The Application Of Temperature Measuring By Fluorescence Lifetime Method In The Solid Laser Cooling

In this paper we introduce the principle of solid laser cooling and its development history first.We found that the development trend of solid laser cooling-improving the efficiency of solid laser cooling to get a lower refrigeration temperature.Microspherical cavity has extremely high quality factor,can enhance the efficiency of the solid laser cooling.So it becomes a research hotspot.But we found that all the existing temperature measuring technology can't apply to tiny volume microspherical cavity.In order to solve the temperature measuring problem in microspherical cavity solid laser cooling experiments,we proposed a new kind of temperature measurement scheme by fluorescence lifetime method.In order to get the relationship between fluorescence lifetime and temperature,we studied the relationship between the particle number distribution of the excited levels and temperature using the typical level structure of rare earth materials and the Boltzmann distribution.We found that with the increase of temperature,fluorescence lifetime decreased.According to the definition of fluorescence lifetime,we designed an algorithm to get fluorescence lifetime from fluorescence decay curve,we insert DC interference,periodic interference,sudden interference etc,in the fluorescence decay curve to revise the algorithm.Finally,we designed a"fluorescence lifetime automatic detection system",it can detect the relationship between the fluorescent lifetime and temperature automatically.In the experiment,we study the relationship between under conversion transformation fluorescence lifetime and temperature first.We proposed "rapid temperature measuring probe"scheme to applied under transformation fluorescence lifetime temperature measuring method in traditional solid laser refrigeration.Compared with the traditional temperature measurement scheme,it has advantages likes simple structure,fast and high precision,minimal interference of refrigeration system.Secondly,we proposed a scheme to measurement the temperature in micro-cavity solid laser cooling experiment based on the relationship between up conversion fluorescence lifetime and temperature.The study includes the mechanism of up conversion transformation fluorescent,material preparation of under conversion transformation fluorescent,fluorescence lifetime detection scheme,the calibration of under conversion transformation fluorescence lifetime relationship with temperature,etc.In this scheme,we use the solid laser cooling material itself as the temperature measurement material,so when accurate measuring the temperature it will not to introducing interference to cooling system at the same time.A scheme to applied up conversion transformation fluorescent temperature measuring method to traditional solid laser cooling experimental is given too.For microspherical cavity,we proposed"double optical fiber coupling temperature measurement scheme" and "Y type optical fiber coupling temperature measurement scheme".At the end of this article,we proposed a new method to measuring temperature in microspherical cavity solid laser cooling experiment by the relationship between the lifetime of anti-stokes fluorescence(the fluorescence luminesce by solid laser cooling process)and temperature.However,due to the limitation of experiment equipment,we unable to obtain pure solid laser cooling material,so this scheme never validated by experiment yet.