固態雷射由於其具有效率高、壽命長、結構緊湊、高品質輸出模態等特點，是目前雷射研究中最為活躍的領域之一。在雷射的諸多應用中，尤以光學上的非線性轉換，需要一個高尖峰功率的雷射來作為泵浦光源。現今已存在各式高能量電射光源，可滿足需求，卻存在花費過高，輸出頻率低造成量測不易等缺點。我們的目標是建立一個花費較為經濟，輸出效率亦高的主動式Q開關雷射。本論文中所製作的二極體激發式高效率針型摻釹釔鋁石榴石雷射，乃藉由將增益介質的截面積由3x3平方厘米縮小至1x1平方厘米,使泵浦光源和腔內共振雷射在空間模態上的重疊效率提升，同時縮短了晶體內部熱傳導的路徑，來達到更高能量且持續穩定輸出的效果。經由量測計算，在連續輸出的模式下, 當輸出耦合透鏡的反射率為85%時,雷射輸出之斜率效率為31.78%，其輸出模態的Ｍ2值為1.69，等效的熱透鏡焦距為25公分。此雷射中插入一個主動式Q開關，利用聲光調變晶體控制雷射共振腔的輸出重覆頻率，高重覆頻率可以降低雜訊水平強度，以提升量測準確性，並且降低量測上的困難度。實驗結果顯示，當輸出耦合透鏡的反射率為70%時，有最好的脈衝輸出，其脈衝強度為559微焦耳，脈衝寬度為8.7奈秒。此外，經由自行設計的水冷系統，有效的傳導雷射晶體以及聲光調變晶體內部產生的熱，以維持輸出的穩定性。

Solid-state lasers is one of the most active region of laser research, because of its characteristics such as high efficiency, long life, compact size, and high quality mode. For many applications, especially the nonlinear frequency conversion, it needs a high peak power laser source. Although there have been various laser source capable of producing sufficient laser energy, the cost and the size of the laser system is unfriendly to users. Our goal is to buildup a more economic and high efficiency active Q-switched laser. In this thesis, we approached the higher and steadier power by reducing the cross-section area from 3x3 mm2 to 1x1 mm2. When the dimension of the gain medium is reduced, the overlapping efficiency between the pumping beam and the oscillating beam is getting higher, and it also reduces the path of heat conductivity. The maximum output power under CW operation is 6W with 85% output coupler, and its slope efficiency is 31.78%. The M2 value of the cavity mode is about 1.69. The focal length of thermal lens is 25cm. The active Q-switched system provides high repetition rate that can increase the signal to noise ratio. It increases the accuracy and simplify the optical measurement. The maximum output energy under pulse operation is 559uJ and the pulse width is 8.7ns with a 70% reflectance output coupler. The self-design water-cooling system could conduct the heat from the gain medium and AO crystal efficiently, so that the laser output power could sustain stable.

Chapter 1

[1]. L. F. Johnson, G. D. Boyd, K. Nassau, and R. R. Soden, Phys Rev. 126, 1406 (1962).
[2]. J. E. Geusic, H. M. Marcos, and L. G. Van Uitert, Appl. Phys. Lett. 4, 182 (1964)
[3]. J. E. Geusic, M. L. Hensel, and R. G. Smith, Appl. Phys. Lett. 6, 175 (1965)
[4]. M. DiDomenico, J. E. Geusic, H. M. Marcos, and R. G. Smith, Appl. Phys. Lett. 8, 180 (1966)
[5]. M. Ross, Proc. IEEE 56, 196 (1968)
[6]. J. Berger, D. F. Welch, D. R. Scifres, W. Streifer, and P. Criss, High Power, High efficient Neodymium:Yttrium Aluminum garnet laser end-pumped by a laser diode array. Appl. Phys. Lett. Vol. 51, pp.1212-1214 (1987)

Chapter 2

[1]. Website of Chemistry department, La Salle University
http://www.lasalle.edu/academ/chem/
[2]. Website of Fujian JDSU CASIX,Inc.
[3]. Walter Koechner “Solid-State Laser Engineering”, 5th rev. and updated ed. Springer (1999).
[4]. Walter Koechner, Michael Bass “Solid-State Lasers”, Springer-Verlag (2003).
[5]. Frank L. Pedrotti, S.J. Leno, and S.Pedrotti, Introduction to Optics
[6]. K. L. Ovanesyanm, A. G. Petrosyan, G. O. Shirinyan, A. A. Avetisyan. “Izv. Akad. Nauk SSSR. Ser, Neorg. Mater. 17, 459-462 (1981) [In Russian]
[7]. Bahaa E. A. Saleh, and Malvin Carl Teich, Fundamentals of Photonics, P.82, 99

Chapter 3

[1]. Instrument Technology Research Center, Introduction to Instrumentation, vol. 5, 1998
[2]. R. Weber, B. Neuenschwander, M. Mac Donald, M. B. Roos, and Heinz P. Weber, “Cooling Schemes for Longitudinally Diode Laser-Pumped Nd:YAG Rods,” IEEE J. Quantum Electron., VOL. 34, NO. 6, JUNE 1998

Chapter 5

[1]. Xiaoyuan Peng, Lei Xu, and Anand Asundi, “Power scaling of Diode-Pump Nd:YVO4 Lasers”, IEEE J. Quantum Electron., VOL. 38, NO. 9, JUNE 2002