铬原子束激光感生荧光强度的理论和实验

Theoretic and Experimental Study on Intensity of Laser Induced Fluorescence Derived from Cr Atomic Beam

采用铬原子束激光感生荧光激光稳频技术解决铬原子光刻实验中激光频率随时间漂移的问题.从理论和实验两个方面对铬原子束激光感生荧光强度随激光功率和坩埚温度的变化情况进行了研究.结果显示,在坩埚温度一定的情况下,由于铬原子的饱和效应,当激光功率增大到6 mW左右时,荧光斑点的中心强度会达到饱和然后随激光功率的增加变化不大.另外,随着激光功率的增加,荧光斑点轮廓曲线的半高宽在变大的同时,对比度减小.在激光功率一定的情况下,由于铬原子喷射的个数与坩埚温度成正比,荧光斑点的中心强度随坩埚温度的增加而增加,并且不出现饱和效应;随着坩埚温度的升高,荧光斑点轮廓曲线的半高宽基本不变,而对比度增大.这些变化趋势和理论结果符合地很好.

Laser frequency stabilization derived from Cr atomic beam laser induced fluorescence is a good way to solve excursion of laser frequency in Cr atom lithography. Calculation and experiments are conducted to reveal the effects of laser power and crucible temperature on the induced fluorescence intensity . With fixed crucible temperature, the central intensity of fluorescence doesn＇t change very much after the laser power reaches 6mW due to the Cr saturation absorption. In addition, the higher power the laser has, the larger full width at half maximum （FWHM）, and the lower contrast the fluorescence will have. With fixed laser power, the higher temperature the crucible is at, the higher central intensity fluorescence will have due to the fact that the higher temperature of crucible can make more atoms, and the sharper contrast it will have, but the FWHM doesn＇t change much with crucible temperature. The experiment result agrees with calculation well.