Time Resolved Spectra of Raman and Thermal Emission During Pulsed Laser Heating of Silicon

1983 ◽  
Vol 23 ◽  
Author(s):  
D. Von Der Linde ◽  
G. Wartmann ◽  
M. Kemmler ◽  
Zhen-He Zhu
Keyword(s):  
Laser Heating ◽  
Thermal Emission ◽  
Crystalline Silicon ◽  
Laser Pulses ◽  
Low Frequencies ◽  
Time Resolved ◽  
Emission Time ◽  
Pulsed Laser Heating ◽  
Anti Stokes ◽  
532 Nm

ABSTRACTLaser heating of crystalline silicon is investigated with 10 ns laser pulses at 532 nm Raman spectra below the transition threshold show distinct shifts to low frequencies. The absence of line shifts at higher energy is due to a time resolution artifact. Temperatures evaluated from frequency resolved anti-Stokes/Stokes ratios are in agreement with the temperature estimated from line shifts, and provide clear evidence that the surface reaches the melting point. These conclusions are confirmed by independent measurements of the thermal emission. Time-resolved pyrometry also provides the temperature evolution of the liquid phase.

Raman Scattering with Nanosecond Resolution During Pulsed Laser Heating of Silicon

1982 ◽  
Vol 13 ◽  
Author(s):  
D. Von Der Linde ◽  
G. Wartmann ◽  
A. Ozols
Keyword(s):  
Phase Transition ◽  
Raman Scattering ◽  
Laser Heating ◽  
Crystalline Silicon ◽  
Silicon Crystal ◽  
Pulsed Laser ◽  
Lattice Temperature ◽  
Time Resolved ◽  
Pulsed Laser Heating ◽  
Anti Stokes

ABSTRACTWe present time-resolved measurements of spontaneous anti-Stokes and Stokes Raman scattering during pulsed laser heating of crystalline silicon. The time-evolution of the lattice temperature is determined from the measured anti-Stokes/Stokes intensity ratio. In a separate calibration experiment we measure the temperature dependence of the anti-Stokes/Stokes ratio of an oven-heated silicon crystal from 300 K up to 900 K. The phase transition occuring during laser heating is detected by monitoring the changes of the optical reflectivity during laser irradiation. Our data suggest that the phase transition occurs at a lattice temperature of ∼600 K.

Characterization of vapor and aerosol flows by photothermal methods

1986 ◽  
Vol 64 (9) ◽  
pp. 1121-1123 ◽  
Author(s):  
H. Sontag ◽  
A. C. Tam
Keyword(s):  
Laser Heating ◽  
Thermal Emission ◽  
Pulsed Laser ◽  
Mie Scattering ◽  
Beam Deflection ◽  
Photothermal Heating ◽  
Excitation Laser ◽  
Photothermal Methods ◽  
Pulsed Laser Heating

Pulsed laser heating is used to label aerosols or absorbing vapors in a flow. In an absorbing vapor, the photothermal heating creates a travelling thermal lens that can be detected by a probe-beam deflection scheme yielding information on flow velocity and the concentration of absorbing species. The absorption by volatile aerosols is detected by transient variation in Mie scattering caused by particle evaporation. In addition, the velocity of a single moving aerosol can be measured by monitoring its infrared thermal emission induced by an excitation laser beam.

Calculation of Carrier and Lattice Temperatures Induced in Si and GaAs By Picosecond Laser Pulses

1981 ◽  
Vol 4 ◽  
Author(s):  
A. Lietoila ◽  
J. F. Gibbons
Keyword(s):  
Crystalline Silicon ◽  
Variable Parameter ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Hot Carriers ◽  
Thermalization Time ◽  
Picosecond Laser Pulses ◽  
Carrier Temperature ◽  
Energy Relaxation Time ◽  
532 Nm

ABSTRACTA previously presented computer model was used to calculate melt thresholds and carrier temperatures in crystalline silicon and gallium arsenide subjected to picosecond laser pulses at 532 nm. The energy relaxation time of hot carriers was a variable parameter. For Si, a thermalization time of 1 ps yields results which are in very satisfactory agreement with published experimental data: the melt threshold is 0.19 J/cm2, and the maximum carrier temperature for the threshold pulse is 5500 K. The melt threshold in GaAs is substantially less, 0.03 J/cm2 for a thermalization time of 1 ps.

Pulsed Laser Heating-induced Surface Rapid Cooling and Amorphization

2008 ◽  
Vol 1066 ◽  
Author(s):  
Longzhang Tian ◽  
Xinwei Wang
Keyword(s):  
Laser Pulse ◽  
Laser Heating ◽  
Crystallization Process ◽  
Interatomic Potential ◽  
Laser Pulses ◽  
Amorphous Layer ◽  
Final Thickness ◽  
Pulsed Laser Heating ◽  
The Relationship ◽  
Melting And Solidification

ABSTRACTIn this work, hybrid atomistic-macroscale simulation is conducted to explore the crystallization process of Si surface in the situation of fast melting and solidification induced by ultrafast laser heating and heat conduction. Using the environment-dependent interatomic potential, samples containing 2,880 and 11,520 Si atoms are modeled to provide accurate details for the relationship between the finial crystal structure and the parameters of laser pulses. For different pulsed lasers, amorphous layers are found to form when the laser fluence exceeds a certain critical value. An empirical correlation Ec = 448.76 × (tg)0.56 is obtained to relate this critical fluence to the laser pulse width. It is found that the final thickness of amorphous layer is related to the fluence of the laser pulse with the same full width at half maximum (FWHM). Employing laser pulses with FWHM = 6.67 ns, the formation and recrystallization processes of a 12 nm thick amorphous layer is further investigated, which may have great potential in laser manufacture techniques for Si-associated structures.

scholarly journals Time-resolved, local temperature measurements during pulsed laser heating

2010 ◽  
Vol 12 (8) ◽  
pp. 083011 ◽  
Author(s):  
Ralf S Kappes ◽  
Chen Li ◽  
Hans-Jürgen Butt ◽  
Jochen S Gutmann
Keyword(s):  
Laser Heating ◽  
Pulsed Laser ◽  
Temperature Measurements ◽  
Local Temperature ◽  
Time Resolved ◽  
Pulsed Laser Heating

scholarly journals Time-Resolved Spectroscopy of Plasma Resonances In Highly Excited Silicon And Germanium

1985 ◽  
Vol 51 ◽  
Author(s):  
A. M. Malvezzi ◽  
C. Y. Huang ◽  
H. Kurz ◽  
N. Bloembergen
Keyword(s):  
Thermal Model ◽  
Near Infrared ◽  
Laser Pulses ◽  
Band Gaps ◽  
Strong Increase ◽  
Electron Hole ◽  
Time Resolved ◽  
Electron Hole Plasma ◽  
Silicon And Germanium ◽  
532 Nm

ABSTRACTThe dynamics of the electron-hole plasma in silicon and germanium samples irradiated by 20 ps, 532 nm laser pulses has been investigated in the near infrared by time-resolved picosecond optical spectroscopy. The experimental reflectivities and transmissions are compared with the redictions of the thermal model for degenerate carrier distributions through the Drue iformalism. Above a certain fluence, a significant deviation between measured and calculated values indicates a strong increase of the recombination rate as soon as the plasma resonances become comparable with the band gaps. These new plasmon-aided recombination channels are particularly pronounced in germanium.

scholarly journals Portable double-sided pulsed laser heating system for time-resolved geoscience and materials science applications

2017 ◽  
Vol 88 (8) ◽  
pp. 084501 ◽  
Author(s):  
G. Aprilis ◽  
C. Strohm ◽  
I. Kupenko ◽  
S. Linhardt ◽  
A. Laskin ◽  
...  
Keyword(s):  
Laser Heating ◽  
Materials Science ◽  
Pulsed Laser ◽  
Heating System ◽  
Time Resolved ◽  
Pulsed Laser Heating

scholarly journals Decomposing electronic and lattice contributions in optical pump-X-ray probe transient inner-shell absorption spectroscopy of CuO

2019 ◽  
Vol 205 ◽  
pp. 04015
Author(s):  
Johannes Mahl ◽  
Stefan Neppl ◽  
Friedrich Roth ◽  
Catherine Saladrigas ◽  
Hendrik Bluhm ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Laser Pulses ◽  
Temperature Dependent ◽  
Optical Pump ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption ◽  
532 Nm

Electronic and lattice contributions to transient X-ray absorption spectra of CuO are analyzed using picosecond time-resolved and temperature-dependent measurements. Super-bandgap excitation with 355 nm and 532 nm laser pulses leads to significantly different trends.

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