摘要
在飞秒激光与固体靶相互作用中,利用OMA光学多道分析谱仪,在靶前表面激光镜反方向测量了激光的二次谐波(2ω0)光谱和三次谐波(3ω0)光谱,观测到了红移的2ω0光谱和3ω0光谱的伴线结构。在激光功率密度为～1018W.cm-2的条件下,通过2ω0和3ω0谐波光谱的伴线结构,回推出激光与等离子体相互作用中产生的自生磁场均小于1MGs。随着激光功率密度的增大,谐波谱红移峰向长波方向移动,光谱同时发生展宽。分析认为,等离子体临界面的迅速膨胀是导致二次谐波和三次谐波红移的主要原因。随着预脉冲功率密度的增大,临界面膨胀速度增大,导致了谐波光谱峰更大的红移。自生磁场的测量为诊断临界面的运动方向和速度提供了新的依据。
The satellites structures of doubling harmonic spectrum and tripling harmonic spectrum were measured at the reflection direction of laser wave from the front side of targets, employing OMA optical multi-channel spectrometer during the interactions of femtoseeond laser with solid targets. The satellites structures of red-shift harmonic spectrum of 2ω0 and 3ω0 were observed. Under the intensity of ～10^18 W·cm^-2 , the result of measurement indicates that the spontaneous magnetic field was all less than 1 MGs level by analyzing the satellites structures of doubling harmonic spectrum and tripling harmonic spectrum during the laser-plasma interaction. With increasing the intensity of the laser pulse, the peak of the red-shift moves further to the long wavelength side causing the broadening of the spectrum. The measurements of the spontaneous magnetic field provide a basis of diagnosing the movement of the critical surface in the laser-plasma interaction process.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2007年第10期1917-1920,共4页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(10535030)
四川省青年科技基金项目(06ZQ026-053)
成都医学院科研基金项目(05Z2005-001)资助
关键词
飞秒激光
谐波光谱
伴线结构
自生磁场
红移
Femtosecond laser
Harmonic spectrum
Satellites structures
Spontaneous magnetic field
Red-shift
