Time-Resolved Optical Studies of Picosecond Laser Interactions With Gaas Surfaces

1985 ◽  
Vol 51 ◽  
Author(s):  
J.M. Liu ◽  
A.M. Malvezzi ◽  
N. Bloembergen
Keyword(s):  
Picosecond Laser ◽  
Laser Pulses ◽  
Wavelength Dependence ◽  
Electron Hole ◽  
Molten Layer ◽  
Time Resolved ◽  
High Fluences ◽  
Electron Hole Plasma ◽  
Vapor Cloud ◽  
Melting Threshold

ABSTRACTThe interactions of picosecond laser pulses at 532 nm wavelength with GaAs surfaces have been studied with time-resolved reflectivity and transmission measurements at three probe wavelengths. At fluences below the melting threshold, the laser-generated electron-hole plasma is limited to a density below ≈1020cm−3. The high reflectivities of molten GaAs observed at fluences above the tlhreshold have a wavelength dependence inconsistent with a simple Drude model for a metallic GaAs molten layer. At high fluences, the evolution of a laser-induced vapor cloud is observed.

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.

Picosecond Photon-Solid Interaction

1984 ◽  
Vol 35 ◽  
Author(s):  
H. Kurz ◽  
N. Bloembergen
Keyword(s):  
Phase Transition ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Time Resolved ◽  
Electron Hole Plasma ◽  
Optical Heating ◽  
Main Emphasis ◽  
Firm Data ◽  
Heating Model ◽  
Recent Experimental Work

ABSTRACTSome of the fundamental aspects of pulsed laser interactions with semiconductors are reviewed within the frame of recent experimental work with picosecond laser pulses. Main emphasis is placed on data obtained in space-time resolved measurements of transmission and reflectivity of picosecond pulse irradiated silicon at different probing wavelengths. Four distinct interaction regimes can be defined, depending on the fluence of the laser pulse. Special attention is devoted to the phase transition from solid to liquid state at the surface. The optical heating model is found to be valid even on a time scale of picoseconds. Firm data of the electron-hole plasma density and lattice temperature are derived. The thermal nature of the phase transition is confirmed.

Robust single-mode lasers based on hexagonal CdS microflakes

2020 ◽  
Vol 8 (32) ◽  
pp. 11201-11208
Author(s):  
Yang Mi ◽  
Yaoyao Wu ◽  
Jinchun Shi ◽  
Sheng-Nian Luo
Keyword(s):  
Radiative Recombination ◽  
Single Mode ◽  
Whispering Gallery Mode ◽  
Radiative Recombination Rate ◽  
Electron Hole ◽  
High Quality ◽  
Time Resolved ◽  
Whispering Gallery ◽  
Electron Hole Plasma ◽  
Time Resolved Photoluminescence

We have achieved single-mode whispering-gallery-mode lasing in CdS microflakes with sharp linewidth (∼0.12 nm) and high quality factor (∼4200). Such lasers are superior to previous CdS lasers in these lasing parameters. Through time-resolved photoluminescence measurements, electron–hole plasma recombination is established to be the lasing mechanism. The radiative recombination rate of CdS microflakes is enhanced by a factor of ∼4.7 due to the Purcell effect.

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