Basic Research on Optical Induced Actuator

• Project/Area Number: 03452086
• Research Category: Grant-in-Aid for General Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: 物理計測・光学
• Research Institution: Gunma Univ.
• Principal Investigator: YOSHINO Toshihiko Gunma Univ. Faculty of Eng. Professor, 工学部, 教授 (90013169)
• Co-Investigator(Kenkyū-buntansha): TAKAHASHI Yoshitaka Gunma Univ. Faculty of Eng. Res. Assoc., 工学部, 助手 (30216767)
• Project Period (FY): 1991 – 1992
• Project Status: Completed (Fiscal Year 1992)
• Budget Amount: ¥4,700,000 (Direct Cost: ¥4,700,000); Fiscal Year 1992: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 1991: ¥3,500,000 (Direct Cost: ¥3,500,000)
• Keywords: Photothermal Effect / Actuator / Surface Acoustic Wave / アクチュエ-タ / レイリ-波

Research Abstract

Basic research on optical induced actuator was carried out. Irradiating laser beam generates lattice vibration on a substrate surface and causes to surface acoustic waves. The object on the substrate stage receives moving force without contact nor tracks.
1. Measurement of characteristics of photothermal displacement. With Q-switched Nd^<3+>:YAG-SHG laser irradiation on a solid surface, some characteristics (power dependence, difference by the methods of excitation, etc.) of induced photothermal displacement was measured for several metal samples. The Michelson interferometer was used to measure it. Some models were considered and theoretically investigated to clarify the mechanism of induced photothermal displacement.
2. Measurement of optical damage threshold. For these samples the threshold of the optical power was measured to damage the surface. Taking the physical parameters of each samples into consideration (ex. melting point, specific heat, expansion coefficient, thermal conductivity, etc.), the optical damage threshold was numerically estimated and compared to the measured value.
3. Experiment of laser-induced motion. Using the stage made by horizontally supported aluminum foil as the substrate, the experiment was performed to move a piece of cover glass and a micro plastic ball on it by the optical induced displacement which was generated by Q-switched Nd^<3+>:YAG-SHG laser irradiation. But no evidence was observed of those motion.
4. Excitation of photothermal displacement by optical scanning. Photothermal displacement was observed by switching the exciting light from Ar^+ laser. Using a polygon mirror to scan the laser light, the synchronized photothermal displacement was observed and the scanning frequency and wavelength dependence was measured.