Abstract
We investigated an early stage of laser-induced periodic surface structure (LIPSS) formation to elucidate the contribution of defects on the formation. 4H-SiC crystals were irradiated by multiple pulses of femtosecond laser with different laser spot sizes. We observed the decrease in formation thresholds of high-spatial-frequency LIPSS (HSFL) and lowspatial-frequency LIPSS (LSFL) with the increased irradiated laser spot size. For smaller laser spot size, HSFL was only formed at the periphery of LSFL formation area, whereas for larger spot size, HSFL was randomly distributed within the laser spot. Our results are coincident with the hypothesis that the existence of defects in crystal contributes to the early stage on the formation of LIPSS, in which the electron excitation via one or two photon absorption in a defect site cause local nanoablation at a laser fluence under the intrinsic ablation threshold, followed by the formation of a nanovoid, which act as a scatterer, and interference of scattered wave and laser pulses lead to HSFL formation.
| Original language | English |
|---|---|
| Pages (from-to) | 17990-17998 |
| Number of pages | 9 |
| Journal | Optics Express |
| Volume | 22 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - 2014 |
Fingerprint
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
Cite this
Contribution of defect on early stage of LIPSS formation. / Shimizu, Hisashi; Yada, Shuhei; Obara, Go; Terakawa, Mitsuhiro.
In: Optics Express, Vol. 22, No. 15, 2014, p. 17990-17998.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Contribution of defect on early stage of LIPSS formation
AU - Shimizu, Hisashi
AU - Yada, Shuhei
AU - Obara, Go
AU - Terakawa, Mitsuhiro
PY - 2014
Y1 - 2014
N2 - We investigated an early stage of laser-induced periodic surface structure (LIPSS) formation to elucidate the contribution of defects on the formation. 4H-SiC crystals were irradiated by multiple pulses of femtosecond laser with different laser spot sizes. We observed the decrease in formation thresholds of high-spatial-frequency LIPSS (HSFL) and lowspatial-frequency LIPSS (LSFL) with the increased irradiated laser spot size. For smaller laser spot size, HSFL was only formed at the periphery of LSFL formation area, whereas for larger spot size, HSFL was randomly distributed within the laser spot. Our results are coincident with the hypothesis that the existence of defects in crystal contributes to the early stage on the formation of LIPSS, in which the electron excitation via one or two photon absorption in a defect site cause local nanoablation at a laser fluence under the intrinsic ablation threshold, followed by the formation of a nanovoid, which act as a scatterer, and interference of scattered wave and laser pulses lead to HSFL formation.
AB - We investigated an early stage of laser-induced periodic surface structure (LIPSS) formation to elucidate the contribution of defects on the formation. 4H-SiC crystals were irradiated by multiple pulses of femtosecond laser with different laser spot sizes. We observed the decrease in formation thresholds of high-spatial-frequency LIPSS (HSFL) and lowspatial-frequency LIPSS (LSFL) with the increased irradiated laser spot size. For smaller laser spot size, HSFL was only formed at the periphery of LSFL formation area, whereas for larger spot size, HSFL was randomly distributed within the laser spot. Our results are coincident with the hypothesis that the existence of defects in crystal contributes to the early stage on the formation of LIPSS, in which the electron excitation via one or two photon absorption in a defect site cause local nanoablation at a laser fluence under the intrinsic ablation threshold, followed by the formation of a nanovoid, which act as a scatterer, and interference of scattered wave and laser pulses lead to HSFL formation.
UR - http://www.scopus.com/inward/record.url?scp=84905400502&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84905400502&partnerID=8YFLogxK
U2 - 10.1364/OE.22.017990
DO - 10.1364/OE.22.017990
M3 - Article
AN - SCOPUS:84905400502
VL - 22
SP - 17990
EP - 17998
JO - Optics Express
JF - Optics Express
SN - 1094-4087
IS - 15
ER -