Femtosecond Pump-Probe Investigation of Ultrafast Phenomenon of GaAs

2013 ◽  
Vol 655-657 ◽  
pp. 851-854
Author(s):  
Dong Qing Yuan
Keyword(s):  
Femtosecond Laser ◽  
Thermal Equilibrium ◽  
Recombination Process ◽  
Scattering Process ◽  
Pump Probe ◽  
Strain Pulse ◽  
Delayed Time ◽  
Probe Investigation

The effect process between femtosecond laser and matter had been introduced first. Then introduce the theory of strain pulse and the experiment set up.We detect transient reflectivity change on surface of GaAs at different delayed time using femtosecond transient reflection spectroscopy.We found it was made up of three parts: original scattering process of 100fs, carriers-lattice thermal equilibrium of 1.5ps and recombination process of 500ps.

Ultrafast Relaxation Character of Nonequilibrium Carriers in GaAs Excited by Femtosecond Laser

2006 ◽  
Vol 532-533 ◽  
pp. 572-575
Author(s):  
Ming Zhou ◽  
Dong Qing Yuan ◽  
Li Peng Liu ◽  
Hui Xia Liu ◽  
Nai Fei Ren
Keyword(s):  
Femtosecond Laser ◽  
Relaxation Curve ◽  
Refraction Index ◽  
Free Carrier ◽  
Index Of Refraction ◽  
Lattice Temperature ◽  
Pump Probe ◽  
Recombination Lifetime ◽  
Carrier Effect ◽  
Carrier Recombination

Experiment setup of femtosecond laser pump probe was established, the time resolution of time-delay setting reached 67fs. By use of femtosecond laser with width of 30fs and wavelength is 796nm the dependence of transient change of reflectivity on delayed time in GaAs was measured by pump-probe method. By calculating the change of complex index of refraction (%n), free-carrier effect, lattice-temperature and carrier recombination contributions to relaxation curve was analyzed. When the carrier density N is 1.44×1018/cm3, free-carrier contribution to refraction index %nFC is -7.33×10-4, lattice-temperature %nLT is 0.85×10-4. Based on recombination rate equation, recombination lifetime of 980ps was deduced.

scholarly journals Understanding the Seeding Pulse-Induced Optical Amplification in N 2 + Pumped by 800 NM Femtosecond Laser Pulses

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 99
Author(s):  
Zhengquan Fan ◽  
Xiang Zhang ◽  
Qi Lu ◽  
Yu Luo ◽  
Qingqing Liang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Optical Gain ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Time Resolved ◽  
Optical Amplification ◽  
Pump Probe ◽  
Amplification Process ◽  
Energy Amplification

Nitrogen ions pumped by intense femtosecond laser pulses present an optical gain at 391.4 nm, evident by energy amplification of an injected resonant seeding pulse. We report a time-resolved measurement of the amplification process with seeding pulses having varying intensities. It is found that the amplification factor depends on the intensity of the seeding pulse and the effective temporal window for the optical gain becomes longer by applying more intense seeding pulses. These two features are in sharp contrast with classic pump-probe experiments, pinpointing the crucial role of macroscopic coherence and its dynamics during the lasing process. We further measure the temporal profile of the amplified emission for seeding pulse injected at different time delays. A complicated temporal behavior is observed, which highlights the nature of the superfluorescence.

scholarly journals Ultrafast pump-probe ellipsometry and microscopy reveal the surface dynamics of femtosecond laser ablation of aluminium and stainless steel

2020 ◽  
Vol 511 ◽  
pp. 145514 ◽  
Author(s):  
Jan Winter ◽  
Stephan Rapp ◽  
Maximilian Spellauge ◽  
Constanze Eulenkamp ◽  
Michael Schmidt ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Ablation ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Surface Dynamics ◽  
Pump Probe

Laser Ion Kinetics: Dynamics of Intramolecular Reactions in Substituted Benzalacetones

2000 ◽  
Vol 6 (2) ◽  
pp. 143-152 ◽  
Author(s):  
R. Heinicke ◽  
C. Grun ◽  
J. Grotemeyer
Keyword(s):  
Femtosecond Laser ◽  
Mass Spectrometer ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Photon Absorption ◽  
Single Shot ◽  
Pump Probe ◽  
Intramolecular Reactions ◽  
The Stability ◽  
Fragmentation Processes

Measurements of a single shot femtosecond laser pump-probe technique on substituted benzalacetones are reported. The technique is based on counter propagating femtosecond laser pulses in a supersonic beam of low density of sample molecules and simultaneous probe detection by ion or fragment ion formation through a reflectron time-of-flight mass spectrometer. It will be shown that the range of the pump-probe delays covers the time span between 100 fs and 10 ps depending on the pulse width of the laser used and the stability of the voltages of the mass spectrometer. The application of this technique to medium-sized organic molecules reveals some insight into the electron transfer process during ionisation through a 1 + 1 multi-photon absorption procedure. Furthermore it is demonstrated that this technique is also applicable to the investigation of ultra-fast isomerisation and fragmentation processes.

Femtosecond pump-probe investigation of primary stages of charge carrier generation in pure and Sn- and Ti- doped C60 films

2001 ◽  
Author(s):  
Sergey V. Chekalin ◽  
M. S. Kurdoglyan ◽  
Anatoly N. Oraevsky ◽  
N. F. Starodubtsev ◽  
Arkady P. Yartsev ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Carrier Generation ◽  
Pump Probe ◽  
Probe Investigation

Generation and Detection of Coherent Acoustic Pulses by Femtosecond Laser Pulses

2009 ◽  
Author(s):  
Chunlei Guo
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Dielectric Materials ◽  
Acoustic Oscillation ◽  
Femtosecond Laser Pulses ◽  
Acoustic Properties ◽  
Optical Pump ◽  
Pump Probe ◽  
Probe Technique ◽  
Dielectric System

In this paper, we systematically study the generation and propagation of coherent acoustic pulses in a metal-dielectric system using a two-color femtosecond pump-probe technique at different probe angles. A long-lived acoustic oscillation is observed in a borosilicate glass coated with gold and shows different attenuation and amplitude at different probe wavelength. Our study suggests that the two-color optical pump-probe technique can be utilized as a noninvasive tool to study acoustic properties of dielectric materials.

Effect of recombination process in femtosecond laser-induced modification on Ge crystal

2020 ◽  
Vol 29 (11) ◽  
pp. 114208
Author(s):  
Jia-Qi Ju ◽  
Zi-Yao Qin ◽  
Ju-Kun Liu ◽  
Hong-Wei Zhao ◽  
Yao-Qing Huang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Recombination Process
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