The main results are as follows : 1 . the propagation of an ultrashort intense pulse laser beam in low - density plasmas is investigated analytically . relativitistic pondermotive force and space - charge effects are included , and an equation describing the evolution of the laser spot size is derived 考慮有質(zhì)動(dòng)力與電荷分離場(chǎng)的平衡,推出了超短超強(qiáng)脈沖激光在低密度等離子體中的折射率、電子密度和電荷分離場(chǎng)的表達(dá)式以及激光束斑的演化方程。
Ultrashort intense laser pulse propagation in low - density plasmas and air xiao yuan , doctor of philosophy , 2002 dissertation advised by : lu baida , professor of physics the study of ultrashort intense pulse laser beams in low - density plasmas and air is relevant to a wide range modern application 超短超強(qiáng)脈沖激光在低密度等離子體和空氣中的非線性傳輸是當(dāng)今強(qiáng)激光與物質(zhì)相互作用研究的一個(gè)重要課題。本論文闡述了超短超強(qiáng)激光在低密度等離子體和空氣中的長(zhǎng)距離自聚焦和自導(dǎo)引效應(yīng)。
When passed through the beam - splitter , a pulsed laser beam was split into 3 beams with an interpulse delay of 13 ns . these 3 separated laser pulses reach the m - z interferometer at different time and each laser pulse gave a snapshot of the implosion state . thus three different - time interferograms can be obtained in one shot of z - pinch 激光器發(fā)出的光束經(jīng)過分光系統(tǒng)被分成時(shí)間間隔13ns的三束光,它們于不同的時(shí)刻先后到達(dá)m - z干涉儀,每一束激光脈沖可以記錄下等離子的一個(gè)狀態(tài),從而可以得到三幅不同時(shí)刻的干涉圖。
In the master thesis , the fatigue characteristics of the ferroelectric films under thermal load and electrical load were investigated . the thermal load was induced by a pulse laser beam of nd : yag and the electrical load was made by rt6000s ferroelectric tester t o act on the films respectively . the effect of thermal or electric loads on the films properties was discussed 本文對(duì)鐵電薄膜在循環(huán)的熱載荷和電載荷作用下的疲勞特性進(jìn)行了研究,分別用nd : yag脈沖激光器模擬熱載荷、用rt6000s鐵電測(cè)試儀模擬電載荷作用于鐵電薄膜,根據(jù)實(shí)驗(yàn)結(jié)果探討了這兩種載荷對(duì)鐵電薄膜性能的影響。