發(fā)布時間：2018-06-14 20:53

  本文選題：高頻電光調(diào)Q + 彈光效應(yīng)��； 參考：《長春理工大學(xué)》2014年博士論文

【摘要】：高速攝影在對高速運動目標(biāo)的姿態(tài)、激光加工過程、化學(xué)反應(yīng)過程等一些快速過程的研究起著非常重要的作用,應(yīng)用前景十分廣闊。在高速攝影中,對照明光源的要求很高,光源的亮度直接影響到攝影的質(zhì)量。高頻電光調(diào)Q激光是高速攝影中優(yōu)選光源之一,本文就滿足高速攝影,以Nd:YAP作為激光工作物質(zhì)的激光系統(tǒng)開展了一系列研究。首先,在研究了Nd:YAP晶體特性、能級結(jié)構(gòu)、吸收光譜、熱效應(yīng)等基礎(chǔ)上,為了深入了解Nd:YAP作為工作物質(zhì)激光器的特性,用圖解法設(shè)計LD泵浦Nd:YAP連續(xù)運轉(zhuǎn)激光器,獲得了重要參數(shù)和數(shù)據(jù)。在此基礎(chǔ)上,開展了燈泵脈沖Nd:YAP激光器理論及實驗研究。設(shè)計了燈泵浦脈沖運轉(zhuǎn)激光器和變換頻率為100k Hz的恒流充電電源,并對影響激光輸出穩(wěn)定性的充電精度進(jìn)行了深入的探討。研制成功了輸出脈沖能量350m J,重復(fù)頻率1Hz,脈沖寬度500μs,輸出波形為方波的Nd:YAP激光器。其次,在激光器研制成功的基礎(chǔ)上,以四能級系統(tǒng)模型為基礎(chǔ),求解四能級調(diào)Q速率方程,結(jié)合泵浦條件,獲得了重復(fù)頻率與調(diào)Q激光器輸出特性之間的關(guān)系。測出重復(fù)頻率在50-150k Hz范圍內(nèi)的激光輸出能量、建立時間、脈沖寬度的試驗曲線,設(shè)計了高頻電光調(diào)Q系統(tǒng)。由于高頻調(diào)Q激光輸出穩(wěn)定性是一直以來最難解決的關(guān)鍵問題,本文對彈光效應(yīng)等因素進(jìn)行了深入分析,采用了有效方法來產(chǎn)生穩(wěn)定的激光脈沖,實現(xiàn)了脈沖透射式(PTM)調(diào)Q,頻率為150k Hz的脈沖序列。最后,在單級調(diào)Q激光器研究的基礎(chǔ)上,為了滿足高速攝影對光源功率的要求,設(shè)計了兩級激光放大器,研制完成了由一級本振加兩級放大的激光系統(tǒng)。并通過倍頻的,獲得了波長為0.532μm,輸出能量為1J的激光輸出。對激光輸出能量的不穩(wěn)定性進(jìn)行理論與試驗研究,解決各類不穩(wěn)定因素,使激光輸出的能量和穩(wěn)定性均達(dá)到高速攝影的要求。通過對高速運動目標(biāo)進(jìn)行同步攝影實驗,證明該高頻調(diào)Q激光系統(tǒng)完全滿足高速攝影對光源的要求。
[Abstract]:High-speed photography plays a very important role in the study of some rapid processes such as the attitude of high speed moving target, laser processing, chemical reaction and so on, and the application prospect is very broad. In high-speed photography, the requirement of lighting source is very high, the brightness of light source directly affects the quality of photography. High frequency electro-optic Q-switched laser is one of the best light sources in high speed photography. In this paper, a series of studies have been carried out on the laser system with ND: Yap as the working material for high speed photography. First of all, based on the study of ND: YAP crystal characteristics, energy level structure, absorption spectrum, thermal effect and so on, in order to deeply understand the characteristics of ND: Yap laser as working matter, LD pumped ND: Yap continuous operating laser is designed by graphic method. Important parameters and data are obtained. On this basis, the theoretical and experimental study of lamp pump pulsed ND: YAP laser is carried out. A lamp pumped pulse operating laser and a 100kHz constant current charging power supply are designed, and the charging accuracy which affects the stability of laser output is discussed. ND: YAP laser with output pulse energy 350 m J, repetition rate 1 Hz, pulse width 500 渭 s and square wave output is successfully developed. Secondly, on the basis of the successful development of the laser, based on the four-level system model, the four-level Q-switched rate equation is solved, and the relationship between the repetition rate and the output characteristics of the Q-switched laser is obtained in combination with the pump conditions. The laser output energy at the repetition rate of 50-150 kHz was measured, and the experimental curves of time and pulse width were established. A high-frequency electro-optic Q-switching system was designed. Because the stability of high frequency Q-switched laser output is the most difficult to solve, this paper makes a thorough analysis of the elasto-optical effect and adopts an effective method to produce stable laser pulse. A pulse sequence with a frequency of 150 kHz is realized. Finally, based on the research of single-stage Q-switched laser, a two-stage laser amplifier is designed to meet the requirements of high speed photography for light source power, and a laser system with one stage local vibration and two stage amplification is developed. A laser with a wavelength of 0.532 渭 m and an output energy of 1 J has been obtained by frequency doubling. The instability of laser output energy is studied theoretically and experimentally in order to solve all kinds of unstable factors and make the energy and stability of laser output meet the requirements of high-speed photography. The high frequency Q-switched laser system is proved to meet the requirements of high speed photography.
【學(xué)位授予單位】：長春理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：TB86;TN248
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本文編號：2018927