基于薄片增益介质的皮秒激光再生放大器研究

近年来,超快激光器已成为激光精密制造的主力光源.为进一步提高激光加工效率和加工能力,需获得更高平均功率、更大单脉冲能量的超短脉冲激光器.本文基于自研的单薄片模块和串接的双薄片模块分别搭建了一套皮秒薄片激光再生放大器,其中基于单薄片模块的再生放大器采用脉宽小于10 ps的种子源,最终获得平均功率44.2 W、脉冲宽度9....     

LD侧泵浦Nd：YAG板条双程功率放大器初步研究

对二极管激光侧泵浦Nd：YAG板条双程功率放大器进行了初步的研究,给出了激光器的数值模拟结果,建立了二极管侧面泵浦Nd:YAG板条激光主振荡-多程放大(MOPA)系统;在100Hz重复频率时,实验获得单脉冲能量为51.9mJ的输出,光束质量M2小于2,脉冲能量起伏小于2%, 实验结果与数值计算结果相符合。     

LD侧泵浦Nd：YAG板条双程功率放大器初步研究

 对二极管激光侧泵浦Nd：YAG板条双程功率放大器进行了初步的研究,给出了激光器的数值模拟结果,建立了二极管侧面泵浦Nd:YAG板条激光主振荡-多程放大(MOPA)系统;在100Hz重复频率时,实验获得单脉冲能量为51.9mJ的输出,光束质量M ²小于2,脉冲能量起伏小于2%, 实验结果与数值计算结果相符合。     

板条激光放大器中寄生振荡的研究

寄生振荡的存在使得放大器在信号光到达之前消耗了大量的反转粒子数,降低了放大器的激光增益和储能效率,严重地影响了激光放大器的性能,尤其对高功率激光放大器。在理论分析和实验研究的基础上,以Nd∶YAG晶体板条为例,用8条半导体激光阵列对晶体进行双侧抽运,研究了高功率激光放大器的寄生振荡现象,分析了板条晶体寄生振荡产生的原因,并详细比较了晶体在不同的抽运功率和表面处理下的放大效果,得到了2倍的单程放大,当输入能量为140 mJ时,获得了278 mJ的激光输出。     

一种新型皮秒单横模Nd:YAG倍频激光器

西安光机所瞬态光学技术国家重点实验室全息测量技术组研制成功的新型"皮秒(ps)单横模Nd:YAG倍频激光器"于4月15日通过验收专家组和我所质检部门检测验收,已交付用户单位使用。6月19日通过用户现场测试,参数与所内验收测试结果相同。     

高功率皮秒紫外激光器新进展

高功率皮秒紫外激光器在高精密加工、激光医疗、光电对抗和光伏产业等领域有重要应用,近年来成为固体激光新光源研究热点。本文对国内外基于和频技术的高功率皮秒紫外激光器研究新进展进行了归纳和总结。首先,阐述了和频工作原理,介绍了和频产生皮秒紫外激光的非线性晶体;然后,介绍了国内外高功率皮秒紫外激光器的新进展,包括:高功率皮秒紫外激光器、高峰值功率皮秒紫外激光器、高功率和高峰值功率皮秒紫外激光器。最后,展望了高功率皮秒紫外激光器的进一步发展及应用。归纳和总结表明:高功率皮秒紫外激光器在国外较成熟,国内在该领域的研究刚刚起步。光子晶体光纤和碟片激光器输出基频光的皮秒紫外激光器有突出的优势,已成为皮秒紫外激光产业的主力军。     

二极管激光侧面泵浦腔同人倍频Nd：YAG板条激光顺研究

用准连续６０Ｗ的二极管激光列阵侧面泵浦“之”字形Ｎｄ：ＹＡＧ板条激光器，当泵浦功率为４５Ｗ，脉宽为４００μｓ时，得到３．５ｍＪ的激光输出。用ＫＤ．Ｐ电光开关调Ｑ，得到１８ｎｓ、２ｍＪ的脉冲激光输出，用ＫＴＰ晶体作腔内倍频，得到１５ｎｓ、０．８５ｍＪ的二次谐波激光输出。     

SESAM实现Nd:YAG激光器被动锁模研究及皮秒脉冲测量

分析了1.06 μm半导体可饱和吸收镜(SESAM)结构及被动锁模基本原理,利用SESAM实现了脉冲式Nd:YAG激光器1.06μm激光的被动锁模,获得了稳定的皮秒激光脉冲序列输出,脉冲序列的能量为45mJ.实验上还研究了腔长对SESAM锁模效果的影响.提出一种基于迈克耳逊干涉仪的皮秒光脉冲测量方法--二次谐波自相关单次测量法,分析这种测量方法的原理并构建实验装置对SESAM被动锁模Nd:YAG激光器的皮秒激光脉冲进行测量,测得激光脉冲宽度为43.6 ps.二次谐波单次测量法具有精度较高,操作简单等优点.     

高效紧凑室温Yb:YAG板条全固态激光技术研究

报道了高效紧凑室温Yb:YAG板条全固态激光研究进展。建立了室温Yb板条激光动力学模型,分析了泵浦激光通量和注入激光亮度与光光效率的关系,以及板条边缘效应抑制方法。实验获得了输出功率22.3 kW、光光效率36%和光束质量优于2.4倍衍射极限的激光输出,为更高功率的Yb板条激光关键技术研究及开发小型化、轻量化、实用化的高功率激光器奠定了基础。     

大理石文物样品皮秒激光清洗实验研究

随着超快激光“冷加工”技术的发展,超快激光逐渐开始应用于文物保护领域。针对古城墙文物表面污染物清洗的应用需求,制作类城墙的大理石文物及表面污染物模拟样品,进行基于皮秒激光的文物样品清洗实验研究,并与纳秒激光清洗的效果进行对比。实验中采用共聚焦显微镜观测和荧光能谱仪成分分析等手段,改变激光输出能量,清洗次数和扫描速度等激光清洗参数,在不损伤大理石基底并综合考虑清洗效率和清洗效果基础上,寻找优化实验参数。实验发现皮秒激光清洗优化参数为激光功率18W,扫描速度1000mm/s,清洗次数8次。清洗后主要污染物硫元素占比下降94.57%,清洗后区域表面粗糙度为1.267μm。综合考虑清洗后污染物成分占比、表面粗糙度等方面,皮秒激光清洗大理石文物样品的整体效果优于纳秒激光清洗区域。     

250 mJ, self-adaptive, diode-side-pumped Nd:YAG slab laser

A scheme of self-adaptive, closed-loop, diode-side-pumped Nd:YAG slab laser was presented. As a result of four-wave mixing of standing waves intersecting at a small angle in a closed-loop cavity, the self-adaptive process of beam cleaning leading to fundamental mode operation despite severe asymmetry of the inversion profile and thermal-optical distortion was achieved. The output beam was extracted from the cavity as the first- order diffraction beam on the dynamic gain gratings created in an active medium. The near-diffraction-limited (parameter M(2)<1.4, divergence of 1 mrad) output beam of 250 mJ energy and the optical slope efficiency of 30% at a repetition rate of up to 25 Hz in a free-running regime were demonstrated.     

Flash-lamp-pumped picosecond Nd:YAG regenerative amplifier

A flash-lamp-pumped Nd:YAG regenerative amplifier has been developed at 1.06 μm, seeded with 10-ps pulses from a diode-end-pumped and mode-locked Nd:YAG oscillator with homemade semiconductor saturable absorber mirror(SESAM).     

High-energy long-pulse Nd:YAG picosecond laser

A long train of actively mode-locked pulses is obtained from a negative feedback controlled Nd:YAG laser. The 70s pulse train contains up to 0.1 J energy and the duration of the picosecond pulses is 120 ps. The laser is operated at a repetition rate of 20 Hz. ActiveQ-control of the cavity generates a short pulse train of duration 50 to 70 ns. An excellent peak-to-background intensity ratio of the correlation function for the picosecond pulses in the train of 5×10³ is reported.     

Compact corner-pumped Nd:YAG/YAG composite slab laser

Corner-pumping is a new pumping scheme in diode-pumped all-solid-state lasers, having such advantages as high pump efficiency, favorable pump uniformity and low cost. Compact corner-pumped Nd:YAG/YAG composite slab lasers at 1064 nm with low or medium output powers and high efficiency are demonstrated in this paper. Combined with intracavity frequency doubling by a LBO crystal, a corner-pumped Nd:YAG/YAG composite slab 532 nm green laser with a stable output is realized successfully. The experimental results show that corner-pumping can reduce laser costs greatly, release the thermal effects of slab crystals and improve the output beam quality, and that the new pumping scheme is feasible in the design of diode-pumped all-solid-state lasers with low or medium output powers.     

Efficient corner-pumped Nd:YAG/YAG composite slab laser

A corner-pumped type is a new pumping type in the diode-pumped all-solid-state lasers, which has the advantages of high pump efficiency and favourable pump uniformity. A highly efficient corner-pumped Nd:YAG/YAG composite slab laser is demonstrated in this paper. The maximal continuous-wave output power of the 1064~nm laser is up to 18.57~W with a slope efficiency and an optical-to-optical conversion efficiency of 44.9{\%} and 39.8{\%}, respectively. Inserting an acousto-optic $Q$-switch in the cavity, the highest average output power of the quasi-continuous wave 1064~nm laser of 6.73~W is obtained at a repetition rate of 9.26~kHz. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped all-solid-state lasers with low or medium output powers.     

Laser-diode-pumped zigzag slab Nd:YAG master oscillator power amplifier

A high-repetition rate master oscillator power amplifier pumped with laser diodes (LDs) is reported. An injection seeding single-frequency electro-optical Q-switched Nd:YAG laser is used as an oscillator, and a conductively cooled Nd:YAG zigzag slab with a bounce-pumped architecture is utilized as a power amplifier. Pulse energies of over 800 mJ at 1 064 nm and 400 mJ at 532 nm, corresponding to average powers of 200 and 100 W, respectively, are achieved with a 12.6-ns pulse width at 250 Hz. Output frequency fluctuations and single-frequency operation are further monitored. Experimental results reveal that the proposed system, which features a single-pass amplified configuration, is a promising design for space-based applications.     

Efficient multiple-longitudinally diode laser pumped Nd:YAG slab laser

The operation of an eightfold longitudinally diode laser pumped 1.06m cw Nd:YAG slab laser is demonstrated. The 809 nm diode radiation is focused through a dichroic coating into each laser channel starting from the reflection points of the 1.06m beam in the slab crystal. At an absorbed pump power in the crystal of 2830 mW a maximum cw TEM₀₀ output of 1075 mW was achieved with a corresponding slope efficiency of 42.5%.     

Picosecond Nd:YLF five-passes laser amplifier with 20 mJ pulse energy

We have demonstrated an all-diode-pumped Nd:YLF laser amplifier that produces 20.8 mJ pulses of 12.9 ps duration at 10 Hz repetition rate. The laser system consists of a mode-locking oscillator, a regenerative amplifier and a five-pass amplifier. The small-angle off-axis five-pass configuration combining with the gradual expansion of the laser beam cross section makes the amplifier compact and effective.