摘要
详细研究了超短脉冲激光与生物组织相互作用的机理 ,建立了生物软组织中激光诱导光学击穿模型 ;结果表明 ,对于纳秒或亚纳秒脉冲激光 ,强吸收介质的热电子发射对电子雪崩电离过程有很大影响 ,等离子体光学击穿阈值随生物组织吸收的增加而降低 ;在激光脉宽为亚皮秒量级时 ,多光子电离成为光学击穿的主要机制 。
The mechanism of ultrashort laser interacting with biological tissues is investigated in detail and a model has been developed to calculate irradiance thresholds for laser induced optical breakdown in biological soft tissues.Calculation results has shown that for nanosecond or subnanosecond laser pulses,initial heating electrons in strongly absorbing media contributes significantly to avalanche ionization and optical breakdown threshold decreases with increasing tissue absorbance;for subpicosecond laser pulses,multiphoton ionization is the main mechanism for optical breakdown which is insensitive to linear absorption.When reached breakdown threshold,laser energy is deposited in thin layer with thickness of 1μm.For laser energy much higher than breakdown threshold,the effective light penetration depth is reduced.
出处
《激光杂志》
CAS
CSCD
北大核心
2004年第6期81-82,共2页
Laser Journal
