This PDF file contains the front matter associated with SPIE Proceedings Volume 10159, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

The paper is an introduction to the volume of proceedings and a concise digest of works presented during the XI^th National Symposium on Laser Technology (SLT2016) [1]. The Symposium is organized since 1984 every three years [2-8]. SLT2016 was organized by the Institute of Optoelectronics, Military University of Technology (IO, WAT) [9], Warsaw, with cooperation of Warsaw University of Technology (WUT) [10], in Jastarnia on 27-30 September 2016. Symposium Proceedings are traditionally published by SPIE [11-19]. The meeting has gathered around 150 participants who presented around 120 research and technical papers. The Symposium, organized every 3 years is a good portrait of laser technology and laser applications development in Poland at university laboratories, governmental institutes, company R&D laboratories, etc. The SLT also presents the current technical projects under realization by the national research, development and industrial teams. Topical tracks of the Symposium, traditionally divided to two large areas – sources and applications, were: laser sources in near and medium infrared, picosecond and femtosecond lasers, optical fiber lasers and amplifiers, semiconductor lasers, high power and high energy lasers and their applications, new materials and components for laser technology, applications of laser technology in measurements, metrology and science, military applications of laser technology, laser applications in environment protection and remote detection of trace substances, laser applications in medicine and biomedical engineering, laser applications in industry, technologies and material engineering.

Coherent light sources are one of the most fundamental research tools in biology, technology and in other areas. Synchrotron light source consists of a few basic parts: energy source – which is an electron beam accelerator, energy converter between electron and photon beams – which is an undulator, and photon user experimental lines. Each of these parts is separately a complex system, which is currently a subject to fast technological development. Future light sources of the fifth generation are based on completely new solutions of these fundamental parts, in comparison with the sources of the previous generations. Energy source is a new generation laser – plasma accelerator with electrical field in the area of multiple GV/m. A miniature undulator is tested in the MEMS technology from new materials. Classical light beam lines, vacuum, and difficult for management and beam distribution, change their meaning in the case of availability of miniature undulators positioned immediately at or even inside the experimental stations. After an introduction concerning the light sources of the previous generations, the article shows current research efforts on the mentioned key components of the fifth generation light sources. In some cases this is a continuation and modernization of the previous technologies, in the majority it is a brave endeavour to apply completely new technologies, like laser – plasma acceleration.

A detailed study of a Tm:YAP laser in continuous-wave (CW), single-pass end-pumped by a 793 nm diode laser is presented. The laser based on c-cut 3 at. % Tm:YAP crystal was experimentally examined and presented in the dependence on transmittance and radius of curvature of output coupling mirrors. A detailed spectral analysis was presented. The influence of a heat-sink cooling water temperature on the laser performance was studied. At room temperature, for an output coupling transmission of 19.5%, the maximum CW output power of 4.53 W was achieved, corresponding to a slope efficiency of 41.5% and an optical-to-optical conversion efficiency of 25.7% with respect to the incident pump power, respectively. We have shown that the output spectrum at a certain wavelength (e.g. 1940 nm) for a given pump power can be realized via the change of resonator parameters (OC transmittance, mode size).

On the basis of thermally bonded Er,Yb:glass/Co:MALO microchip a laser head pumped by fiber coupled laser diode was designed. The performance of the laser head were investigated and the main output parameters were determined. The energy over 40 μJ in 3.8 ns pulse with repetition rate of 0.735 kHz was achieved. The laser head characterized by such parameters can successfully be used in tele-detection applications.

An all-fiber, diode-pumped, continuous-wave Tm³⁺-doped fiber laser operated at a wavelength of 1.94 μm was developed. 37.4 W of output power with a slope efficiency as high as 57% with respect to absorbed pump power at 790 nm was demonstrated. The laser output beam quality factor M² was measured to be ~1.2. The output beam was very stable with power fluctuations <1% measured over 1 hour. The laser system is to be implemented as a scalpel for surgery of soft biological tissues.

We report our observations of both fundamental and bound soliton states generated in all-polarization maintaining (all-PM) fiber laser mode-locked by graphene saturable absorber. The laser can generate fundamental soliton pulses with 312 fs duration, centered at 1560 nm. For higher pumping power the laser operates in bound soliton state. Stable 460 fs pulses with equal intensities and 9.4 pulse-to-pulse separation.

Different structures of nitride Vertical-Cavity Surface-Emitting Lasers (VCSELs) have been developed in recent years. However there is still many problems with such constructions, especially with electrical and optical confinement, current injection and construction and fabrication of mirrors. In this paper we present novel approach to nitride VCSEL designing. We investigated structure with tunnel junction (TJ) and top and bottom dielectric distributed Bragg reflectors (DBRs). Using our three-dimensional self-consistent model we investigated thermal and electrical properties of such laser. We also proposed replacing bottom DBR by monolithic high contrast grating mirror (MHCG) and presented optical properties of VCSEL with such mirrors.

A comparative study of photoionized plasmas created by soft X-ray (SXR) and extreme ultraviolet (EUV) laser plasma sources was performed. The sources, employing high or low energy laser systems, utilized double-stream Xe/He gas-puff targets irradiated with laser pulses of different parameters. The SXR/EUV beams were used for irradiation of a gas stream, injected into a vacuum chamber synchronously with the radiation pulse. Photoionized plasmas produced this way in Ne gas emitted radiation in the SXR/EUV range. The corresponding spectra were dominated by emission lines originating from singly charged ions. Significant differences between spectra obtained in different experimental conditions concern specific transitions in Ne II ions. Creation of photoionized plasmas by SXR or EUV irradiation resulted in K-shell or L-shell emissions respectively. In case of the low energy system absorption spectra were measured additionally. In case of the high energy system, the electron density measurements were performed by laser interferometry, employing a femtosecond laser system. A maximum electron density reached the value of 2·10¹⁸cm^-3. For the low energy system, a detection limit was too high for the interferometric measurements, thus only an upper estimation for electron density could be made.

Laser radiation is used, among others, for surface treatment of various materials. At the Institute of Optoelectronics, under the direction of the late Professor Jan Marczak, a number of works in the field of laser materials processing were performed. Among them special recognition deserves flagship work of Professor Jan Marczak: implementation in Poland laser cleaning method of artworks. Another big project involved the direct method of laser interference lithography. These two projects have already been widely discussed in many national and international scientific conferences. They will also be discussed at SLT2016.

In addition to these two projects in the Laboratory of Lasers Applications many other works have been carried out, some of which will be separately presented at the SLT2016 Conference. These included laser decorating of ceramics and glass (three projects completed in cooperation with the Institute of Ceramics and Building Materials), interference structuring medical implants (together with the Warsaw University of Technology), testing the adhesion of thin layers (project implemented together with IFTR PAS), structuring layers of DLC for growing endothelial cells (together with IMMS PAS), engraving glass for microfluidic applications, metal marking, sapphire cutting and finally the production of microsieves for separating of blood cells.

The aim of the study was to investigate and compare photophysical properties of the most modern formulations used in the world – derivatives of: porphyrin, chlorines, bacteriochlorins, phthalocyanines and phenothiazines. Useful parameters of comparing the emission properties of various sensitizers groups are quantum yield of singlet oxygen generation (Φ_T) and quantum yields of fluorescence (Φ_F). The emission and excitation characteristics were appointed and shown as excitation – emission matrices (EX – EM). The influence of the monomerization degree of the pure hematoporphyrin (HP) on the quantum yield was also measured. Received quantum yield values of commonly used sensitizers are in the range 0.05 – 0.3 and efficiency values of singlet oxygen generation are 0.3 – 0.7. These values depend not only on the chemical structure of the compounds, but also on solvent polarity, temperature and concentration which is decisive for the monomerization degree.

The availability of low-cost therapeutic illuminators was one of the key factors to limit clinical use of PDT. The paper presents modern light sources which have revolutionized PDT method, contributing to its more common use. The technical parameters of different illuminators are compared. Finally, own light sources were presented and developed in Polish clinics.

Isolation of circulating tumor cells (CTCs) from the blood is important in the diagnosis of malignant tumors and for monitoring therapeutic responses. The two main problems to be solved are extremely low CTCs numbers in the blood (average 1-10 CTC per 10 ml of whole blood) and the absence of one particular phenotype or genotype, which would allow for precise identification. Isolation of CTCs can be based on physical characteristics, e.g. the size of the cells (ISET, Isolation by Size of Epithelial Tumor cells) or the biological properties of these cells (the expression of specific proteins on their surface). In the IOE WAT the copper alloy microsieves with a pore diameter of 10.85 ± 0.89 μm designed for cell isolation by ISET method were produced. The microsieves with 100 000 pores with a 50 μm interval was made using precise, percussion laser drilling. The performance microsieves filtration was determined using fluorescent beads with three dimensions: 4 μm, 10 μm and 15 μm. Furthermore, the suspensions of cells lines from different types of tumor were used in the process of filtration. The efficiency of the cells filtration process was affected by lack of biocompatibility of the material used for the microsieves production as well as the roughness and porosity of the microsieves surface. Moreover, the diameter of the pores and the course of the filtration process were also significant.

Human mesenchymal stem cells (hMSCs) with their vast differentiation potential are very useful for cell-based regenerative medicine. To achieve sufficient numbers of cells for tissue engineering, many different methods have been used to reach the effective increase of cell proliferation. Low-energy red light provided by light emitting diodes (LEDs) have been recently introduced as a method that promoted biomodulation and proliferation of hMSCs in vitro. The purpose of this study was to find the optimum stimulatory dosimetric parameters of LED (630 nm) irradiation on the hMSCs proliferation. The energy density was 2, 3, 4, 10, 20 J/cm² and the power density used was 7, 17 or 30 mW/cm². Human MSCs were irradiated with single or triple exposures daily at room temperature and the cell proliferation rate was evaluated during nine days after irradiation. The results showed that after irradiation 4 J/cm² and 17 mW/cm² at a single dose the proliferation rate of hMSCs increased on day 5 and 9 (13% and 7%, respectively) when compared to nonirradiated cells. However, triple LED irradiation under the same parameters resulted in the decline in the cell proliferation rate on day 5, but the proliferation rate was at the same level on day 9, when compared with the cell proliferation after irradiation with a single dose. The effect of a single dose irradiation with 4 J/cm² and 17 mW/cm² on the proliferation of cells was the highest when the cells were irradiated in phosphate-buffered saline (PBS) instead of MSCGM culture medium.

Autofluorescence (AF) is the natural emission of light by intrinsic fluorophores. Oxidized mitochondrial flavins, lipofuscin and reduced nicotinamideadenine dinucleotide phosphate (NAD(P)H) are the main sources of the autofluorescence in cells upon excitation with visible light. The aim of the study was to investigate changes in the metabolism of four cell lines by monitoring their autofluorescence with a microplate reader. Autofluorescence intensities of cells were collected at two wavelengths for the excitation and fluorescence emission: for endogenous NAD(P)H at 366/450 nm, for the oxidized flavoproteins and lipofuscin at 460/540 nm. Human mesenchymal stem cells (hMSC), epithelial cells from mammary gland (MCF 10A), breast ductal carcinoma (T-47D) prostate carcinoma (DU-145) were observed daily for 16 days. The level of NAD(P)H autofluorescence did not differ among the cell lines investigated. The significant increase in oxidized flavoproteins fluorescence intensity was recorded for hMSC and ranged from 140 to 175% of control. During 28 days differentiation process, the NAD(P)H, FAD and lipofuscin fluorescence intensities were recorded every day, and the redox ratio was then calculated. The redox ratio gradually decreased during the last eight days of osteogenesis and adipogenesis. Therefore, in our opinion the NAD(P)H, FAD, and lipofuscin fluorescence emission at the wavelengths selected are the optimal parameters to be collected during the differentiation process in order to monitor the metabolism of hMSC undergoing structural and morphological changes.

In the paper we describe a new construction and preliminary laboratory tests of airborne particle flow detector. The device is designed for continuous monitoring of biological particles in ambient air. The scattering and fluorescence signals from each particle are detected simultaneously. The device uses 375 nm laser for fluorescence excitation. The luminescence is measured with three broad bands. Principal Component Analysis was applied for data analysis. It has been demonstrated proper classification between various biological aerosols.

The newly developed pulsed/cw dermatological laser (with wavelengths 975 nm) is applied for therapies requiring deep penetration of tissue e.g. cutaneous (dermal) neurofibroma (Recklinghausen disease) or hemangiomas. As the selected eight patients had been treated previously using pulsed a Nd:YAG laser a comparison of these therapies was possible. The results of cutaneous neurofibroma therapy using diode laser show an improvement compared with the case of Ho:YAG and Nd:YAG laser therapies - however this should be checked for a larger number of patients.

Semiconductor emitters are used in many areas of medicine, allowing for new methods of diagnosis, treatment and effective prevention of many diseases. The article presents selected areas of application of semiconductor sources in UVVIS- NIR range, where in recent years competition in semiconductor lasers and LEDs applications has been observed. Examples of applications of analyzed sources are indicated for LLLT, PDT and optical diagnostics using the procedure of color contrast. Selected results of LLLT research of the authors are presented that were obtained by means of the developed optoelectronic system for objectified irradiation and studies on the impact of low-energy laser and LED on lines of endothelial cells of umbilical vein. Usefulness of the spectrally tunable LED lighting system for diagnostic purposes is also demonstrated, also as an illuminator for surface applications - in procedure of variable color contrast of the illuminated object.

Laser-induced periodic surface structures (LIPSS) can appear in different forms such as ripples, grooves or cones. Those highly periodic wavy surface features which are frequently smaller than incident light wavelength bring possibility of nanostructuring of many different materials. Furthermore, by changing laser parameters one can obtain wide spectrum of periodicities and geometries. The aim of this research was to determine possibility of nanostructuring pyrolytic carbon (PyC) heart valve leaflets using different irradiation conditions. The study was performed using two laser sources with different pulse duration (15 ps, 450 fs) as well as different wavelengths (1064, 532, 355 nm). Both low and high spatial frequency LIPSS were observed for each set of irradiation parameters. In case femtosecond laser pulses we obtained deep subwavelength ripple period which was even ten times smaller than applied wavelength. Obtained ripple period was ranging from 90 up to 860 nm. Raman spectra revealed the increase of disorder after laser irradiation which was comparable for both pico- and femtosecond laser.

The research-related tests aimed to determine the effect of filer-metal free laser beam welding on the structure and properties of 10 mm thick steel S700MC subjected to the Thermo-Mechanical Control Process (TMCP). The nondestructive tests revealed that the welded joints represented quality level B according to the requirements of standard 13919-1. The destructive tests revealed that the joints were characterised by tensile strength being by approximately 5% lower than that of the base material. The tests of thin foils performed using a high-resolution scanning transmission electron microscope revealed that filler metal-free welding led to the increased amount of alloying microagents (Ti and Nb) in the weld (particularly near fusion line) in comparison with welding performed using a filler metal. The significant content of hardening phases in the welds during cooling resulted in considerable precipitation hardening through finedispersive (Ti,Nb)(C,N) type precipitates (several nm in size) leading to the deterioration of plastic properties. The destructive tests revealed that the joints were characterised by tensile strength being by approximately 5% lower than that of the base material. The increase in the concentration of microagents responsible for steel hardening (Ti and Nb) also contributed to the decrease in weld toughness being below the allowed value of 25 J/cm².

Presented in this article are the results of experiments carried out to determine the causes of braze cracking of dissimilar materials brazed with a ROFIN DL 020 high power diode laser with the use of additional powdered EN AW-1070A aluminium alloy to bond thin aluminium sheets with soft, low alloy DC04+ZE75/75 steel plate which was electrolytically coated with zinc on both sides. Presented are the results of metallographic, macroscopic, microscopic, diffractometric phase analyses of the weld joints. Metallurgical problems arising during processing as well as suggestions regarding technical aspects of laser brazing dissimilar materials in regards to their physical characteristics and chemical composition are explored.

The absorption coefficient of the surface of a workpiece is of importance in laser treatment, particularly in the treatment where the temperature of an element must be strictly controlled. Laser surface treatment (such as hardening, metallic glazing) and laser forming can be primarily included in this type of technology. In another case, surface temperature must be precisely controlled, especially if structural changes are to be avoided. There are a number of ways to increase the absorption coefficient of the surface of an element. Since the laser forming is the research subject of the authors of the presented paper, it was necessary to determine the absorption coefficient for the different surfaces preparation of workpieces. Raw surface, oxidized surface, sandblasted surface, black enamel covered surface and waterglass covered surface were examined, respectively. The experiment was performed using a CO₂ laser with a head for a surface treatment which generates a rectangular beam of dimensions 2x20 mm, and the samples were made of X5CrNi18-10 stainless steel.

A laser cladding system consisting of a direct diode laser with the flat-top beam profile and an off-axis powder injection nozzle has been used to fabricate Co-based (Satellite 6) metal matrix composite coatings reinforced by spherical-shaped WC particles. Non-porous coatings with the WC fraction of about 50 vol.% and a low dissolution of the WC particles in the matrix have been obtained. The heat input level affects the degree of WC dissolution and the matrix mean free path between the embedded WC particles. Comparative erosion tests between the metallic Satellite 6 and composite Satellite 6/WC coatings showed that the composite coatings exhibit a superior erosion resistance only at the oblique impingement condition. Generally, a low erosion resistance of the composite coatings at the normal impingement is mainly attributed to a very smooth interface between the spherical-shaped WC particles and the matrix alloy.

The study presents preliminary results of theoretical analyses concerning interaction of quasi-cw laser radiation with an aluminium target. The range of laser power the authors were interested in was from 1 to 10 kW, and target thicknesses from 0.1 to 1 cm. It was also assumed that a laser beam diameter on the target (Al) was around 0.5 cm. A mathematicalphysical model of the phenomenon was based on the equation of conservation of energy (spatially one-dimensional model – (z,t)) taking into account: radiation absorption and transport inside the target, heat conduction, reflection of part of radiation from the target’s surface, and heat losses in the processes of melting and evaporation. Coefficients of light absorption and reflection from the target’s surface were described with semi-empirical expressions, which took into account their dependence on the temperature and density. Initially, a case of target static during heating was considered. Subsequently, the problem of enhancement of radiation interaction with the target (decrease of reflection coefficient) by the use of short (< 20 ns), high power pre-impulse was analyzed. The last case needed expansion of a set of equations with the continuity equation and the equation of motion, to take into account evaporation of target’s surface under influence of the pre-impulse. It was shown that thermal effect of the pre-impulse is practically not influencing final depths of target remelting. On the other hand, damage (matting) of the target’s surface by the pre-impulse, causing the decrease of reflection coefficient can have a substantial influence on the remelting depth.

The paper describes work connected to the investigation of the interaction of strong laser radiation with selected metals, constituting typical materials applied in military technology, like aluminum, copper, brass and titanium. A special laser experimental stand was designed and constructed to achieve this objective. The system consisted of two Nd:YAG lasers working in the regime of free generation (quasi-cw) and another Nd:YAG laser, generating short pre-pulses in the Qswitching regime. During the concurrent operation of both quasi-cw systems it was possible to obtain pulse energies amounting to 10 J in a time period (pulses) of 1 ms. The synchronized, serial operation resulted in energy amounting to 5 J over a time period (pulse) of 2 ms.

Variations of the target’s surface reflection coefficient, caused by the interaction of short pre-pulses with high power density were determined. The experiments were performed using a standard Nd:YAG laser with amplifiers, generating output pulses whose duration amounted to 10 ns and energy to 1 J, with near Gaussian profile.

Laser induced breakdown spectroscopy (LIBS) was used to analyze the emission spectra of targets under the conditions of the interaction of destructive strong and weak as well as long and short excitation laser pulses. A decay of the spectra in the UV range from 200 to around 350 nm was observed when irradiating the target with a long, quasi-cw destructive pulse. Moreover, in the case of an Al target, some AlO molecular spectra appeared, suggesting a chemical reaction of the aluminum atoms with oxygen.

In this paper the results of an experimental studies on nanosecond laser micromachining of selected materials are presented. Tested materials were thin plates made of aluminium, silicon, stainless steel (AISI 304) and copper. Micromachining of those materials was carried out using a solid state laser with second harmonic generation λ = 532 nm and a pulse width of τ = 45 ns. The effect of laser drilling using single laser pulse and a burst of laser pulses, as well as laser cutting was studied. The influence of laser fluence on the diameter and morphology of a post ablation holes drilled with a single laser pulse was investigated. The ablation fluence threshold (F_th) of tested materials was experimentally determined. Also the drilling rate (average depth per single laser pulse) of holes drilled with a burst of laser pulses was determined for all tested materials. The studies of laser cutting process revealed that a groove depth increases with increasing average laser power and decreasing cutting speed. It was also found that depth of the laser cut grooves is a linear function of number of repetition of a cut. The quantitative influence of those parameters on the groove depth was investigated.

SLM technology allows production of a fully functional objects from metal and ceramic powders, with true density of more than 99,9%. The quality of manufactured items in SLM method affects more than 100 parameters, which can be divided into fixed and variable. Fixed parameters are those whose value before the process should be defined and maintained in an appropriate range during the process, e.g. chemical composition and morphology of the powder, oxygen level in working chamber, heating temperature of the substrate plate. In SLM technology, five parameters are variables that optimal set allows to produce parts without defects (pores, cracks) and with an acceptable speed. These parameters are: laser power, distance between points, time of exposure, distance between lines and layer thickness. To develop optimal parameters thin walls or single track experiments are performed, to select the best sets narrowed to three parameters: laser power, exposure time and distance between points. In this paper, the effect of laser power on the penetration depth and geometry of scanned single track was shown. In this experiment, titanium (grade 2) substrate plate was used and scanned by fibre laser of 1064 nm wavelength. For each track width, height and penetration depth of laser beam was measured.

The paper presents the results of the process development of laser surface modification of commercially pure titanium with rhenium. The criterion of the successful/optimal process is the repetitive geometry of the surface, characterized by predictable and repetitive chemical composition over its entire surface as well as special mechanical properties (hardness and wear resistance). The analysis of surface geometry concluded measurements of laser penetration depth and heat affected zone (HAZ), the width of a single track as well as width of a clad. The diode laser installed on the industrial robot carried out the laser treatment. This solution made possible the continuous supply of powder to the substrate during the process. The aim of an investigation is find out the possibility of improving the tribological characteristics of the surface due to the rhenium alloying. The verification of the surface properties (tribological) concluded geometry measurements, microstructure observation, hardness tests and evaluation of wear resistance.

The paper presents selected results of model and technological experiments of welding iridium-platinum tips to spark plug electrodes. Variants of welding technology included different ways of preparing materials and the use of different Nd: YAG lasers (Rofin BLS 720 and Rofin Integral). The results of technological tests were verified by the metallographic evaluation of joints. Performance tests when powered by biogas were conducted for selected variants of welding.

Laser-assisted forming techniques have been developed in recent years to aid plastic working of materials, which are difficult in processing at normal temperatures due to a high brittleness, effects of high work-hardening or a high spring-back phenomenon. This paper reports initial experimental investigations and numerical simulations of a mechanically-assisted laser forming process. The research is aimed at facilitating plastic shaping of thin-walled parts made of high temperature resistant alloys. Stainless steel plate, 1 mm thick, 20 mm wide, was mounted in the cantilever arrangement and a gravitational load was applied to its free end. A CO₂ laser beam with rectangular cross-section traversed along the plate, towards the fixed edge. Laser spot covered the whole width of the plate. Experiments and simulations using the finite element method were performed for different values of mechanical load and with constant laser processing parameters. Experimentally validated numerical model allowed analysis of plastic deformation mechanism under the hybrid thermo-mechanical processing. The revealed mechanism of deformation consists in intense material plastic flow near the laser heated surface. This behavior results mainly from the tension state close to the heated surface and the decrease of material yield stress at elevated temperature. Stress state near the side edges of the processed plate favored more intense plastic deformation and the involved residual stress in this region.

The TiO₂ coatings were prepared by simple sol-gel method and modified by UV pulsed laser. TiO₂, also know as titania, is a ceramic compound, existing in numerous polymorphic forms, mainly as tetragonal rutile and anatase, and rhomboidal brookite. Rutile is the most stable form of titanium dioxide, whereas anatase is a metastable form, created in lower temperatures than rutile. Anatase is marked with higher specific surface area, porosity and a higher number of surface hydroxyl groups as compared to rutile. The unique optical and electronic properties of TiO₂ results in its use as semiconductors dielectric mirrors, sunscreen and UV-blocking pigments and especially as photocatalyst.

In this paper, the tetraisopropoxide was used as Ti precursor according to sol-gel method. An organic base was applied during sol preparation. Prepared gel was coated on glass substrates and calcined in low temperature to obtain amorphous phase of titania. Prepared coatings were modified by UV picosecond pulse laser with different pulse repetition rate and pulse power. Physical modification of the coatings using laser pulses was intended in order change the phase content of the produced material. Raman spectroscopy (RS) method was applied to studies of modified coatings as it is one of the basic analytical techniques, supporting the identification of compounds and obtaining information about the structure. Especially, RS is a useful method for distinguishing the anatase and rutile phases. In these studies, anatase to rutile transformation was observed, depending on laser parameters.

A compact size microscope based on nitrogen double stream gas puff target soft X-ray source, which emits radiation in water-window spectral range at the wavelength of λ = 2.88 nm is presented. The microscope employs ellipsoidal grazing incidence condenser mirror for sample illumination and silicon nitride Fresnel zone plate objective for object magnification and imaging. The microscope is capable of capturing water-window images of objects with 60 nm spatial resolution and exposure time as low as a few seconds. Details about the microscopy system as well as some examples of different applications from various fields of science, are presented and discussed.

Understanding the impact of gaseous pollutants on the earth's atmosphere, as well as more and more felt by mankind negative effects of its contamination, result in increasing the level of environmental awareness and contribute to the intensification of actions aimed at reducing the emission of harmful gases into the atmosphere. At the same time, the extensive studies are conducted in order to continuously monitor the level of air contamination with harmful gases and the industry compliance with the standards limited the amount of emitted pollutants.

Over recent years, there has been increasing use of cascade lasers and multi-pass cells in optical systems detecting the gaseous atmospheric pollutants and measuring the gas concentrations.

The paper presents the use of a tunable quantum cascade laser as a source of the IR radiation in an advanced detection system enabling the trace gaseous atmospheric pollutants to be identified. Apart from the laser, the main elements of the system are: a multi-pass cell, an IR detector and a module for control and analysis. Operation of the system is exemplified by measuring the level of the air pollution with ammonia, carbon oxide and nitrous oxide.

Allergic rhinitis, also known as hay fever is a type of inflammation which occurs when the immune system overreacts to allergens in the air. It became the most common disease among people. It became important to monitor air content for the presence of a particular type of allergen. For the purposes of environmental monitoring there is a need to widen the group of traditional methods of identification of pollen for faster and more accurate research systems.

The aim of the work was the characterization and classification of certain types of plant pollens by using laser optical methods, which were supported by the chemmometrics. Several species of pollen were examined, for which a database of spectral characteristics was created, using LIF, Raman scattering and FTIR methods. Spectral database contains characteristics of both common allergens and pollen of minor importance. Based on registered spectra, statistical analysis was made, which allows the classification of the tested pollen species.

For the study of the emission spectra Nd:YAG laser was used with the fourth harmonic generation (266 nm) and GaN diode laser (375 nm). For Raman scattering spectra spectrometer Nicolet IS-50 with a excitation wavelength of 1064 nm was used. The FTIR spectra, recorded in the mid infrared¹ range (4000-650 cm^-1) were collected with use of transmission mode (KBr pellet), ATR and DRIFT.

In this article we present the research on optoelectronic system for stand-off detection of alcohol vapours in moving cars. The idea of using commercially available cascade lasers was presented. Special attention was paid to the optical characteristics of the car windowpanes. It was shown that using 3.45 μm and 3.59 μm wavelengths the alcohol vapours inside a car can be successfully detected even for cars with different windows

The article presents the main aspects related to the development of nonconventional asymmetric laser data transmission system. It describes the principle of data transmission in both the direction away from the laser transmitter, wherein a pulse position modulation is used, and in the opposite direction, where the modulation of the reflected radiation is performed. The results presented in the article confirm the possibility of using the described technology in the civilian area for monitoring and telemetry, where devices without radiation sources are taken into account. In military applications, the system can be used to identify own objects and forces on the battlefield by the application of pulsed laser rangefinders which are currently a standard battle equipment.

Most of the current optical data transmission systems are based on continuous wave (cw) lasers. It results from the tendency to increase data transmission speed, and from the simplicity in implementation (straightforward modulation). Pulsed lasers, which find many applications in a variety of industrial, medical and military systems, in this field are not common. Depending on the type, pulsed lasers can generate instantaneous power which is many times greater when compared with cw lasers. As such, they seem to be very attractive to be used in data transmission technology, especially due to the potentially larger ranges of transmission, or in adverse atmospheric conditions where low power cw-lasersbased transmission is no longer feasible. It is also a very practical idea to implement data transmission capability in the pulsed laser devices that have been around and already used, increasing the functionality of this type of equipment. At the Institute of Optoelectronics at Military University of Technology, a unique method of data transmission based on pulsed laser radiation has been developed. This method is discussed in the paper in terms of both data transmission speed and transmission range. Additionally, in order to verify the theoretical assumptions, modules for voice and data transmission were developed and practically tested which is also reported, including the measurements of Bit Error Rate (BER) and performance vs. range analysis.

In this paper we present the DAVLL (Dichroic Atomic Vapor Laser Lock) signals detection method for laser frequency stabilization which has been improved by synchronous detection system based on the surface-stabilized ferroelectric liquid crystal (SSFLC). The SSFLC cell is a polarization switch and quarter waveplate component and it replaces the well-known two-photodiode detection configuration known as the balanced polarimeter. The presented polarization switching dichroic atomic vapor laser lock technique (PSDAVLL) was practically used in VCSEL-based frequency stabilization system with vapor isotopes (⁸⁵,⁸⁷Rb) rubidium cell. The applied PSDAVLL method has allowed us to obtain a frequency stability of 2.7 × 10⁻⁹ and a reproducibility of 1.2 × 10⁻⁸, with a dynamic range ratio (DNR) of detected signals of around 81.4 dB, what is 9.6 dB better than obtained in the balanced polarimeter configuration. The described PSDAVLL technique was compared with 3-f (on the 3rd harmonic) and passive frequency stabilization methods. Additionally, the presented setup consists only one-photodiode detection path what reduces parasitic phenomena like offsets between photodiode amplifiers, amplifier gain changes due to ambient conditions, aging effects of electronic components etc. as a consequence leads to better frequency reproducibility, stabilization accuracy and less detection system sensitivity to ambient condition changes.

This paper presents investigation of normal and cancerous tissue by the means of one and two photon fluorescence spectroscopy. A comparison those methods has been conducted, allowing for eventual determination of granting the best possible diagnostic results.

Measurement of vehicles speed by means of displacement measurement with "time of flight" lidar requires gathering of accurate information about distance to the vehicle in a set time interval. As with any pulsed laser lidar, its maximum range is limited by available incoming signal to noise ratio. That ratio determines not only maximum range, but also accuracy of measurement. For fast and precise measurements of speed of the vehicles their displacement should bee measured with centimeter accuracy. However that demand is hard to reach on long distances and poor quality of the echo signal. Improving accuracy beyond given by a single pulse probing requires emission of several probing pulses. Total displacement error will than fall with the square root of the number of executed measurements. Yet this method will not extend available distance beyond the limit set by threshold detection systems. Acquisition of the full waveform of received signals is a method that allows extension of maximum range through synchronic addition of subsequent waveforms. Doing so improves SNR by a well-known factor of square root of the number of carried additions. Disadvantage of this method is that it requires use of fast analog to digital converters for data acquisition, and simple distance calculation algorithms may not give the adequate accuracy due to relatively long sampling period of reasonable priced ADC’s. In this article more advanced algorithms of distance calculations that base on ADC raw data are presented and analyzed. Practical implementation of algorithm in prototype design of laser speed gun is shown along with real life test results.

The paper presents modifications of full-field optical methods commonly used to test the surface quality of optical components used for forming a high power laser beam and tests of a final wavefront. The modifications in reference to surface measurements rely on implementation of the novel fringe pattern processing methods including the quality improvement of initial interferogram and analysis of a reconstructed phase based on Hilbert-Huang transform aided by the principal component analysis. Also the Point Diffraction Interferometer as the efficient tool for high quality measurements of elements with high NA is introduced. In reference to a wavefront quality measurements two solutions are discussed: the use of a lateral shear interferometer and the system employing Transport of Intensity Equation method. The pros and cons for both methods are discussed.

The paper presents the new approach to the analysis of interaction between a high power laser beam and matter. The method relies on the combined experimental-numerical spatio-temporal analysis of temperature, displacement and strain maps which are generated at a surface of an object illuminated by a high power laser beam. Transient heat transfer numerical simulations were carried out applying the FVM, while the quasi-transient structural analyses were performed with the aid of the FEM. The displacement maps were captured by means of 3D Digital Image Correlation method, and temperature maps were provided by a high speed IR camera. The experimental data are compared to the initial model of laser induced heat transfer in an object and resulting displacements/strains. The first approach to hybrid experimental-numerical method which aims in indirect determination of laser beam profile is described. The monitoring of displacement/strain maps directly at an illuminated object may be also used for a structural integrity analysis of a target. In the paper at first the numerical simulations applied to model laser beam thermal interaction with solid bodies are presented. Next the laboratory experimental stand is described and the results of the initial tests performed at aluminum and bronze samples are shown and compared with numerical simulations. The advantages and disadvantages of the proposed methodology are discussed in relation to the two applications mentioned above.