Fabrication of doped ZnO spherical crystals by optical vortex laser processing

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H03888
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Optical engineering, Photon science
• Research Institution: Kyushu University
• Principal Investigator: NAKAMURA DAISUKE 九州大学, システム情報科学研究院, 准教授 (40444864)
• Research Collaborator: OKADA Tatsuo ; IKENOUE Hiroshi ; OMATSU Takashige ; MAMIDANNA SRI RAMACHANDRA Ramachandra Rao
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 微小共振器 / ウィスパリングギャラリーモード / 光渦レーザープロセス

Outline of Final Research Achievements

We proposed optical vortex laser processing to fabricate semiconductor microspherical crystals and to control their size and ejection direction. Size- and position-controlled ZnO microspherical crystals were successfully fabricated by optical vortex laser ablation in air, and they showed ultraviolet (UV) whispering gallery mode (WGM) lasing under pulse laser excitation. In order to expand the functionalities of the sphere-based optical micro-cavity, alloy and doped microspherical crystals such as ZnMgO and Ho-doped ZnO were fabricated. The WGM lasing wavelength of ZnMgO microspherical crystal was blue-shifted from 400 nm to 355 nm with increasing concentration of Mg. In addition, we demonstrated that UV and visible WGM from single Ho-doped ZnO microspherical crystal with different laser excitation of 355 nm pulse laser and 488 nm continuous laser.

Free Research Field

レーザー工学

Academic Significance and Societal Importance of the Research Achievements

近年，光渦レーザーを材料加工に応用する研究が注目されてきている中で，本研究ではマイクロサイズの半導体結晶球を大気中にて合成し，そのサイズおよび飛翔方向を制御可能であることを実験的に明らかにした点において学術的意義がある．合成した不純物ドープZnO結晶球は，紫外から可視領域においてWGMスペクトルが得られるため，微小レーザーや高感度センサ応用が期待できる．また，ZnOは生体適合性の高い材料でもあるため，バイオセンサ等へも応用が期待できる．