Study On Improvement Of Mid-Infrared Fluorescence Spectrometer System And Its Application

The mid-infrared(2～5 μm)laser is located in a relatively transparent atmosphere transmission window,covering many significant molecular characteristic spectral lines,for example,water molecules has a strong broad absorption peak in the about 3 μm.So the mid-infrared(2～5μm)laser has many potential applications in the medical,biological,military and other fields.In order to meet the test demand for the fluorescent characterization of mid-infrared laser materials,materials scientists have more requirements for testing functions and higher performance of the fluorescence spectrometer in mid-infrared band.In order to improve the testing performance of the mid-infrared fluorescence spectrometer,based on the original instrument framework,the method of instrument hardware replacement is adopted to improve the original instrument.Since the waveform generator is used to trigger a continuous semiconductor laser,the semiconductor laser can be used as a new excitation source,replacing the expensive optical parametric oscillation laser(OPO).First,the instrument principle,the hardware configuration,the measurement process and the data processing are introduced in detail,respectively.The system problems of the original instrument and the data acquisition problems of the oscilloscope have been pointed out.The original instrument is unable to measure the steady-state emission spectra of shorter lifetime samples in mid-infrared band.Secondly,the problems of oscilloscope data acquisition are analyzed in detail,and the easy solution is proposed that compensation probe is installed in the coaxial cable signal transmission line,so that capacitance compensation of coaxial cable between the detector and the oscilloscope is corrected by adjusting compensation probe.So the serious deformation is disappeared in the trailing part of the decay signal acquired by the oscilloscope.Meanwhile,we find out the reason and solution of sharp rising wrong peak of decay signal.Thirdly,the system problems of original instrument are analyzed in detail,and comparative analysis of various improvement methods have also been done.And the low-cost and easy to operate improvement method is adopted.Then the instrumental architecture and test preparation are also described in detail.The transient and quasi-steady-state emission testing process and parameter setting are introduced,and the process of time-resolved data slicing to get the emission spectrum is also introduced.Finally,rare-earth doped laser crystals and Cr2+ and Fe2+-doped semiconductors are measured as the experimental examples.It is proved that the improved instrument also can measure quasi-steady-state emission spectra and transient lifetime without OPO laser.Signal to noise ratio and spectral resolution are also improved.The experiment results show that the improved instrument not only has original test function and great improvement in emission spectral resolution and signal to noise ratio,but also has new important test functions that the quasi-steady-state emission spectrum can be measured for the short-lifetime fluorescent materials in mid-infrared band.Even if OPO laser is useless,the improved instrument can be used again to measure lifetime and emission spectrum of mid-infrared fluorescence.