Optical Properties of Picosecond Laser Irradiated Graphite

1988 ◽  
Vol 100 ◽  
Author(s):  
A. M. Malvezzi ◽  
G. Reverberi ◽  
N. Bloembergen
Keyword(s):  
Optical Properties ◽  
Direct Evidence ◽  
Picosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Index Of Refraction ◽  
Transient Complex ◽  
Irradiated Graphite ◽  
Pump And Probe ◽  
Complex Index Of Refraction

ABSTRACTWe have employed pump-and-probe techniques coupled to ellipsometry to measure the transient complex index of refraction at 1.064 μm of higly oriented pyrolitic graphite (HOPG) interacting with 20 ps, .532 μm laser pulses. When the laser pump fluence exceeds the threshold value for melting, measurements indicate a substantial decrease of both real and imaginary parts of the index of refraction, thus confirming that molten graphite becomes less metallic. Measurements provide also direct evidence of the insensitivity of our picosecond results to evaporation from the irradiated surface.

Optical properties of amorphous hydrogenated carbon films: A spectroscopic ellipsometry study

1987 ◽  
Vol 2 (5) ◽  
pp. 645-647 ◽  
Author(s):  
Shuhan Lin ◽  
Shuguang Chen
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Carbon Films ◽  
Index Of Refraction ◽  
The Real ◽  
Complex Index ◽  
Tentative Explanation ◽  
Amorphous Hydrogenated Carbon ◽  
Ellipsometry Data ◽  
Complex Index Of Refraction

Optical properties of plasma-deposited amorphous hydrogenated carbon films were studied by spectroscopic ellipsometry. From the ellipsometry data, the real and imaginary parts, n and k, of the complex index of refraction of the film have been deduced for photon energies between 2.0 and 4.0 eV for as-grown as well as for thermally annealed films. Here n and k showed considerable variation with subsequent annealing, even under 400°C. A tentative explanation of the results is proposed.

Optical Properties of Metal Films and Their Silicides

1994 ◽  
Vol 337 ◽  
Author(s):  
M. Simard-Normandin ◽  
A. Naem ◽  
M. Saran
Keyword(s):  
Optical Properties ◽  
Optical Constants ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Metal Films ◽  
Index Of Refraction ◽  
Contact Method ◽  
Microelectronic Fabrication ◽  
Silicide Growth ◽  
Complex Index Of Refraction

ABSTRACTSilicides are used widely in microelectronic fabrication, yet there are very little data available regarding their optical constants at most wavelengths, and specifically at those of interest to G-line and I-line lithography. We have studied extensively the optical properties of Ti, Co, as metal films and as silicide films formed at various temperatures, and of CVD (chemical vapour deposition) W. Using spectroscopic ellipsometry at two angles of incidence, we have calculated the complex index of refraction N = (n, k) of these films every 10nm at 68 wavelengths between 230 and 900nm. These data are necessary to model accurately the reflectivity of wafers to study the effects of various thermal and surface treatments on silicide growth and to set exposure times for lithography. They also allow the use of reflectivity vs X as a non-contact method to map film thicknesses across wafers within the patterned devices themselves.

Magneto-optical properties of an optically pumped medium

1968 ◽  
Vol 46 (16) ◽  
pp. 1753-1761 ◽  
Author(s):  
M. Verschueren
Keyword(s):  
Optical Properties ◽  
Radio Frequency ◽  
Optical Radiation ◽  
Index Of Refraction ◽  
Optically Pumped ◽  
Frequency Shifts ◽  
Radio Frequency Radiation ◽  
Resonance Frequencies ◽  
Frequency Radiation ◽  
Complex Index Of Refraction

The magneto-optical properties of a system subject to an optical and a radio-frequency radiation are calculated. The frequency of both radiations is close to the resonance frequencies of the system and as such they have a strong effect on its properties. The frequency shifts induced by optical radiation are obtained. Relations between the complex index of refraction and the frequency shifts are discussed.

scholarly journals Динамика спинорной экситон-поляритонной системы в латерально сжатых GaAs микрорезонаторах при резонансном фотовозбуждении

2018 ◽  
Vol 60 (8) ◽  
pp. 1567
Author(s):  
А.А. Деменев ◽  
Н.А. Гиппиус ◽  
В.Д. Кулаковский
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Picosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Josephson Effects ◽  
High Q ◽  
Wide Range ◽  
Linearly Polarized ◽  
Polariton Branch

AbstractThe evolution of the spatial coherence and the polarization has been studied in a freely decaying polariton condensate that is resonantly excited by linearly polarized picosecond laser pulses at the lower and upper sublevels of the lower polariton branch in a high-Q GaAs-based microcavity with a reduced lateral symmetry without excitation of the exciton reservoir. It is found that the condensate inherits the coherence of the exciting laser pulse at both sublevels in a wide range of excitation densities and retains it for several dozen picoseconds. The linear polarization of the photoexcited condensate is retained only in the condensate at the lower sublevel. The linearly polarized condensate excited at the upper sublevel loses its stability at the excitation densities higher a threshold value: it enters a regime of internal Josephson oscillations with strongly oscillating circular and diagonal linear degrees of polarization. The polariton–polariton interaction leads to the nonlinear Josephson effects at high condensate densities. All the effects are well described in terms of the spinor Gross–Pitaevskii equations. The cause of the polarization instability of the condensate is shown to be the spin anisotropy of the polariton–polariton interaction.

scholarly journals Optical properties of humic-like substances (HULIS) in biomass-burning aerosols

2006 ◽  
Vol 6 (11) ◽  
pp. 3563-3570 ◽  
Author(s):  
A. Hoffer ◽  
A. Gelencsér ◽  
P. Guyon ◽  
G. Kiss ◽  
O. Schmid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Biomass Burning ◽  
Light Absorption ◽  
Fine Fraction ◽  
Solar Spectrum ◽  
Index Of Refraction ◽  
Complex Index ◽  
532 Nm ◽  
Complex Index Of Refraction

Abstract. We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass-burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure" calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65–0.0019i and 1.69–0.0016i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS at 532 nm was found to be quite low (0.031 and 0.029 m2 g−1 for the day and night samples, respectively). However, due to the high absorption Ångström exponent (6–7) of HULIS, the specific absorption increases substantially towards shorter wavelengths (~2–3 m2 g−1 at 300 nm), causing a relatively high (up to 50%) contribution to the light absorption of our Amazonian aerosol at 300 nm. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4–8.6%) are obtained, but those are still not negligible.

scholarly journals Optical properties of humic-like substances (HULIS) in biomass-burning aerosols

2005 ◽  
Vol 5 (4) ◽  
pp. 7341-7360 ◽  
Author(s):  
A. Hoffer ◽  
A. Gelencsér ◽  
P. Guyon ◽  
G. Kiss ◽  
O. Schmid ◽  
...  
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Biomass Burning ◽  
Amazon Basin ◽  
Fine Fraction ◽  
Solar Spectrum ◽  
Index Of Refraction ◽  
Complex Index ◽  
532 Nm ◽  
Complex Index Of Refraction

Abstract. We present here the optical properties of humic-like substances (HULIS) isolated from the fine fraction of biomass burning aerosol collected in the Amazon basin during the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate) experiment in September 2002. From the isolated HULIS, aerosol particles were generated and their scattering and absorption coefficients measured. The size distribution and mass of the particles were also recorded. The value of the index of refraction was derived from "closure'' calculations based on particle size, scattering and absorption measurements. On average, the complex index of refraction at 532 nm of HULIS collected during day and nighttime was 1.65–0.00187i and 1.69–0.00163i, respectively. In addition, the imaginary part of the complex index of refraction was calculated using the measured absorption coefficient of the bulk HULIS. The mass absorption coefficient of the HULIS was found to be quite low at 532 nm (0.031 and 0.029 m2g−1 for the day and night samples, respectively). However, due to the high Ångström exponent of HULIS (6–7) the specific absorption increases substantially towards shorter wavelengths m2g−1 at 300 nm), causing a relatively high (up to 50%) contribution to the absorption at this wavelength. For the relative contribution of HULIS to light absorption in the entire solar spectrum, lower values (6.4–8.6%) are obtained, but those are still not negligible.

Optical properties of a thin layer of the Vanadium dioxide at the metal state

2015 ◽  
Vol 9 (1) ◽  
pp. 2303-2310
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Optical Properties ◽  
Thin Layer ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Cost Of Energy ◽  
Infra Red ◽  
Metal State ◽  
The Cost ◽  
Reversible Phase

The vanadium dioxide VO₂ currently became very motivating for the nanotechnologies’ researchers. It makes party of the intelligent materials because these optical properties abruptly change semiconductor state with metal at a critical  temperature θ = 68°C. This transition from reversible phase is carried out from a monoclinical structure characterizing its semiconductor state at low temperature towards the metal state of this material which becomes tétragonal rutile for  θ ˃ 68°C ; it is done during a few nanoseconds. Several studies were made on this material in a massive state and a thin layer. We will simulate by Maple the constant optics of a thin layer of VO₂ thickness z = 82 nm for the metal state according to the energy ω of the incidental photons in the energy interval: 0.001242 ≤ ω(ev) ≤ 6, from the infra-red (I.R) to the ultra-violet (U.V) so as to be able to control the various technological nano applications, like the detectors I.R or the U.V,  the intelligent windows to  increase  the energy efficiency in the buildings in order to save the cost of energy consumption by electric air-conditioning and the paintings containing nano crystals of this material. The constant optics, which we will simulate, is: the index of refraction, the reflectivity, the transmittivity, the coefficient of extinction, the dielectric functions ԑ₁ real part and  ԑ₂  imaginary part of the permittivity complexes ԑ of this material and the coefficient absorption. 

Optical properties of the Vanadium dioxide

2015 ◽  
Vol 8 (2) ◽  
pp. 2148-2155 ◽  
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio
Keyword(s):  
Energy Efficiency ◽  
Optical Properties ◽  
Critical Temperature ◽  
Thin Layer ◽  
Dielectric Function ◽  
Vanadium Dioxide ◽  
Ultra Violet ◽  
Index Of Refraction ◽  
Practical Utility ◽  
Infra Red

The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature

Electric field probing by picosecond laser pulses

1992 ◽  
Vol 28 (12) ◽  
pp. 1137 ◽  
Author(s):  
A. Krotkus ◽  
V. Pašiškevičius
Keyword(s):  
Electric Field ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Picosecond Laser Pulses

scholarly journals Sputtering of Neutral Molecules and Molecular Ions From the Adenine Crystal Surface Induced by the UV Picosecond Laser Pulse

1982 ◽  
Vol 1 (1) ◽  
pp. 37-43 ◽  
Author(s):  
V. S. Antonov ◽  
V. S. Letokhov ◽  
Yu. A. Matveyets ◽  
A. N. Shibanov
Keyword(s):  
Laser Radiation ◽  
Kinetic Energy ◽  
Crystal Surface ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Molecular Ions ◽  
Laser Radiation Intensity ◽  
Ion Sputtering ◽  
Absorbed Energy ◽  
Picosecond Laser Pulse

This paper presents the results of observation of sputtering of neutral molecules and ions from the crystal adenine surface induced by fourth-harmonic Nd:YAG laser radiation with a pulse duration of 30 ps. The energy fluence of laser pulses was in the region (1–3) × 10−4 J/cm2. The kinetic energy distribution of the sputtered molecules spreads up to 0.7 eV. The experiment shows that the threshold of adenine molecular ion sputtering is connected with absorbed energy density in upper layers of the crystal surface but not by laser radiation intensity.

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