Growth And SRS Properties Investigation Of Tetraphenylphosphonium Bromide Bulky Crystal And Single-crystalline Fiber

Laser is regarded as one of the greatest invention because it has promoted the development of science and the progress of society since it was invented.On the aspect of the basic science,people have deeper insights into the fundamental physics and the essence of many physical phenomenon.And on the aspect of the useful technology,many technologies based on laser have improved human's life such as laser medicine,optical fiber communication,laser processing,laser display,laser survey,laser sense and so on.The methods of generating laser include direct pumping and non-linear optics(NLO)conversion in which the NLO conversion is an important method to generate laser with new wavelength as the scarcity of the laser materials that can create laser directly by pumping.The NLO conversion is in the range of highlight optics and has been developing with the laser science and technology.When laser interacts with material,the inner electric field of material will be polarized by the electric field of light,and the polarized inner electric will retroact with the electric field of light which can lead to the changes of light frequency.Crystalline materials have been the prior research target because of their advantages including high efficiency of non-linear conversion,good optical transmission,stable mechanical behavior,which are used in all solid devices.Stimulated Raman scattering(SRS),as an important third-order nonlinear effect,has been wide used in Raman laser devices.Raman crystals are important NLO materials,in which traditional Raman crystals are inorganic crystals with good thermal and mechanical behavior based on the mature technology of crystal growth and processing.Most of the Raman shift of traditional inorganic Raman crystals is shorter than 1000cm-1,and high pumping energy is needed to arouse SRS.In recent years,with the development of related areas,the miniaturization,lower dimension and lower energy of laser materials and laser devices become new need.Concerning Raman laser materials,organic crystalline materials can provide much larger Raman shift than 3000cm-1,which are easy to obtain low dimension structures.What's more,organic crystalline materials have a great variety and lower cost.So,organic crystalline materials have attracted attention to potential Raman laser materials.The main work of this thesis is exploring new organic Raman laser crystalline material.Concretely,the work is about the crystal growth and basic physical properties study of bulk single crystal of tetraphenylphosphonium bromide dehydrate(TPPB · 2H2O);the preparation,waveguide properties and SRS properties research of TPPB · 2H2O single-crystalline optical fibers and the discussions of the growth kinetics of single-crystalline fiber.The main work of this thesis can be divided in to two parts depends on the dimension and scale of material:The first part includes chapter 2 and chapter 3.In this part,the bulk single crystal with several centimeters size has been grown by traditional slow-cooling method,the methods and questions of the organic crystal growth have been summarized.The crystal structure and basic physical properties of TPPB · 2H2O has been confirmed and studied.We also have confirmed the crystal direction of TPPB ·2H2O,processed the crystal and tried SRS laser experiment.The second part includes chapter 4,chapter 5 and chapter 6.In this part,we have prepared TPPB ·2H2O single-crystalline optical fibers with high quality and large aspect ratio by self-assembly method in solution.The lengths of the TPPB · 2HO single-crystalline optical fibers reach several millimeters and the width can keep less than several tens of microns.We have achieved the waveguide properties and SRS properties by self-built optical measurement system,and got multicolor SRS laser by pumping with low power 532 nm CW laser and analyzed the quantitative relationship between the SRS light intensity and the pump light power.Finally,we have come up with qualitative explanation to the mechanization of one-dimensional growth of TPPB · H2O single-crystalline fibers based on the experimental phenomena,crystal structure and PBC theory.The main innovation points of this thesis can be summarized as follows:1.Centimeter scale bulk crystal of TPPB · 2H2O has been grown with top-seeded solution growth method for the first time.The crystal is transparent with regular shape and high quality.2.The crystal structure of TPPB · 2H2O has been ensured to replenish the old crystal structure information reported in 1975.The basic physical properties such as hardness,thermal properties and optical properties have been investigated for the first time.3.Millimeter scale single-crystalline fibers of TPPB · 2H2O has been prepared successfully by solution droplet self-assembly method.4.Multicolor SRS lasers with wavenumbers at three different location have been achieved and the reason has been discussed by comparing with bulk crystal.5.The growth kinetics of TPPB·2H2O single-crystalline fiber was discussed by observing the growth processes in situ observations.