珠宝雕刻用LD泵浦被动Q开关YAG激光器研究

报道了利用连续激光二极管端面泵浦被动Q开关固体Nd:YAG激光器,研究设计了实用光学耦合系统,采用初始信号透过率为80%的Cr4+:YAG晶体实现被动调Q,采用平凹直线腔结构,高重复率调Q激光器中获得了稳定的1064nm窄脉冲激光输出.当泵浦功率为5W,重复率为5kHz时,获得的输出单脉冲能量平均为118μJ,脉冲宽度5 ns,光-光转换效率为15.7%.此性能激光器可用于珠宝雕刻等领域.     

衍射极限的掺钕钇铝石榴石激光器

本文报导一种以掺钕钇铝石榴石为工作物质的激光器,其输出光束达衍射极限。输出脉宽为6～7毫微秒(FWHM),光谱宽度约为0.35埃(FWHM),最高输出达60毫焦耳,偏振度达98％,重复率为1次/秒。激光谐振腔采用平凸非稳定腔结构。     

Two-frequency injection-seeded Nd:YAG laser

Dual longitudinal mode (DLM) operation of a Nd:YAG laser is achieved by simultaneously injection seeding with two seed frequencies. We show that the relative energy in the two frequency components can be adjusted by varying the relative seed power, and that they have excellent spatial, angular, and temporal overlap. The result is a deeply modulated 1.06-μm pulse with a modulation frequency that can be tuned from 185 MHz to at least 17 GHz in 185 MHz increments. In addition to the two seeded frequencies, weak sidebands are also observed in the output spectra. Their energy content is typically less than 1% of that of the seeded modes. We discuss mechanisms which might cause them     

板条型脉冲Nd∶YAG激光器的研究

本文研制了尺寸为124×12×6mm~3的Nd:YAG晶体板条型脉冲激光器,自由振荡单脉冲输出24J,器件总体效率2.5％,电光调Q单脉冲输出860mJ,脉宽12～15ns,Q开关效率72％。     

二极管端泵浦Nd：YAG连续激光器

我们研制了一台二极管连续端泵浦的Ｎｄ：ＹＡＧ激光器，用国产激光二极管作泵浦源，泵浦激光波长为０．８０８μｍ。激光介质为φ５×５ｍｍ的Ｎｄ：ＹＡＧ棒，输出激光波长为１．０６μｍ，用ＣＣＤ相机和图象处理系统记录和分析激光光斑，得到激光横模为ＴＥＭ００模，当输入谐振腔的泵浦功率为２２５ｍＷ时，输出连续激光功率最高达７６．４ｍＷ，光－光转移效率为３３．９％，电光斜效率达到９．１％，并做了腔外倍频实验。     

Single-diode end-pumped Nd:YAG laser

Experimental results on the first miniature Nd:YAG laser end-pumped by a single incoherent infrared-emitting diode are given. Laser operation was verified by measurements of relaxation oscillations, angular divergence, wavelength, and nonlinear output. In order to emit in the 0.81- μm pump band of Nd:YAG, the GaAs1-xPxdiode required cooling to 88 K (-185°C). Cooling the diode increased its efficiency while cooling the rod decreased the pump power necessary to reach threshold. With both laser mirrors highly reflecting at 1.06 μm, the maximum pulse powerP_{D}^{th}emitted by the diode at threshold was 6.2 ± 1.2 mW. The diode power required for laser threshold at room temperature was derived and compared with more recent experiments. Miniature size and long-lived solid-state components make this laser attractive for further development.     

Nd:YAG laser pumped infrared dye laser

Efficient operation of a high peak power and high-average power infrared dye laser, continuously tunable over the range of 10810-12160 Å, has been achieved by pumping with an Nd:YAG laser. A peak power as high as 4 MW with an average power of 390 MW was obtained.     

Single-axial mode, intracavity doubled Nd:YAG laser

A diode-pumped, single-axial mode, intracavity doubled laser has been demonstrated using a cavity consisting of only two intracavity components, a Brewster angle cut piece of Nd:YAG and a KTP doubling crystal. Up to 4 mW single-ended output power has been obtained for 260 mW incident power on the Nd:YAG. Threshold power was 31 mW of diode power incident on the YAG; thus, single-mode operation was attained at up to ~8.5 times threshold. At the highest power the laser was susceptible to multimode operation due to spatial hole burning effects but below ~5 times threshold reliable single mode operation was achievable     

脉冲稳频Nd∶YAG环行激光器

我们在实现单频行波运转的脉冲Nd∶YAG环行激光器基础上,通过自动搜索补偿和快速稳频环路,获得脉宽为0.7ms,峰值功率大于100W,频漂小于1MHz的1.06μm稳频激光。     

Stabilized efficient single-frequency Nd:YAG laser

It is shown how intracavity etalons can be optimally designed for axial mode selection and frequency stabilization of gas and crystal lasers. Relevant laser parameters, required etalon properties, and expected losses are determined. A simple frequency stabilization scheme based on birefringent etalons is described, which does not require laser modulation. Major problems associated with stable single-frequency operation of solid-state lasers are discussed. Using an optimally designed crystal quartz etalon, a Nd:YAG laser could be stabilized to 10^-7in frequency and 2 percent in amplitude. The linearly polarized single frequency TEM00output was 150 mW, which compares to an unpolarized 12-mode output of 400 mW for the bare laser.     

LED带抽运Nd∶YAG激光器

为了研究抽运光源光谱与增益介质吸收光谱对发光二极管(LED)带抽运激光器输出效率的影响,进一步提高输出效率,将光谱信息引入激光速率方程中,建立了LED带抽运速率方程, 采用该方法对LED带抽运Nd∶YAG激光器进行了理论分析和实验验证。结果表明,利用红外LED对Nd∶YAG激光器进行侧面抽运,当抽运能量为9.1mJ时,取得了能量为607μJ的1064nm激光输出,达到实验中最高的倾斜效率15.5%,此时光转换效率为6.67%;速率方程的计算求解和实验的输出能量二者基本吻合。这一结果对研究提高LED带抽运激光器的输出效率是有帮助的。     

Q开关Nd:YAG激光切割晶体后囊膜

自从1980年Aron-Rosa报道第一篇“应用Nd:YAG激光打开人工晶体植入后的后囊膜”的论文后,引起眼科界很大的反响.在这以前,主要利用眼球色素组织吸收可见光,产生热效应达到光凝固的作用.而调Q-Nd:YAG激光是不可见的近红外光,是由于它的高功率密度,对眼内无色素的半透明或白色组织如晶体囊膜或机化膜进行光学击穿而达到切割组织的作用.我院自1985年10月开始应用于临床.     

准连续TEM00模被动调Q Nd:YAG激光器的研究

采用峰值功率为500 W准连续激光二极管(LD)阵列侧面泵浦Nd:YAG晶体,Cr4+:YAG可饱和吸收体作为被动调Q元件,在重复频率为40 Hz时实现了单脉冲能量为8.24 mJ、脉冲宽度约7 ns的1 064 nm TEM00模调Q激光脉冲输出,脉冲峰值功率达到1.2 MW,从而为主振荡功率放大(MOPA)系统提供高峰值功率、高光束质量的种子源。对泵浦功率和泵浦脉冲宽度对输出脉冲特性的影响进行了实验研究。     

LD抽运锁模Nd:YAG激光器研究

利用Cr4+:YAG和声光锁模器联合对光纤耦合LD抽运Nd:YAG激光器进行主被动锁模,比较和分析了Cr4+:YAG被动锁模,声光锁模器主动锁模及两者联合主被动锁模三种情况下平均输出功率的特性,结果表明主被动联合锁模克服了主动锁模稳定性差、被动锁模输出功率低、锁模不完全的缺点,得到幅值和能量抖动小于±6％、锁模深度100％、脉宽小于410ps、输出平均功率290mW的绿光锁模脉冲。     

Nd:YAG调波长锁模

利用棱镜作色散元件,实现了Nd:YAG 1.052、1.061、1.064和1.073微米等四条谱线的锁模输出,输出波长稳定性的计算和实验结果一致。     

高重复率RTP电光调Q Nd：YAG激光特性研究

RTP(RbTiOPO4)是一种新型电光晶体,具有高电阻率、大电光系数、高抗光伤阈值等优点.成为理想的电光调Q晶体.采用两块4 mm×4 mm×5.3 mm的RTP晶体作为电光开关,实现了高重复率RTP电光调Q Nd:YAG 1 064 mm激光运转,获得了不同重复率、不同输出镜透过率情况下单脉冲能量和脉冲宽度与泵浦能量的依赖关系.随着泵浦能量的增加,脉冲宽度变窄,脉冲能量变大.在相同的泵浦能量下,重复率越大,脉宽越宽,脉冲能量越小.在平面渡近似下,给出了RTP电光调O Nd:YAG激光运转的耦合速率方程,数值求解方程的理论计算与实验结果相符.     

FM-laser operation of the Nd:YAG laser

The FM-laser or frequency-sweeping mode of laser oscillation has been demonstrated in a Nd :YAG 1.06-μ laser with an intracavity LiNbO3phase modulator. The experimental results are in excellent agreement with the theoretical expressionDelta= (DeltaOmega/Deltanu) (delta/pi)where δ= peak single-pass phase retardation in the modulator,DeltaOmega= axial mode spacing,Deltanu=modulator detuning, and Δ=resulting FM index of the laser output. Modulation indices as large asDelta approx 230rad have been obtained, in which case the instantaneous laser frequency is sweeping over a full spectral range of2Delta cdot f_{m} approx 120GHz (≈ 4 cm^-1) at a repetition frequencyf_{m} approx 260MHz, with a time-bandwidth product per periodapprox 2Delta approx 460. The coherently mode-locked spectral bandwidth thus obtained in the FM-laser case is very much wider than can be achieved in the pulsed mode-locked case with the same Nd:YAG laser. Some possible ways of using this broad-band coherent FM spectrum are suggested.     

High power diode-laser-pumped twisted-mode Nd:YAG laser

We describe the design and performance of a high power diode-laser-pumped twisted-mode Nd:YAG laser. Using four high power 1 W diode lasers as pumping, nearly single frequency output power of 950 mW was obtained. Stable single frequency operation was realized with the help of injection locking with a master monolithic ring diode-laser-pumped Nd:YAG laser     

常年性鼻炎Nd∶YAG激光治疗观察

采用Nd∶YAG激光照射筛前神经鼻中隔支,筛前神经外侧支及下鼻中下端游离线治疗血管运动性鼻炎和常年变应性鼻炎共416例,其中血管运动性鼻炎316例,有效285例,无效60例,有效率90%,变应性鼻炎100例,有效40例,无效60例,有效率40%。结果表明,Nd∶YAG激光照射筛前神经,对血管运动性鼻炎疗效好,对变应性鼻炎疗效差。并对作用机理作了初步探讨。