Nanosecond pulsed laser irradiation of sapphire for developing microstructures with deep V-shaped grooves

Nozomi Takayama, Shouhei Asaka, Jiwang Yan

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A nanosecond pulsed Nd:YAG laser was used to irradiate a sapphire substrate to produce 3-dimensional microstructures with sharp V-shaped grooves. In initial experiments, where single grooves were machined, a maximum taper angle of ~79° was obtained. At constant laser parameters, the taper angle remained constant. As the taper angle increases from a flat surface, the irradiated area increases while incident fluence decreases; once the incident fluence approaches the ablation threshold, the taper angle becomes constant. The taper angle could be controlled by the laser fluence, scanning speed and incident angle of the laser beam. Using these results, a kind of surface microstructure, comprised of micropyramids with steep walls, was successfully machined for optical measurement applications. The surface roughness, transmittance and crystallinity of the microstructure surface could be controlled by the laser scanning speed. By applying the taper formation mechanism proposed in this study, the micromachining of sharp microstructures with steep walls on various hard brittle materials becomes possible.

Original languageEnglish
JournalPrecision Engineering
DOIs
Publication statusAccepted/In press - 2018 Jan 1

Fingerprint

Laser beam effects
Pulsed lasers
Sapphire
Microstructure
Lasers
Scanning
Micromachining
Brittleness
Ablation
Laser beams
Surface roughness
Substrates
Experiments

Keywords

  • Groove formation
  • Hard brittle material
  • Laser processing
  • Microstructure
  • Optical element micromachining
  • Sapphire
  • Taper formation

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Nanosecond pulsed laser irradiation of sapphire for developing microstructures with deep V-shaped grooves. / Takayama, Nozomi; Asaka, Shouhei; Yan, Jiwang.

In: Precision Engineering, 01.01.2018.

Research output: Contribution to journalArticle

@article{4b9a6a4f59394ef59129416279075833,
title = "Nanosecond pulsed laser irradiation of sapphire for developing microstructures with deep V-shaped grooves",
abstract = "A nanosecond pulsed Nd:YAG laser was used to irradiate a sapphire substrate to produce 3-dimensional microstructures with sharp V-shaped grooves. In initial experiments, where single grooves were machined, a maximum taper angle of ~79° was obtained. At constant laser parameters, the taper angle remained constant. As the taper angle increases from a flat surface, the irradiated area increases while incident fluence decreases; once the incident fluence approaches the ablation threshold, the taper angle becomes constant. The taper angle could be controlled by the laser fluence, scanning speed and incident angle of the laser beam. Using these results, a kind of surface microstructure, comprised of micropyramids with steep walls, was successfully machined for optical measurement applications. The surface roughness, transmittance and crystallinity of the microstructure surface could be controlled by the laser scanning speed. By applying the taper formation mechanism proposed in this study, the micromachining of sharp microstructures with steep walls on various hard brittle materials becomes possible.",
keywords = "Groove formation, Hard brittle material, Laser processing, Microstructure, Optical element micromachining, Sapphire, Taper formation",
author = "Nozomi Takayama and Shouhei Asaka and Jiwang Yan",
year = "2018",
month = "1",
day = "1",
doi = "10.1016/j.precisioneng.2018.02.008",
language = "English",
journal = "Precision Engineering",
issn = "0141-6359",
publisher = "Elsevier Inc.",

}

TY - JOUR

T1 - Nanosecond pulsed laser irradiation of sapphire for developing microstructures with deep V-shaped grooves

AU - Takayama, Nozomi

AU - Asaka, Shouhei

AU - Yan, Jiwang

PY - 2018/1/1

Y1 - 2018/1/1

N2 - A nanosecond pulsed Nd:YAG laser was used to irradiate a sapphire substrate to produce 3-dimensional microstructures with sharp V-shaped grooves. In initial experiments, where single grooves were machined, a maximum taper angle of ~79° was obtained. At constant laser parameters, the taper angle remained constant. As the taper angle increases from a flat surface, the irradiated area increases while incident fluence decreases; once the incident fluence approaches the ablation threshold, the taper angle becomes constant. The taper angle could be controlled by the laser fluence, scanning speed and incident angle of the laser beam. Using these results, a kind of surface microstructure, comprised of micropyramids with steep walls, was successfully machined for optical measurement applications. The surface roughness, transmittance and crystallinity of the microstructure surface could be controlled by the laser scanning speed. By applying the taper formation mechanism proposed in this study, the micromachining of sharp microstructures with steep walls on various hard brittle materials becomes possible.

AB - A nanosecond pulsed Nd:YAG laser was used to irradiate a sapphire substrate to produce 3-dimensional microstructures with sharp V-shaped grooves. In initial experiments, where single grooves were machined, a maximum taper angle of ~79° was obtained. At constant laser parameters, the taper angle remained constant. As the taper angle increases from a flat surface, the irradiated area increases while incident fluence decreases; once the incident fluence approaches the ablation threshold, the taper angle becomes constant. The taper angle could be controlled by the laser fluence, scanning speed and incident angle of the laser beam. Using these results, a kind of surface microstructure, comprised of micropyramids with steep walls, was successfully machined for optical measurement applications. The surface roughness, transmittance and crystallinity of the microstructure surface could be controlled by the laser scanning speed. By applying the taper formation mechanism proposed in this study, the micromachining of sharp microstructures with steep walls on various hard brittle materials becomes possible.

KW - Groove formation

KW - Hard brittle material

KW - Laser processing

KW - Microstructure

KW - Optical element micromachining

KW - Sapphire

KW - Taper formation

UR - http://www.scopus.com/inward/record.url?scp=85042351002&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85042351002&partnerID=8YFLogxK

U2 - 10.1016/j.precisioneng.2018.02.008

DO - 10.1016/j.precisioneng.2018.02.008

M3 - Article

AN - SCOPUS:85042351002

JO - Precision Engineering

JF - Precision Engineering

SN - 0141-6359

ER -