scholarly journals An estimate of size of copper nanoparticles levitating over the melt surface using the measurements of spectral reflectance

2021 ◽  
Vol 2116 (1) ◽  
pp. 012060
Author(s):  
Leonid A Dombrovsky ◽  
Vladimir Ya Mendeleyev
Keyword(s):  
Laboratory Experiments ◽  
Copper Sample ◽  
Argon Atmosphere ◽  
Probe Laser ◽  
Spectral Measurements ◽  
Strong Decrease ◽  
Similar Time ◽  
Probe Laser Beam ◽  
Copper Melt ◽  
532 Nm

Abstract A strong decrease in normal reflectance of a probe laser beam of 660 nm wavelength reflected from the surface of copper sample just after the beginning of the sample melting in a rarefied argon atmosphere has been observed recently by the authors. A similar time dependence of the reflectance is obtained in the laboratory experiments of the present paper at the wavelengths of 532 nm. The additional spectral measurements enable the authors to estimate the size of condensed nanoparticles levitating over the copper melt.

scholarly journals Interaction of a Low-Power Laser Radiation with Nanoparticles Formed over the Copper Melt in Rarefied Argon Atmosphere

Thermo ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 1-14
Author(s):  
Leonid A. Dombrovsky ◽  
Vladimir Ya. Mendeleyev
Keyword(s):  
Laser Radiation ◽  
Sample Surface ◽  
Copper Sample ◽  
Argon Atmosphere ◽  
Solid Sample ◽  
Surface Pattern ◽  
Probe Laser ◽  
Light Pressure ◽  
Scattering Effects ◽  
Copper Melt

Two effects have been recently observed by the authors for the copper sample melted in a rarefied argon atmosphere. The first of these effects is a strong decrease in the normal reflectance of a copper sample with time just after the beginning of melting. A partially regular crystal structure was also formed on the surface of the solid sample after the experiment. Both effects were explained by generation of a cloud of levitating nanoparticles. Additional experiments reported in the present paper show that the rate of decrease in reflectance increases with pressure of argon atmosphere and the surface pattern on the solid sample after the experiment depends on the probe laser radiation. It is theoretically shown for the first time that the dependent scattering effects in the cloud of copper nanoparticles are responsible for the abnormal decrease in normal reflectance and also for the observed significant role of light pressure in deposition of nanoparticles on the sample surface. The predicted minimum of normal reflectance is in good agreement with the experimental value.

Different light and temperature requirements for survival and growth in three species of Kallymeniaceae (Rhodophyta) from the Mediterranean Sea

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Conxi Rodríguez-Prieto
Keyword(s):  
Laboratory Experiments ◽  
Culture Conditions ◽  
Initial Surface ◽  
Target Species ◽  
Strong Decrease ◽  
Maximum Value ◽  
Determining Factors ◽  
Temperature Requirements ◽  
Survival And Growth ◽  
The Mediterranean

Abstract Laboratory experiments have shown that light and temperature requirements are critical determining factors for thallus survival and growth of three Mediterranean Kallymeniaceae (Rhodophyta): Verlaquea lacerata, Croisettea requienii, and Meredithia microphylla, and explain their current bathymetric and habitat distribution. Verlaquea lacerata is annual and survived more than 1.5 years in culture, while C. requienii and M. microphylla are perennial and survived more than four and nine years in culture, respectively. The maximum survival was observed at 20–50 µmol photon m−2 s−1 and 10 and 12 °C within an 8:16 h light:dark regime for the three species, while a strong decrease in survival was observed at temperatures of 24 and 26 °C, indicating a weak tolerance to warming temperatures in the Mediterranean. The maximum value of the rate of daily marginal extension per initial surface area was similar in the three species: 0.017 day−1 for V. lacerata (10 °C/8:16 h light:dark regime/10 µmol photon m−2 s−1), 0.021 day−1 for C. requienii (18 °C/14:10 h light:dark regime/10 µmol photon m−2 s−1), and 0.017 day−1 for M. microphylla (12 °C/8:16 h light:dark regime/20 µmol photon m−2 s−1). The experiments permitted the establishment of culture conditions for the target species, and the successful culture of marginal fragments indicates the possibility of indefinitely maintaining the species in the laboratory for bioconservation purposes.

Enhancement of the thermal lens signal induced by sample matrix absorption of the probe laser beam

2002 ◽  
Vol 41 (27) ◽  
pp. 5814 ◽  
Author(s):  
Victor I. Grishko ◽  
Chieu D. Tran ◽  
Walter W. Duley
Keyword(s):  
Laser Beam ◽  
Thermal Lens ◽  
Probe Laser ◽  
Sample Matrix ◽  
Probe Laser Beam ◽  
Thermal Lens Signal

scholarly journals Времяпролетные характеристики лазерного факела при абляции мишени MnSi в атмосфере аргона

2018 ◽  
Vol 44 (6) ◽  
pp. 103
Author(s):  
О.А. Новодворский ◽  
В.А. Михалевский ◽  
Д.С. Гусев ◽  
А.А. Лотин ◽  
Л.С. Паршина ◽  
...  
Keyword(s):  
Distribution Function ◽  
Laser Radiation ◽  
Langmuir Probe ◽  
Velocity Distribution Function ◽  
Argon Atmosphere ◽  
Gas Pressure ◽  
Buffer Gas ◽  
Laser Torch ◽  
Ion Velocity Distribution Function ◽  
532 Nm

AbstractThe Langmuir-probe technique has been used to study the time-of-flight characteristics of a laser torch during MnSi-target ablation in vacuum and argon atmosphere by pulsed 532-nm laser radiation at 15-ns pulse duration. It is established that the amplitude of the signal of fast particles in the laser torch nonmonotonically depends on the buffer-gas pressure. Mechanisms determining this dependence of laser-torch characteristics on the pressure are considered. The influence of buffer-gas pressure on the ion-velocity distribution function is determined.

scholarly journals Dual-comb Photothermal Spectroscopy

2021 ◽  
Author(s):  
Qiang Wang ◽  
Zhen Wang ◽  
Hui Zhang ◽  
Shoulin Jiang ◽  
Yingying Wang ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Spectroscopic Method ◽  
High Sensitivity ◽  
Fast Response ◽  
Sample Volume ◽  
Small Sample ◽  
Probe Laser ◽  
Spectral Measurements ◽  
Photothermal Spectroscopy ◽  
Fine Resolution

Abstract Dual-comb spectroscopy (DCS) has revolutionized optical spectroscopy by providing broadband spectral measurements with unprecedent resolution and fast response. Photothermal spectroscopy (PTS) offers an ultrasensitive and background-free gas sensing method, which is normally performed using a single-wavelength pump laser. The merging of PTS with DCS may enable a new spectroscopic method by taking advantage of both technologies, which has never been studied yet. Here, we report dual-comb photothermal spectroscopy (DC-PTS) by passing dual combs and a probe laser through a gas-filled anti-resonant hollow-core fiber, where the generated multi-heterodyne modulation of the refractive index is sensitively detected by an in-line interferometer. As an example, we have measured photothermal spectra of acetylene over 1 THz, showing a good agreement with the spectral database. Our proposed DC-PTS provides new opportunities for broadband gas sensing with super-fine resolution and high sensitivity, as well as with a small sample volume and compact configuration.

Spatial Mapping of Transient Atomic Concentrations Using Acousto-Optic Deflection

1986 ◽  
Vol 40 (6) ◽  
pp. 863-868 ◽  
Author(s):  
Carmen W. Huie ◽  
Edward S. Yeung
Keyword(s):  
Laser Beam ◽  
Sodium Tungstate ◽  
Imaging System ◽  
Region Of Interest ◽  
One Dimension ◽  
Probe Laser ◽  
Spatial Mapping ◽  
Spatial Region ◽  
Probe Laser Beam ◽  
Transient Events

We report a new imaging system for obtaining spatially and temporally resolved atomic absorption profiles for transient events. This is based on an aconsto-optic beam deflector that scans the probe laser beam in one dimension repeatedly across the spatial region of interest. Scan rates of 10 µs durations essentially freeze the absorbing species in time to allow a spatial resolution of 0.06 cm over a 1.2 cm length. With the use of 2K of buffer memory and a digitization interval of 200 ns (12 bits), the time evolution can be followed up to a total of 400 µs. The capabilities are demonstrated in the study of atom formation in a laser-generated plume from a sodium tungstate surface.

scholarly journals Determine Dispersion Coefficient of 85Rb Atom in the Y–Configuration

2019 ◽  
Vol 35 (2) ◽  
Author(s):  
Nguyen Tien Dung
Keyword(s):  
Laser Beam ◽  
Dispersion Coefficient ◽  
Electromagnetically Induced Transparency ◽  
Laser Beams ◽  
Probe Laser ◽  
Frequency Detuning ◽  
Coupling Laser ◽  
85Rb Atom ◽  
Probe Laser Beam ◽  
Induced Transparency

Abstract: In this work, we derive analytical expression for the dispersion coefficient of 85Rb atom for a weak probe laser beam induced by a strong coupling laser beams. Our results show possible ways to control dispersion coefficient by frequency detuning and of the coupling lasers. The results show that a Y-configuration appears two transparent window of the dispersion coefficient for the probe laser beam. The depth and width or position of these windows can be altered by changing the intensity or frequency detuning of the coupling laser fields. Keywords: Electromagnetically induced transparency, dispersion coefficient.

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