scholarly journals Femtosecond Laser-Pulse-Induced Surface Cleavage of Zinc Oxide Substrate

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 596
Author(s):  
Xi Yu ◽  
Fumihiro Itoigawa ◽  
Shingo Ono
Keyword(s):  
Zinc Oxide ◽  
Femtosecond Laser ◽  
Pulse Energy ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Photon Absorption ◽  
Oxide Substrate ◽  
Bandgap Semiconductors ◽  
The One ◽  
Surface Cleavage

The induction of surface cleavage along the crystalline structure of a zinc oxide substrate (plane orientation: 0001) by femtosecond laser pulses (wavelength: 1030 nm) has been reported; a scanning electron microscope image of the one-pulse (pulse energy: 6–60 μJ) irradiated surface shows very clear marks from broken hexagons. This cleavage process differs from the general laser-induced melt process observed on the surfaces of narrower-bandgap semiconductors and other metal materials. This phenomenon is discussed using a multi-photon absorption model, and the pulse-energy dependence of the cleavage depth (less than 3 μm) is quantitatively analyzed. Laser-induced cleavage is found not to occur under multi-pulse irradiation; when more than four pulses are irradiated upon the same spot, the general laser-induced melt process becomes dominant. This cleavage–melt shift is considered to be caused by the enhancement of absorption due to the initial pulses, which is supported by our measurement of cathodoluminescence.

scholarly journals Nonperturbative generation of above-threshold harmonics from pre-excited argon atoms in intense mid-infrared laser fields

2017 ◽  
Vol 5 ◽  
Author(s):  
Guihua Li ◽  
Hongqiang Xie ◽  
Ziting Li ◽  
Jinping Yao ◽  
Wei Chu ◽  
...  
Keyword(s):  
Excited State ◽  
Femtosecond Laser ◽  
Pulse Energy ◽  
Laser Pulses ◽  
Infrared Laser ◽  
Femtosecond Laser Pulses ◽  
Probe Laser ◽  
Laser Fields ◽  
Mid Infrared ◽  
Highly Nonlinear

We experimentally investigate the generation of above-threshold harmonics completely from argon atoms on an excited state using mid-infrared femtosecond laser pulses. The highly nonlinear dependences of the observed signal on the pulse energy and polarization of the probe laser pulses indicate its nonperturbative characteristic.

Plasmon-Enhanced Two-Photon Absorption of Infrared Femtosecond Laser Pulses in Thin Gold Films

JETP Letters ◽  
2019 ◽  
Vol 109 (6) ◽  
pp. 382-386 ◽  
Author(s):  
S. I. Kudryashov ◽  
P. A. Danilov ◽  
S. G. Bezhanov ◽  
A. A. Rudenko ◽  
A. A. Ionin ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Photon Absorption ◽  
Gold Films ◽  
Two Photon Absorption ◽  
Two Photon

Femtosecond Laser Ablation of Zr55Al10Ni5Cu30 Bulk Metallic Glass

2007 ◽  
Vol 539-543 ◽  
pp. 1951-1954 ◽  
Author(s):  
Tomokazu Sano ◽  
Kengo Takahashi ◽  
Akio Hirose ◽  
Kojiro F. Kobayashi
Keyword(s):  
Laser Ablation ◽  
Metallic Glass ◽  
Femtosecond Laser ◽  
Bulk Metallic Glass ◽  
Pulse Energy ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ablation Depth ◽  
Polished Surface

Dependence of the femtosecond laser ablation depth on the laser pulse energy was investigated for Zr55Al10Ni5Cu30 bulk metallic glass. Investigation of the femtosecond laser ablation of bulk metallic glasses has not been reported. Femtosecond laser pulses (wavelength of 800 nm, pulse width of 100 fs, pulse energies of 2 – 900 μJ) were focused and irradiated on the polished surface of metals in air. The ablation depth of the metallic glass is deeper than that of its crystallized metal at a pulse energy in the strong ablation region. We suggest that the energy loss at grain boundaries of hot electrons which is accelerated by the laser electric field influence the ablation depth in the strong ablation region.

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.

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