An Efficient Bandstructure Algorithm for Determining Nonlinear Optical Coefficients in Semiconductor Heterostructures

11.21. Tliis piper deals nil11 ii iicw tylr of aiiio osc~lliii~o~~s tliiu arise during llie interaction ofn nv I'wr radiation wilh iiii nbrorbing liquid and do IIM coiiiied wtli ilie !raiisforiiiiiiioii of the iiicideiii laser hmii by tlie iiiaterial deslntctioii prcdizis Rcbably. tl~se oscilliitioiis uere discovercd wlieti ihe iirc (Gas Tuiigsleii Arc) aiigrneiiled laser anion on nietiils of the cw CO, INer radialioii iiiteiisity of Ss I0"L.q .. Win'' 13.41 W.IS iiivesligated Tlr iiii oftlie ppr is tlie experinmiitel invesliyatioii of llieautoaxillatioiis for a number olliqiiids aid iiiodeliiigof llie pmcess 111 our experiiiients w used 30 W cw CO2 laser. Tlie followiiig s~t of Ila absorbiiig liquids WIS used iii wr experiiiieiits. iiielted piralfiiie, itiiiieral oil. wuiini oil, glycerine. pnladffane. diiiietliylfoflih~iiit. wter. eillaiiol. acetone. pentane A keyhole w formed iiear tlie liquid surface some tina after switching on llie I.wr ndiatioii A oericdical axillations of the kevliole deo(h a"I after llie boiliiur win1 of tlm hid was reached Under tlim . ... conditioiis a miiveCtive flows uere loriiied in the liquid t The niechaiiisiii of tlie plieiionienoii may be described as follows When the boiling point of the liquid wds reached tlie remive moil pressure iinpulse pislied dowm the keyhole bottom to tlie region of lowr radiatiori intensity. Tlie heated liquid layers were pushed down deep into the liquid aid a cold liquid layers replaced Iliein The liquid teiriperature at the keyhole boctoin w reduced and tlie recoil pressure was also reduced. Tlieii since hydrostatic pressure aid surface teiision teiids to return the liquid surface to an equilibrium pition the keyhole bononi was iiiowd iipwrds along the laser hii. The liquid moved to the region of larger radiation iiiieiisity and was heated again. The qualitative iiiodel was developed IO interpret the expeninental resulls. The basic regularities of the observed phenomenon wre inherent both to tlie nietal melt [3] and to tlie investigated atsorbing liquids. Therefore the modeling was carried out as for example for arc (GTA) augriieiited Imr efen on low &n -. ie pndical mi1 pressure of !lie vapor