimal functional properties, analogous to those of commercially available NiTi wires.

The recent development of laser technology and the large number of extreme laser experiments under construction renewed the research related to pair production in strong fields. If the predicted threshold of nonlinear QED is reached, pair production may be observed and the measurements must be compared with appropriate theoretical predictions. However the theoretical side still lacks the understanding of the relevant quantum processes including the effect of laser field parameters on the number and spectrum of created particles. We use the Dirac-Heisenberg-Wigner formalism to investigate the role of the pure electric inhomogeneity on the spectra of created pairs. This simplified model may also be relevant in high energy physics for the description of string fragmentation in the early stages of heavy ion collisions.

With the development of laser technology and related scientific fields, understanding of the structure–property relationships in nonlinear optical (NLO) crystals is becoming more and more important. In this article, first-principles studies based on density functional theory, and their applications to elucidate the microscopic origins of the linear and NLO properties in NLO crystals, are reviewed. The ab initio approaches have the ability to accurately predict the optical properties in NLO crystals, and the developed analysis tools are vital to investigating their intrinsic mechanism. This microscopic understanding has further guided molecular engineering design for NLO crystals with novel structures and properties. It is anticipated that first-principle material approaches will greatly improve the search efficiency and greatly help experiments to save resources in the exploration of new NLO crystals with good performance.

Professor Aleksandr Apollonovich Kazakov, a talented Russian scientist, outstanding organiser of research in laser technology and director of the Federal State Unitary Enterprise 'M.F. Stel'makh Polyus Research and Development Institute', died after a long and painful illness on 22 February 2012.

Inertial fusion research is approaching a critical milestone, namely the demonstration of ignition and burn. The world's largest high-power laser, the National Ignition Facility (NIF), is under operation at the Lawrence Livermore National Laboratory (LLNL), in the USA. Another ignition machine, Laser Mega Joule (LMJ), is under construction at the CEA/CESTA research centre in France. In relation to the National Ignition Campaign (NIC) at LLNL, worldwide studies on inertial fusion applications to energy production are growing. Advanced ignition schemes such as fast ignition, shock ignition and impact ignition, and the inertial fusion energy (IFE) technology are under development. In particular, the Fast Ignition Realization Experiment (FIREX) at the Institute of Laser Engineering (ILE), Osaka University, and the OMEGA-EP project at the Laboratory for Laser Energetics (LLE), University Rochester, and the HiPER project in the European Union (EU) for fast ignition and shock ignition are progressing. The IFE technology research and development are advanced in the frameworks of the HiPER project in EU and the LIFE project in the USA. Laser technology developments in the USA, EU, Japan and Korea were major highlights in the IAEA FEC 2010. In this paper, the status and prospects of IFE science and technology are described.

We have been studied the advanced Thomson scattering diagnostics from viewpoints of new concepts, laser technology and spectrum analysis. This paper summarizes results of development on technologies for advanced Thomson scattering diagnostics.

We demonstrate for the first time that human immunodeficiency virus (HIV) can be inactivated by irradiation with subpicosecond near-infrared laser pulses at a moderate laser power density. By comparing the threshold laser power density for the inactivation of HIV with those of human red blood cells and mouse dendritic cells, we conclude that it is plausible to use the ultrashort pulsed laser to selectively inactivate blood-borne pathogens such as HIV while leaving sensitive materials like human red blood cells unharmed. This finding has important implications in the development of a new laser technology for disinfection of viral pathogens in blood products and in the clinic.

It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. The laser involves exciting atoms and passing them through a medium such as crystal, gas or liquid. As the cascade of photon energy sweeps through the medium, bouncing off mirrors, it is reflected back and forth, and gains energy to produce a high wattage beam of light. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry, otolaryngology, gastroenterology, urology, gynaecology, cardiology, neurosurgery and orthopaedics. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This review will survey various applications of lasers in medicine including four major categories: types of lasers, laser-tissue interactions, therapeutics and diagnostics.

We demonstrate that nonlinear plasma waves driven by intense lasers in plasmas can act as relativistic mirrors. Compressed pulses with attosecond durations are predicted for currently available laser technology.

The Japanese Ministry of International Trade and Industry (MITI) has announced a new 10-year programme on Femtosecond Technology to begin next April. The programme will be directed by MITT's Electrotechnical Laboratory in Tsukuba and will bring together companies, other government labs and universities. The main themes of the programme will be femtosecond laser technology, materials, optoelectronics and ultrafast information transmission and measurements. Foreign researchers and companies will be welcome to join the project.

The development of a high-repetition-rate (rep-rate) electron-beam (e-beam)-pumped KrF laser is described. In this study, we aim to achieve pulsed laser outputs of 20 J/80 ns at a rep rate of 1 Hz. The key issues are heat management in the diode foils and introduction of long-lifetime switches into the pulsed-power system. E-beam generation experiments have been started with initial test results of twenty consecutive shots at 1 Hz. Improvement in the energy-transfer efficiency in the rep-rate pulsed-power systems is also discussed.

Despite the breathtaking progress of semiconductor diode laser technology in recent years there is still no such thing as a diode that emits blue light. A great deal of research effort is therefore being put into schemes for efficiently converting the near-infrared output from the best available diodes into green and blue coherent radiation. Recently Bill Kozlovsky and Bill Lenth of the IBM Almaden Research Center, California, USA, reported a result which represents the current high-water mark in this field. In collaboration with scientists at the IBM Zurich Research Laboratory they succeeded in generating 41 mW of blue laser light by using a nonlinear crystal to double the frequency of infrared radiation emitted by a GaAlAs diode laser (1990 Appl. Phys. Lett 56 2291).

A review is given of the papers presented at the All-Union Conference on Fast Optical Energy Conversion Processes in Photosynthesis, which was held on September 19–22, 1978 in Moscow. The main topics at this Conference were migration of excited states in photosynthetic membranes, mechanisms of electron transfer in the primary stage of photosynthesis, possibilities of utilizing laser technology in photobiological research, and theoretical aspects of electron transfer mechanisms in primary processes in photosynthesis. Thirty papers were presented at the Conference and of these six were given by specialists from outside the Soviet Union.

A theoretical analysis is made of the condition for the appearance of the negative photoconductivity, and its spectral characteristics are considered. An expression is obtained for the dependence of the photoelectron density on the frequency of the exciting light. It is shown that the photoconductivity spectra can be used to determine the dopant concentration. The negative photoconductivity may find applications in optoelectronics and other branches of semiconductor laser technology. Moreover, experimental studies of the negative photoconductivity spectra may give information on the validity of various models used in calculations of the laser gain in heavily doped semiconductors.

A review is given of technological developments and physical investigations relating to laser processing of thin films. It is pointed out that this application is one of the most promising in modern laser technology. Special attention is paid to special features of the action of laser radiation on thin-film objects and to general relationships governing the destructive effects. This is used as a basis for the formulation of the criteria which should govern the choice of the laser, optical system, and optimal characteristics of the laser beam.

A new laser method was developed for the fabrication of microoptic components, including large-aperture microlenses and microobjectives based on them. Such components can be used in fiber-optic communication lines, in integrated-optics devices, in laser technology, and in scanning optics. A description is given of a physical model of local laser sintering. The main types of microoptic components are listed and their characteristic parameters are given.

A study was made of the possibilities of using high-frequency capacitative discharges in laser technology. An analysis of the characteristics of such discharges showed that by using high-frequency discharges with a sufficiently large specific input energy one can substantially simplify the discharge chamber design in both diffusively and convectively cooled lasers.

Laser technology is being applied to clinical surgery with varying degrees of success. The author looks at those areas where lasers can offer a positive advantage, and also those where conventional surgery or treatment is still superior

The most important optical, thermal, and mechanical properties of KRS (TlBr-TlI and TlBr-TlCl) single crystals were determined. A method for measuring the linear absorption coefficient a and optical strength of these crystals was developed. Typical room-temperature values of a were in the range (6?10)?10?3 cm?1. The thresholds of the surface and bulk damage under the action of cw and pulse CO2 laser radiation were determined. The results indicated that thallium halides were promising materials for laser technology in the ? = 10 ? range.

The study of ultrashort laser pulses (USPS) has been a major activity within laser physics for nearly two decades. In the early years, the 'target' pulse duration was around 1 ps (=10−l2s), but as figure 1 shows, progress did not stop there; indeed, techniques described below have recently enabled pulses as short as 12 fs (= 12 x 10−15 s) to be generated.

A fusion power reactor can be fuelled practicably by injection of pellets accelerated by laser-produced ablation. The fuelling requirements of a demonstration fusion reactor can probably be met by present laser technology.

Although many meetings are held regularly to discuss laser technology and applications, the scientists and engineers working on the apparently mundane aspects of lamps rarely get together as a specialized group. In fact there is much to discuss, since after considerable research and development, several important new light sources have emerged in recent years.

A decade ago the cliche 'an answer in search of a problem' was applied to lasers. An interdisciplinary meeting on lasers in medicine held on 29 October 1975 exemplified the positive aspects of this cliche with laser and medical physicists reporting on the current state of laser technology and surgeons describing their requirements.