@misc{oai:ir.soken.ac.jp:00000350,
 author = {PHAM, MINH HONG and パム, ミン ハウ and PHAM, MINH HONG},
 month = {2016-02-17, 2016-02-17},
 note = {Recently，various new fluoride crystals have been developed as host for solid-state tunable UV lasers. Cerium（Ce）doped laser materials have been developed for use in the direct and efficient generation of tunable ultraviolet（UV）laser using a UV pump source．These have emerged as convenient and compact laser sources based on the electronically dipole-allowed interconfigurational 5d-4f transitions of Ce<sup>3＋</sup>ions in wide band-gap fluoride crystals. They are especially attractive for ultrashort-pulse generation and amplifications in the UV region．Among these crystal Ce<sup>3+</sup>;LiCaAIF<small>6</small>（Ce：LiCAF）which was first reported  by M.A.Dubinskii et al in 1993，is the first known tunable UV laser directly pumped by the fourth harmonic of standard Nd：YAG laser. It proved to have sustained high output due to the absence of solarization effects therefore leading to efficient and sustained high power laser emission. This crystal is typically grown by the Bridgman and Czochralski（CZ）methods. Part of the difficulty in developing new materials is the high cost and difficulty in producing large crystals by standard crystal growth methods. To economically and efficiently grown a large crystal with laser quality，the micro-pulling down（μPD）method modified for fluoride crystal growth is advantageous. Owing to a fast growth speed，a high quality crystal can be grown at  a shorter time and at a lower cost compared with other melt growth schemes. Moreover, μ-PD method has the capability to control the shape of the grown crystal to produce fiber; rod; tube, and so on .In this thesis,   successful growth of a laser-quality Ce:LiCAF crystal using the micro-pulling down method is described. To improve the Ce:LicAF laser quality we also described the numerical simulation for optical properties of Ce:LiCAF. This is the first Ce:LiCAF crystal to be grown by the μ-PD method, thus its basic optical  properties have to be investigated. Primarily, given specified experimental parameters, the goal was to determine the important optical parameters of the Ce:LiCAF sample in order to design the appropriate  experimental conditions. The properties that were investigated using numerical methods were radius, absorption coefficient, and absorption profile for specified given values of optical pump beam diameter, pump energy and an assumed refractive index for Ce:LiCAF. One way of possibly increasing the laser output power for the Ce:LiCAF laser oscillator is to design a multiple side pumping scheme. In the experiment, the prismatic cell was applied for the first time in this work to a solid state laser system. It can offer an improved laser output beam quality due to more uniform electric field distribution in the crystal. It could also reduce the risk of damage in the crystal. Moreover multi-pass pumping will yield high power.   This pumping geometry is similar in principle to a prismatic cell that was previously used in dye laser and was applied for the first time in this work to a solid-state laser system. This will be especially important in designing a high energy optically pump Ce:LiCAF laser. The quality of the Ce:LiCAF crystal as a laser  material was then experimentally evaluated. A slope efficiency of 10% for the one, two-side, and multiple side pumping configurations were achieved. The experiment also showed that the slope efficiency improved from l0% to 23% when the sample's output windows were cut at Brewster angle. It should be noted that the samples that were studied in this work did not have polished sides, thus, explaining the relatively low slope efficiency values. Maximum output pulse energy of 1 mJ at 290 nm is achieved with an absorbed pump energy of 6 mJ with a slope efficiency of 23%. The lasing threshold is 2.5 mJ, which corresponds to a threshold fluence of 10 mJ/cm<sup>2</sup>. The emission at 290 nm has a pulse width of approximately 4 ns. This is the first demonstration of lasing in the ultraviolet region from a μ-PD method grown fluoride crystal. The flexibility and lower cost of this crystal growth scheme will drastically reduce the cost of crystal growth.  This improvement will strongly enhance the applications of Ce:LiCAF laser itself., 総研大甲第1187号},
 title = {Ultraviolet Laser Emission form a Micro-Pulling Down Method Grown Ce3+:LiCaAlF6},
 year = {}
}