Finite-element simulation of photoinduced strain dynamics in silicon thin plates

被引:5
|
作者
Nakamura, A. [1 ]
Shimojima, T. [1 ]
Ishizaka, K. [1 ,2 ,3 ]
机构
[1] RIKEN Ctr Emergent Matter Sci, Wako, Saitama 3510198, Japan
[2] Univ Tokyo, Quantum Phase Elect Ctr, Bunkyo Ku, Tokyo 1138656, Japan
[3] Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan
来源
STRUCTURAL DYNAMICS-US | 2021年 / 8卷 / 02期
关键词
D O I
10.1063/4.0000059
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In this paper, we investigate the femtosecond-optical-pulse-induced strain dynamics in relatively thin (100 nm) and thick (10 000 nm) silicon plates based on finite-element simulations. In the thin sample, almost spatially homogeneous excitation by the optical pulse predominantly generates a standing wave of the lowest-order acoustic resonance mode along the out-of-plane direction. At the same time, laterally propagating plate waves are emitted at the sample edge through the open edge deformation. Fourier transformation analysis reveals that the plate waves in the thin sample are mainly composed of two symmetric Lamb waves, reflecting the spatially uniform photoexcitation. In the thick sample, on the other hand, only the near surface region is photo-excited and thus a strain pulse that propagates along the out-of-plane direction is generated, accompanying the laterally propagating pulse-like strain dynamics through the edge deformation. These lateral strain pulses consist of multiple Lamb waves, including asymmetric and higher-order symmetric modes. Our simulations quantitatively demonstrate the out-of-plane and in-plane photoinduced strain dynamics in realistic silicon plates, ranging from the plate wave form to pulse trains, depending on material parameters such as sample thickness, optical penetration depth, and sound velocity.
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页数:8
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