【摘要】：對激光誘導(dǎo)等離子體參數(shù)進(jìn)行診斷有多種方法,其中采用發(fā)射光譜法對其診斷是一種重要的方法。文中采用Nd∶YAG固態(tài)激光器,輸出波長1 064nm紅外激光與鋁合金樣品相互作用,深入研究了鋁合金等離子體產(chǎn)生早期(1μs)譜線輪廓、譜線強(qiáng)度、線背比、譜線半峰寬及位移等隨時間演變規(guī)律。研究表明,激光與物質(zhì)相互作用早期,電子數(shù)密度非常大,電子與離子及原子之間的相互作用非常強(qiáng)烈,譜線的Stark展寬效應(yīng)非常明顯,導(dǎo)致多重譜線重疊在一起,隨時間演變,電子數(shù)密度及電子溫度的降低,多重譜線的半峰寬越來越窄且譜線輪廓對稱性越來越好。MgⅠ285.212 6nm譜線強(qiáng)度早期逐漸增強(qiáng),大約100ns左右譜線強(qiáng)度達(dá)到最大值,然后譜線強(qiáng)度呈逐漸減小的趨勢,這是由于等離子體產(chǎn)生早期,電子及離子占主導(dǎo)地位,故早期原子譜線強(qiáng)度較弱,隨時間演變,電子與離子之間的復(fù)合,原子數(shù)密度逐漸增加,故原子譜線逐漸增強(qiáng),達(dá)到最大值之后,由于等離子體激發(fā)溫度的降低,故譜線強(qiáng)度逐漸減弱。以NIST波長位置為參考,等離子體產(chǎn)生的早期譜線發(fā)生了紅移,連續(xù)背景強(qiáng)度隨時間演變呈冪函數(shù)形式急劇遞減,與之相反,譜線的連續(xù)背景強(qiáng)度與譜線強(qiáng)度相比,連續(xù)背景衰減的速度更為迅速,故導(dǎo)致譜線信背比隨時間演變呈增大趨勢,本研究對等離子體早期這些現(xiàn)象從理論角度進(jìn)行了深入探討。
[Abstract]:There are many methods to diagnose the parameters of laser-induced plasma, among which emission spectrometry is an important method. In this paper, Nd:YAG solid-state laser and 1 064nm infrared laser interacting with aluminum alloy samples are used to study the profile, intensity and back-to-back ratio of (1 渭 s) spectral lines in the early generation of aluminum alloy plasma. The half-peak width and displacement of spectral line evolve with time. The results show that in the early stage of laser-matter interaction, the electron number density is very large, the interaction between electrons and ions and atoms is very strong, and the Stark broadening effect of spectral lines is very obvious, which leads to the overlapping of multiple spectral lines and their evolution over time. With the decrease of electron number density and electron temperature, the half-peak width of multiple spectral lines becomes narrower and the symmetry of spectral lines becomes better and better. The intensity of Mg 鈪，

本文編號：2451200