Experimental Study On Cr: LiSAF Pumped By Pulse Red Laser

All-solid lasers attract keen interests in the field of laser techniques due to their high efficiency, compact structure, long lifetime, low cost and high quality laser beam. The appearances of tunable solid-state lasers inject fresh blood to solid-state lasers. They are widely applied in optical fiber communication, industrial production, biomedicine, laser weapon and so on. The research of tunable-laser crystal increases the practical value of solid-state laser source and make the ultra-fast optics get breakthrough progress, such as ultra-narrow femtosecond pulse, high peak power and so on. Among numerous tunable laser crystals, Cr3+:LiSrAlF6, short for Cr:LiSAF is one sort of new materials which can realize tunable output. It has some unique advantages, such as higher conversion efficiency, wider tuning range (750nm~1050nm), longer fluorescence life (67μs), large-peak launch section (5×10-20 cm-2), lower thermal lens effect, lower crystal scattering loss and so on. What's more, the phenomenon of concentration quenching will not happen when doping concentration is relatively high. These properties of the crystal, it gets scientists'consistent affirmation, and causes the concern of researchers. According to the study of nonlinear optical crystal and optical frequency conversion technology, it is found that the Cr:LiSAF tunable laser lies in blue-ray band, which is consistent with marine transport window. So it is the optimal source for underwater communication. Therefore, the potential applications of Cr:LiSAF laser are wildly distributed in scientific research, laser medicine, military communication and so on.This paper focus on all solid-state Cr:LiSAF lasers. After realizing high power solid-state red laser, the red laser generated from double-end-pumped by LD intracavity-frequency-doubling Nd:YV04/LB0 solid-state laser, the experimental research of Cr:LiSAF laser is discussed based on crystal characters. The paper includes basic theoretical analysis and detailed experimental study, and is mainly illustrated by the following five parts.1. Introduction. The development of solid laser and the advantages of tunable solid lasers are mainly concerned, among which, domestic and international progresses and development trend of Cr:LiSAF laser are introduced emphatically.2. The physical and optical properties of Cr:LiSAF laser are introduced in theory. It provides sufficient basis to laser research. We listed some important optical parameters of the crystal, and compared with other crystals to highlight the advantages of Cr: LiSAF.3. End-pumped intracavity-frequency-doubling Nd:YVO4/LBO solid-state laser is used in this experimental.Central wavelength of 671nm is obtained by analyzing rate equation, lumen harmonic theory, and resonator theory, whose peak power is 10.2mW. Comparing with others (laser diode, flash), this source has better laser beam and higher output power.4. In this experimental research,100ns output laser is achieved by pumping Cr:LiSAF crystal, whose central wavelength is 850nm with its tuning spectrum ranging from 820nm to 890nm, and repetition frequency is 11 KHz. The pump threshold power of the device is 24mW. The largest average output power of LiSAF laser could be 60mW, when pump power of red light is 521mW. A short-focal-length CCD detector and image-collection system are used to catch the output beam spot and then the data is observed and recorded in the computer. The shape and number of the spot can be changed by regulating crystal and output mirror. We have done some researches on the output spot, and analyzed the output optical characters under different conditions.5. The summary of work and achievements during researching period, and the prospect of subsequent research work.