CAJ | 학술논문

飞秒激光泵浦瞬态热反射技术是研究金属薄膜超快动力学的有效手段，这种技术具有两大突出特点：首先，可以揭示飞秒激光激发的微观电、声子的传输过程是一个非平衡热输运过程。其次，反射率瞬态变化实验中电子运动的超短时间分辨可以用来研究热过程中电子的非平衡相互作用情况。利用磁控溅射真空镀膜技术，在玻璃衬底和硅衬底上蒸镀了不同厚度的Co单层膜，Cr ，Co双层膜以及Ag ，Co双层膜。利用飞秒激光瞬态反射技术研究了Co膜及其双层膜的瞬态反射率响应。结果表明，在同一厚度的Co膜样品上，施加不同的泵浦光功率时，Co膜内电子的加热时间与泵浦光功率的大小无关，均为0.1344 ps。而对于不同厚度的Co膜，电子的热化时间与薄膜厚度直接相关。此外，发现与以往研究结果不同的是，在泵浦光功率足够大时，玻璃衬底上的Co膜在飞秒激光脉冲泵浦下会出现两次或三次瞬态反射率下降现象，Co膜厚度决定了Co膜内瞬态反射率突变的次数，即Co膜内电子的超快动力学变化次数。
비초격광빙포순태열반사기술시연구금속박막초쾌동역학적유효수단，저충기술구유량대돌출특점：수선，가이게시비초격광격발적미관전、성자적전수과정시일개비평형열수운과정。기차，반사솔순태변화실험중전자운동적초단시간분변가이용래연구열과정중전자적비평형상호작용정황。이용자공천사진공도막기술，재파리츤저화규츤저상증도료불동후도적Co단층막，Cr ，Co쌍층막이급Ag ，Co쌍층막。이용비초격광순태반사기술연구료Co막급기쌍층막적순태반사솔향응。결과표명，재동일후도적Co막양품상，시가불동적빙포광공솔시，Co막내전자적가열시간여빙포광공솔적대소무관，균위0.1344 ps。이대우불동후도적Co막，전자적열화시간여박막후도직접상관。차외，발현여이왕연구결과불동적시，재빙포광공솔족구대시，파리츤저상적Co막재비초격광맥충빙포하회출현량차혹삼차순태반사솔하강현상，Co막후도결정료Co막내순태반사솔돌변적차수，즉Co막내전자적초쾌동역학변화차수。
In the present paper ,cobalt films ,chromium and cobalt double layer films ,and silver and cobalt double layer films were deposited by magnetron sputtering technique .The transient reflectivity response in cobalt thin films and their double layer films was studied by using femtosecond laser pump-probe transient reflection experimental technology .The result shows that , under the condition of the cobalt films of the same thickness ,when the pump power increases ,the heating time of the electrons in cobalt thin films is independent of the pump power ,and is 0.134 4 ps .And for the cobalt films of different thickness ,the e-lectron thermalization time is directly related to the film thickness .In addition ,when the laser pulse power is high enough ,two or three transient reflectivity decline signals on glass substrate films are found which is different with previous researches ,when the cobalt films were thin ,there are three times of transient reflectivity abruptly decline signals ,and when the cobalt films were thick ,there are two times of transient reflectivity abruptly decline signals ,so the thickness of the cobalt films determines the times of the changes of the ultrafast dynamics in cobalt films .