,A sapphire fibre thermal probe based on fast Fourier transform and phase-lock loop

• 作 者: Wang Yu-Tian Wang Dong-Sheng Ge Wen-Qian Cui Li-Chao
• 机 构: Department of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China
• 出 处: 中国物理（英文版）
• 发表日期: 2006年5期
• 关键词: fluorescence thermometer fast Fourier transform phase-lock loop sapphire optical

A sapphire fibre thermal probe with Cra+ ion-doped end is developed by using the laser heated pedestal growth method. The fluorescence thermal probe offers advantages of compact structure, high performance and ability to withstand high temperature in a detection range from room temperature to 450℃. Based on the fast Fourier transform(FFT), the fluorescence lifetime is obtained from the tangent function of phase angle of the non-zeroth terms in the FFT result. This method has advantages such as quick calculation, high accuracy and immunity to the background noise. This FFT method is compared with other traditional fitting methods, indicating that the standard deviation of the FFT method is about half of that of the Prony method and about 1/6 of that of the log-fit method. And the FFT method is immune to the background noise involved in a signal. So, the FFT method is an excellent way of processing signals. In addition, a phase-lock amplifier can effectively suppress the noise.