PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.
We have carried out both numerical and experimental studies of amplification of a short pulse of HF non-chain laser by a chain reaction amplifier. A small aperture laser was used as the master oscillator and a large aperture (100 cm2) one was used as an amplifier. Both lasers were discharge initiated. Output pulse shape and energy have been studied as a function of discharge triggering delay and gas mixture composition. Obtained results show that, in spite of the known differences of both spectral and temporal characteristics of non-chain and chain lasers, it is possible to create a high power HF MOPA system with pulse duration less than 100 ns, technical efficiency above 10% and energy close to the one of the amplifier in free lasing mode.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The use of the pulsed inductive transverse discharge for an excitation of the gas lasers on the electronic transition of the
atoms and molecules was suggested. The excitation system and the discharge tube have been created to achieve the inductive transverse discharge. The inductive transverse discharge emission of rare gases and their mixtures with halogens in pressure range 1 - 450 tons was investigated. The generation on the electronic transitions of atoms Fl (703.75, 712.79 and 731.1 nm), Hel (587.5 and 667.8 nm), Nel (585.3 nm), An (750.4 nm) and excimer molecules of XeCl (308 nm), XeF (353 nm) and KrF (248 nm) have been obtained for the first time. The results of the experimental study of spectral, temporal and energetic parameters of inductive lasers developed are presented.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Characteristics of CW CO laser with supersonic gas flow are discussed. Radio frequency discharge CO overtone (V+2→V) lasing with output power 50 W was demonstrated with gas cooling due to supersonic expansion. The overtone lasing was observed on 9→7, 10→8 and 11→9 vibrational transitions within spectral range 2.6-2.7 μm. The laser active medium length was 10 cm. The small signal gain on the overtone transitions was estimated to be 0.1 m-1. Fundamental band (V+1→V) lasing was observed within 4.9 - 5.7 μm spectral range. In fundamental band output power 2.1 kW with efficiency 21% was obtained, with typical small signal gain being about 1 m-1. Modeling experiments on electron-beam sustained discharge facility were carried out at experimental conditions (gas pressure, temperature) corresponding to those of supersonic gas flow. Possibilities of supersonic overtone CO laser design improvement to obtain overtone lasing on highly excited vibrational transitions of CO molecule corresponding to the spectral range ~3-4 micron are discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The electric-discharge KrF-laser with inductive-capacitive discharge stabilization and a pulse repetition rate up to 4 kHz is developed. The multisectional discharge gap with length of 25 cm was formed by 25 pairs of anode-cathode plates. The narrow discharge width of ≤1 mm was realized. The buffer gases He and Ne with F2 as the donor of fluorine were used. The maximum laser energy was ≈6mJ by using Ne/Kr/F2 mixture at a total pressure of 1.6...3.2 atm. The maximum laser efficiency was ≈1.4%. For measuring of the gas flow velocity in discharge gap the original optical method is used. The maximum gas velocity in the working gap is 19 m s-1. The average output power of KrF laser is ≈12 W at the pulse repetition rate of 3...4 kHz. The relative root-mean-square deviation of the laser pulse energy is σ=2...3.8%. It was shown, that laser beam profile formation in a laser cavity essentially depends on a gradient of refractive index of the active medium Δn, was made by free plasma electrons. The value of a refractive index gradient at the KrF laser wavelength is grad n ≥ 10-5 cm-1.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The construction of a surface corona UV pre-ionized TEA CO2 laser is described and dependence of its average output energy of the laser to gas mixture, discharge voltage and repetition rate is investigated. The electric circuit diagram and geometry of the pre-ionization system are presented. Configuration of circuit has been designed to produce only impulsive voltage difference between the laser electrodes. Also, the triggering configuration of trigatron is prepared for fast operation to minimize the arc occurrence as much as possible. Some data of current, voltage, laser pulses and average output energy versus gas mixture and applied voltages are given. IR spectrometer is used for measurements of central output wavelength of the laser. Operation of the laser on two adjacent vibrational-rotational transitions of CO2 molecule has been observed that shows the ability of this laser for working on multi-line in a same time for special applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The results of experimental study of the pump intensity and active media parameters effect on output energy and efficiency of a discharge-pumped ArF (193 nm) excimer laser on a mixture of He:Ar:F2 are presented. It was experimentally shown that for the achievement of maximal output energy with maximal efficiency of an ArF excimer laser it is necessary to use an optimal pump intensity of 4.5-5.0 MW/cm3. To achieve such active media pump intensity the excitation scheme of the LC-inverter type has been used where the energy losses inside discharge circuit had been decreased. Using the pump intensity of 5.0 MW/cm3 in an active media of He:Ar:F2 - 79.7:20:0.3 at total pressure of 2.4 atm the output energy of 1.3 J at the total efficiency of 2.0% was obtained for the first time.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The construction of XeCl laser excited by e-beam is described and its radiation parameters are presented. Laser distinguishes from others lasers having similar radiation energy by the small weight and dimensions. Laser excitation fulfills the electron accelerator on base Marx generator with vacuum isolation. The experiments were performed using a gas mixture of Ar-Xe-HCl with pressure of 2-3 bar. A plane-plane lasers optical cavity was used. 120 J output with optical pulse duration ~250 ns (FWHM) on a wavelength of 308 nm have been extracted from 25 cm laser aperture. The heterogeneity of laser intensity distribution was within the limits of 10%.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The results of experimental study of the pump intensity and active media parameters effect on the output energy and total efficiency of a discharge-pumped KrCl (223 nm) excimer laser on a mixture of Ne:Kr:HCl are presented. It was experimentally shown that for the achievement of maximal efficiency of a KrCl excimer laser it is necessary to use optimal pump intensity. The value of the optimal pump intensity for the laser on the mixture Ne:Kr:HC1 was found to be
in the range of 5.0-5.5 MW/cm3. To achieve such pump intensity the excitation scheme of the LC-inverter type has been used where the energy losses inside discharge circuit had been decreased. Using the pump intensity of 5.5 MW/cm3 the
output energy of 700 mJ with the total efficiency of 1.0 % was obtained for the first time.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Design, construction and operation of a high repetition rate TEA CO2 laser is reported. Cooling and gas circulation systems of this small laser consist of a radiator based cooling with capacity of 300 cm3 and two 2700 rpm blowers, respectively. Cold water (-3°C) with 100 cm3/s was supplied and used for cooling. The gas circulation velocity between the electrodes was 6 m/sec. Energy of 65-25 mJ per pulse was recorded for repetition rate of 500 Hz and 1 KHz, respectively. It is shown that the output energy of this small scale pin array UV pre-ionized laser very much depends on discharge voltage and Nitrogen gas ratio in the laser gas mixture. For mixture of C02: N2: He≡1:1:4 and the discharge voltage of 16 KV, pulse energies varies from 65-30 mJ, at 100 Hz and 1 KHz repetition rates. At repetition rate more than 2 KHz
pulse energy reduces to less than half of the maximum energy. The FWHM of 100 ns was recorded.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A sealed CuBr laser was designed and constructed. He and Ne were used as buffer gases; it is found that, under the same experimental conditions, the output power of laser increased significantly using Ne than He. We have also added a small amount of hydrogen in the tube, which generated excitation Pulses from 15 kHz. The influence of pulse repetition frequency (PRY) on the laser output power was studied. We have varied the PRF between 10 to 30 kHz by a control circuit and laser output power curve versus frequency has been achieved. The optimum frequency was obtained for maximum laser power. A minimum was obtained on the output power of laser versus PRF which can be attributed to acoustic frequencies of CuBr container structure. Maximum efficiency of this laser was about 0.8%.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Possible pairs of positive metal ions and negative ion of oxygen suitable for realization of efficient ion-ion recombination are considered. Predominantly populated by ion-ion recombination levels of several metal atoms are indicated. Possibility of population inversion creation and lasing on some transitions in metal atoms as well as development of efficient non-coherent radiation sources is discussed. Energy level diagrams illustrating positions of ii-resonances and transitions from the predominantly populated by ion-ion recombination levels are presented for 9 metal atoms.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Dependence of a CuBr laser output on the pressure of H2- and HBr- additives into active medium has been investigated. Optimal H2 and HBr densities for maximal laser output have been determined when pressure of Ne buffer gas was varied in the range from 10 up to 100 torr. Laser output has been studied with variation of the active compound (CuBr) pressure in the range from 0.1 up to 0.6 torr for gas discharge tubes of different volumes. The optimal additive pressure has been shown to linearly depend on a voltage across gas discharge tube at high pressure of the buffer gas. The
optimal density of copper bromide decreases while pulse repetition rate increases up to 100 kHz. It is assumed that accumulating of Cu-atoms takes place in the active medium due to decreasing of interpulse period.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Dye Lasers and Photoprocesses in Complex Organic Molecules
A method of fluorescent spectroscopy is used to study phototransformations of 4-methyiphenol and its NH2-substitutes in water excited by UV radiation of different sources. It is demonstrated that the photophysical and photochemical properties of these molecules depend on the electronic state to which they are excited.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The conditions of obtaining and spectral-luminescence properties of mixed Langmuir-Blodgett (LB) films of the new regular polyampholyte modified with octadecyl chains and two amphiphilic fluorophores (I and II - rhodamine dyes) were investigated. On the basis of conformational molecule analysis in force field MM2 the models of the dyes molecule and polymer repeat unit orientations at the water-air interface and LB films architecture have been offered. It was found
that dye aggregation took place in the densely packed multilayer films, which appeared in absorption and fluorescence spectra. Assumption was made about structure of aggregates. It was established that LB films, for which the ratio of dye and polymer was 17:83 mol%, had the highest fluorescence quantum yield.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Influence of excitation energy transfer in binary solid solution (<> in gelatin) on energy yield of photoproduct and diffraction efficiency of photochemical amplitude-phase light-induced grating is investigated. It is shown, that energy values necessary for photobleaching of eosin Y in mono and binary solutions are different. Their relative energy variation lies in the range 1,1-1,9 during all exposure time. Both the yield of photoproduct and diffraction efficiency of amplitude-phase light-induced grating can serve as the indicator of excitation energy transfer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The oscillator-amplifier of RB (Rodamin B) dye laser has been setup by using the second harmonic generation of Nd:YAG laser (15ns pulse duration, 35mJ maximum output energy) as a pump. The output energy of oscillator and amplifier were measured separately and the variation of amplifier dye concentration on the output energy was investigated. The above experiments were repeated for R6G (Rodamin 6G) and the results were compared with RB. By putting a convex lens in a proper place inside the RB dye oscillator resonator, the output power was increased by approximately 39%. Experimental results show good agreement with theoretical investigation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Spatial-time behavior of the main excited atomic and molecular excimer species were monitored with ns-gated ICCD camera (200-850 nm) and solar-blind PMT (115-300 nm) from spontaneous emission spectra of homogeneous volume discharge in high-pressure (up to 10 bar) argon. It is revealed, that broad (200-700 nm) UV-VIS continuum is caused
mainly by radiative recombination of free plasma electrons with Ar2+ ions. Emission intensities from this continuum and red Ar* lines have a typical recombination behavior in the afterglow stage of the discharge (square root of its intensity is proportional to the electron density). Observed UV-VIS continuum spectrum is modeling by free-bound photorecombination transitions to manifold of 4s, 4s, 4p, 4p, 3d, 3d Ar* levels. Peak intensity of the second continuum VUV emission from Ar2* excimers (126 nm) increases approximately quadratically with the gas pressure. This behavior is observed at pressure range of 1-2 bar, however at higher pressures the peak intensity has a tendency to the saturation. VUV emission from Ar2*1Σu+ (0) molecules increases during small-power secondary pumping pulses due to better mixing of singlet 1Σu+ and triplet 3Σu+ Ar2* states by additional electrons.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The given report is devoted to theoretical research of simultaneous lasing on two lines having common upper or lower level. It is shown that the competition can be two types: symbiosis (parallel lasing) and quenching. The competition by upper level is illustrated with simultaneous lasing on lines 724.5 and 703.2 nm of atom Ne in mixture Ne-Ar and lines 2.65 and 2.03 μm of atom Xe in mixture Ar-Xe. The competition by lower level is presented by lines 2.52 and 2.19 μm of atom Kr in mixture He-Ne-Kr and by lines 2.31 and 2.4 μm of atom Ar in mixture He-Ne-Ar.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Five temperature model is used to describe the process of the dynamics preferably in the transversely excited atmospheric-pressure (TEA) CO2 laser. In this paper five temperature vibrational dynamics and vibrational-rotational dynamics are analyzed and calculated. All physical constants and relaxation rates related to this model are examined. The laser pulse waveform can be calculated when varied laser's parameters. The output power and energy can be obtained from calculated intensity, it can provide theoretical basis for laser design. Theoretical arithmetic shows a good agreement with the experimental result.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The properties of runaway electron beams and X-ray radiation generated at a volume nanosecond discharge in atmospheric pressure air have been studied. The recent results available in this area have been analyzed. Physical nature of generation of runaway electron beams and X-ray radiation at a volume nanosecond discharge is under consideration.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Homogeneous volume discharge in high-pressure (up to 10 bar) argon is studied as a possible active medium for Ar2 VUV (126 nm) laser. Time dependences of the densities of Ar* (4s, 4p), Ar2* 4sσ a3Σu+ (v=0) were measured by the pulse dye laser absorption probing of the discharge plasma. Experimentally obtained temporal dependencies of several excited species are compared with calculated ones. Strong optical dynamic aberrations in the discharge plasma are observed for the probing laser beam. Nonuniform distribution of the pumping power density in the transverse cross section of the discharge is the reason of free electrons gradient. These phase aberrations are caused by negative contribution of free electrons to the refraction index.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This paper presents simulation results for three modes of pumping of a XeCl-laser under radiation pulse duration of 10, 30, and 50 ns. Temporal evolutions of pump power and laser radiation, energy of pumping and lasing, densities of electrons and HCI(i) molecules in the ground and vibrationally excited states have been simulated for each mode. Rate dependences ofthe processes of XeCl** excimer molecules formation, such molecules quenching by electrons and heavy
particles of plasma N(i), and induced radiation rate vs. time have been also obtained. For two modes of pumping with radiation durations of 30 ns and 50 ns, simulation data are compared with experimental results taken from the literature available. The simulated temporal evolutions of discharge current, radiation power, and lasing energy are in good agreement with the experimental results. There are no literature data regarding a laser with a pulse duration of 10 ns. The properties of laser operation at decreased pumping duration up to 10 ns are presented. Kinetic processes effect on radiant energy and laser efficiency has been analyzed. It follows from the analysis of calculation results that formation of excimer molecules takes place with high efficiency. Quenching processes of excimer molecules by electrons and heavy particles is the main factor leading to decrease in radiant energy, and therefore laser efficiency.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Influence of the discharge burning conditions on output radiation parameters and overall performance of a discharge pumped XeCl laser with pump pulse duration of 20 ns is experimentally investigated. It is shown that a 3.9 J/l•atm maximal specific output laser energy from the active medium is realized in the discharge consisting of the
strongly pronounced macro heterogeneities. Laser efficiency of a 2.7 % is reached at discharge current density of a 1.2-1.4 kA/cm2.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Theoretical investigation of the dependence of the transition probabilities on frequency and strength of an circular polarized electric field was carried out for a Kr atom. The number of regularities in the behaviour of these probabilities were revealed and investigated. It was shown that the transition probabilities for a Kr atom in a high-frequency discharge have cubic-polynomial dependence on the electric field strength. It was found, that an increase in the frequency of the electric field leads to a decrease in the splitting of the spectral lines in the electric field and decreases a sensibility of the transition probabilities to the electric-field strength. An anisotropy of the probabilities for transitions between Stark levels was investigated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The given work is devoted to the numerical research of lasing power for parallel and successive laser cells composing. In the report the approached formulas for calculation of lasing power in case of identical laser cells successive composition are found and the single channel with the transverse output of radiation is theoretically investigated. For carrying out the calculations for parallel combined multichannel system, the circuit of consecutive approaching is developed. Calculations for N ≤ 5 parallel combined sells for different parameters of the optical resonator and with a variation of losses on splitting mirror from 0 up to 5% are carried out.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Femtosecond and nanosecond lasers are used to produce oxide nanoparticles by laser ablation of steel. The deposition of those particles on the surface strongly modifies its properties. The aim of this study is the understanding of the nanoparticle formation. The dynamics of the plume expansion and of the nanoparticle deposition processes are investigated by means of in-situ time resolved optical analysis. Scanning electron microscopy and atomic force microscopy are used to characterise the particle film morphology deposited on the surface. The influence of laser parameters such as pulse duration (ns, fs), wavelength (UV, visible, IR) and background gas pressure (10 mbar - 1 bar) on the processes of nanoparticle formation is studied. It is shown that a high density plasma favours the particle formation, and that the high temperature of the plume obtained with nanosecond JR irradiation impedes the nanoclusters nucleation and prevents an efficient nanoparticle formation.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Experiments of laser-induced forward transfer (LIFT) have been performed using ultrashort laser pulses (800nm, 100fs). 40nm of Cr thin film have been transferred on glass and Silicon acceptor substrates in different conditions. The analysis of the deposits was carried out by optical and electronic scanning microscopy. An optimisation of the process has been carried out and a good resolution of the patterns was obtained. The dynamics of the plume has been monitored with a gated ICCD camera and the images analysis gave us indications on the transfer of the material.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
We present theoretical studies of polymethyl methacrylate (PMMA) ablation by single pulses of C02-laser radiation (9.17 μm) and by pulse trains of free-electron laser (FEL) operating in the wavelength range of 100-200 μm. Laser heating and vaporization of the PMMA sample and the mechanisms of ablation have been investigated for the particular experimental conditions. The theoretical description of laser-induced target heating and ablation is based on the widely used thermal model which allows one to describe mass removal over a fairly wide range of laser fluences from ablation threshold up to transition to phase explosion. It has been shown that, in contrast to metal ablation, PMMA ablation continues up to several milliseconds after laser pulse termination. Phase explosion aspects are analyzed on the basis of the target superheating data obtained by modeling. It has been demonstrated that, in the case of PMMA ablation, the pulsed regime of FEL can be modeled by continuous irradiation with the equivalent power. A methodology has been proposed to evaluate the absorption coefficients of PMMA for wavelengths of FEL, which are unknown at present, basing on the vaporization rate.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Laser processing of materials always was the important field for laser applications. Copper vapor laser (CVL) system are widely used in micromechanical engineering where optical system may provide high image quality. That allows us to concentrate the energy on a small surface and to produce very tiny holes and very thin cutting edges. The possibility to use "generator-amplifier" laser system (copper vapor elements LT-5Cu and LT-30Cu) for processing material without mechanical movements was investigated. As the pumping generator was used the scheme with the current pulse duration about 80 - 100 ns and the laser pulse duration may vary up to 25 ns. In the unstable resonator scheme the special plane mirror with reflecting coating was used. With the help of this system a number of materials were processed, namely: copper, stainless steel, gold, aluminum and nonmetals: sapphire, ceramics, various rocks, plastics etc.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The wavelength of CO2 laser radiation is in the spectral range of 9-11μm. So the rapidly tuning TEA CO2 laser is an ideal optical source and core parts of laser differential absorption lidar (LDIAL). To expand the spectrum of TEA CO2 laser and the amount of the atmospheric gases controllable by the LDIAL, laser spectrum of carbon-13 oxygen-16 isotopic species of carbon dioxide is investigated. The spectroscopic constants and wavelength of the two laser band 00011-10001 and 00011-10002 are calculated. Using the spectrum analyzer the spectrum of the TEA CO2 laser in which 13C1602 is used as working gas is obtained. The used laser is a rapidly tuning miniature TEA CO2 laser. The cavity of the TEA CO2 laser is 200 mm in diameter and 400 mm in length. The main electrodes are a pair of Chang's aluminum electrodes. Tuning mechanism consists of diffraction grating, trigger controller and high frequency stepping motor. The experimental wavelengths are in good agreement with the calculated data. Compared with common C02, the emission line range of 13C1602 is expanded toward the longer wavelength, the longest wavelength of the TEA 13C1602 laser is 11.347 μm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The problem of the gas ionization in the field of resonant laser radiation taking into account the radiation transfer is numerically solved. The free electrons are formed due to the mechanism of associative ionization. These electrons then collect energy through superelastic processes and initiate the avalanche ionization of the medium by electronic impact. An influence of resonant radiation transfer on kinetics of plasma formation on resonance transition of sodium atom with wavelength 589,6 nm is investigated.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
A high-speed system for controlling spectral and temporal parameters of copper vapor laser radiation was developed and studied. The laser is designed for medical applications, in particular, for photodynamic therapy and thermal destruction of pathological neoplasm formations. Repetition frequency of pulses and their on-off time ratio are synchronized by pumping pulses and can be independently controlled from a computer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
This presentation describes the results of the testing of the HYPERBEAM technology as a tool for rapid quality assurance of various complex surfaces. Developed by Hyperboloid LLC, HYPERBEAM technology is based on the use of a special light source (Hyperbeam) controlled by XY scanners of Cambridge Technology Corp. Data obtained in the testing confirmed that proposed method allows for rapid quality assurance of large complex surfaces with varying curvatures such as those of airplanes and marine vessels before the coating as well as the assessment of the visual uniformity of the coating layers.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Non-living dissolved organic matter (DOM) is the largest organic carbon pool in natural waters and plays a central role in the biogeochemistry of a variety of elements. Colloidal matter makes up a significant portion of the bulk DOM in aquatic environments, but is still poorly characterized. Fluorescence emission spectra excited at 270, 310 and 355 nm and absorbance values were measured for the colloidal fraction CF with particles size ranging between 5 and 200 nm, for the fraction F5 with molecules smaller 5 nm, and for DOM filtered with the 0.2 μm pore size filter. For all DOM fractions the "blue shift" of fluorescence maximum position was observed with excitation at 310 nm compared to excitation at 270 or 355 nm. With river water samples it was found that DOM contains about 40% of organic matter in colloidal fraction; that emission maximum wavelength is 5...10 nm longer for CF than for F5; that fluorescence quantum yield is decreasing in 12% for CF and increasing in 30% for F5 compared to the original DOM samples. We confirmed that bigger DOM nanoparticles have red-shifted fluorescence emission and lower fluorescence quantum yield compared to DOM nanoparticles smaller 5 nm.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Phototrophic purple sulphur bacteria represent an important constituent of coastal zone biota and a crucial link of sulphur cycling in the nature. Purple bacteria are widespread in the environment occurring almost in every water basin and also in soil. The spectroscopic research was performed in vivo on purple sulphur bacteria Chromatium sp. in different culture development stages and illumination conditions during culture growth. Possibilities of purple bacteria quantification in vivo using absorbance and fluorescence intensities are described. The experiments revealed the possibility of application of the intensities ratio of porphyrin pigments emission to cell blue fluorescence for the estimation of the culture physiological status. These findings may be used for improvement of remote sensing techniques of ecological monitoring.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Incoherent UV and VUV Sources and Laser Output Conversion
This paper describes the development of an intense xenon gas discharge UV flash-lamp. The emission of the flash-lamp is tailored to serve as a trigger for high voltage and current, photoconductive diamond switches. Xenon flash-lamps are broadly used for many applications, but have not been optimized at high currents (~10 kA), for short durations (<1 μs), and with emphasis on the UV spectral band of 220-250 nm. The diamond photoconductive switch requires trigger UV radiation in this band because it results in bulk and efficient absorption. We present the results of our flashlamp optimization, tailored for UV switching requirements of CVD diamond. The study's emphasis was on small diameter (≤10 mm), short A-K gap (0.5-5mm) xenon gas discharge lamps. Input electrical power on the order of 25MW was typical. Emission power, spectral energy distribution and their associated lamp efficiencies are presented. The optimization studies included variation of A-K gap, fill pressure, and driver current waveform, based on the dominant physics of the expansion of the gas discharge during sub-microsecond operation. Diamond response to UV exposure from xenon gas discharge lamps, in terms of bulk induced photoconductivity and induced charge carriers is discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Theoretical and experimental studies of low temperature plasmas of inert gas mixtures show a very high efficiency for energy transfer from broad vacuum ultravio let (VUV) continua to narrow spectra. The process of energy transfer can not be explained as an ordinary particle collision mechanism. Narrow band light amplification in plasmas of inert gas mixtures is discussed as a possible process of energy transfer.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The investigation results of the spectral-luminescent characteristics of rare gases He, Ne, Ar, Kr, and Xe and their binary mixtures He-Ne(Ar,Kr,Xe), Ne-Ar(Kr,Xe), Ar-Kr(Xe), and Kr-Xe under high pressures in the 740-1100 nm spectral range are presented. Excitation of gas media was carried out by uranium fission fragments. The information on the absolute intensities of the spectral lines belonging to the transitions of Nel, An, KrI, and XeI was obtained. The lines belonging to atomic transitions of 0, N, and C were also observed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Experimental results on peculiarities of bactericidal effect of atmospheric plasma components and narrowband ultraviolet (UV) radiation of barner discharge XeBr- and KrBr-excilamps on the cultures Escherichia coli and Staphylococcus aureus are presented. Combination of such plasma components as UV radiation at 190 < λ < 220 nm and electroneutral particles is shown to possess the best sterilizing action. A KrBr-excilamp is shown to possess the unique spectrum, which corresponds to maximum of DNA inactivation section of microorganisms.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
In the present work the opportunity of use of the emission with λ ~329 nm in Ar-Xe mixtures in radioisotope light sources is investigated. At excitation of this mixture by α-particles the transitions from a state Ar+(2P1/2)Xe (λ ~329 nm and ~508 nm) are observed only and there are no transitions from Ar+(2P3/2)Xe. Intensity (in photon/s) of 508 nm band is approximately in 17 times less than intensity of 329 nm band. Efficiency of a luminescence, the attitude of power of the emission in a band of 329 nm to the power enclosed in gas, makes about 5%. At use of α-sources helium collects, dependence of intensity of emission in a band of 329 nm from the pressure of helium in a mixture Ar-Xe-He is investigated. Rate coefficients of some two- and three-body reactions have been measured or estimated from experimental relations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Clinical efficiency estimation of XeCl-excilamp application for psoriasis curing in comparison with other methods of phototherapy for has been carried out for the first time. Curing psoriasis by XeCl-excilamp assistance is shown to be an effective and present-date method. Such a phototherapy advantages suggested are the good tolerance, and absence of intact skin irradiation. The use of chemicals is no longer relevant, and the total doze of irradiation happens to be rather low.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
The studies devoted to free-expanding and bounded discharges, taking place in a Xe flashlamp, have been carried out. With such a discharge bounded by the walls of a bulb the maximal UV radiation power density was ~ 700 kW/cm2 on the internal surface ofthe bulb and ~ 380 kW/cm2 on its external surface.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
Experimental time-amplitude and spectral characteristics of emission from B-X transitions of Xe*2 (λ = 172 nm), Kr*2 (λ = 146nm), and Ar*2 (λ = 126 nm) molecules excited by a dielectric barrier bounded pulsed corona discharge are presented as function of gas pressure, pulse repetition rate and average excitation power. In optimal experimental conditions emission efficiency of Xe and Kr dimers is 45-50% and 25-28%, respectively.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
At e-beam duration of 2-20 ns a shift of free-exciton line to the high-energy area in a pulsed cathodoluminescence spectrum of CVD diamond was observed. Such a shift had the higher value at the shorter e-beam duration. At ≈ 2 ns e-beam and a room temperature the free-exciton line was observed at 5.312±0.009 eV with the corresponding energy of wavevector-conserving phonon close to the energy of transverse acoustic phonon.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.