Passively Q-Switched Nd,Cr:YAG Laser Simultaneous Dual-Wavelength Operation at 946 nm and 1.3μm

A diode-end-pumped Q-switched high-efficiency Nd, Cr：YAG laser with simultaneous dual-wavelength emission at 946nm and 1.3μm is demonstrated. The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%. The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38ns at 946nm and 26.65ns at 1.3μm. A maximum total repetition rate of 43.25 kHz is obtained.

Continuous-Wave and Actively Q-Switched Diode-Pumped Er:LuAG Ring Laser at 1650 nm

We demonstrate a cw and actively Q-switched Er：LuAO laser resonantly dual-end-pumped by 1532nm fibre- coupled laser diodes. A maximum cw output power of 1.9W at 1650.3nm is obtained at a pump power of 25.5 W, corresponding to a slope efficiency of 43.3 %. In the Q-switched regime, the maximum pulse energy of 3.51 mJ is reached at a pulse repetition rate of 100 Hz, a pulse duration of 90.5ns and a pump power of 25.5 W. At the repetition rate of 400 Hz, the output energy is 2.12m J, corresponding to a pulse duration of 125.4 ns.

High-Power Passively Q-Switched Nd:YAG Laser at 1112 nm with a Cr^(4+):YAG Saturable Absorber

A high-power passively Q-switched Nd：YAG laser operating at lll2nm with Cr4＋：yAO as a saturable absorber is demonstrated. Under 808 nm diode-direct pumping, the maximum average output power of 2.73 W is achieved at the pump power of 16.65 W, corresponding to an optical-to-optical conversion efficiency of 16.4%. At the same time, the pulse width, pulse repetition rate, single pulse energy and peak power are 27.2ns, 9 kHz, 303.3#3 and 11.2kW, respectively. As far as we know, the result gives the highest average output power at 1112nm generated by an 808 nm diode-end-pumped Nd：YAG laser.

Efficient Nd:YVO4 laser in-band pumped by wavelength-locked 913.9-nm laser diode and Q-switch operation

An efficient 1064-nm Nd：YVO_4laser in-band pumped by a wavelength-locked laser diode（LD） at 913.9 nm was demonstrated. The maximum continuous wave（CW） output power of 23.4 W at 1064 nm was realized with the incident pump power of 40 W, corresponding to a total optical-to-optical efficiency of 58.5%. This is to the best of our knowledge the highest total optical-to-optical efficiency and output power of Nd：YVO_4laser in-band pumped by a 913.9-nm laser diode.The Q-switched operation of this laser was also investigated. Through a contrast experiment of pumping at 808 nm, the experimental results showed that an Nd：YVO_4laser in-band pumped by a wavelength-locked LD at 913.9 nm had excellent pulse stability and beam quality for high repetition rate Q-switching operation.

Efficient Diode-Pumped Actively Q-Switched Ceramic Nd:YAG/YVO4 Raman Laser Operating at 1657 nm

A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd：YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.

High stability and low noise laser-diode end-pumped Nd:YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-PVA saturable absorber

We report a high repetition frequency, high power stability and low laser noise laser-diode(LD) end-pumped Nd: YAG ceramic passively Q-switched laser at 1123 nm based on a Ti_(3)C_(2)T_(x)-polyvinyl alcohol(PVA) film as a saturable absorber(SA). A Brewster polarizer(BP) and a birefringent crystal(BC) are incorporated to enable frequency selection and filtering for the passively Q-switched 1123 nm pulsed laser to improve the power stability and reduce the noise. When the pump power is 5.1 W, an average output power of 457.9 m W is obtained, corresponding to a repetition frequency of 1.09 MHz,a pulse width of 56 ns, a spectral line width of 0.65 nm, a power instability of ±0.92%, and a laser noise of 0.89%.The successful implementation of the “Ti_(3)C_(2)T_(x)-PVA film passively Q-switching” combined with “frequency selection and filtering of BP + BC” technology path provides a valuable reference for developing pulsed laser with high repetition frequency, high stability and low noise.

Er^3+,Yb^3+:glass-Co^2+:MgAl2O4 diffusion bonded passively Q-switched laser

A Co^2＋：spinel passively Q-switched erbium-ytterbium-phosphate glass bonded laser pumped at 940 nm is reported.A pulse energy of 210 μJ, a peak power over 70 kW, and beam quality M-2 parameter of 1.2 are obtained under a pump power of 235 mW. An unbonded laser output experiment with the same dimension of the active material and the saturable absorber as the bonded laser output experiment is carried out. The reason why the output in the bonded laser is improved is determined.

Effect of 532 nm Laser Irradiation on Vc Content in Cabbage Seedlings

[ Objective ]The aim of this study was to discuss the feasibility of breeding cabbage with high Vc by 532 nm laser.[ Method ] With the material of cabbage, the embryo of cabbage seeds was irradiated by frequency doubled Nd ：YAG laser with different power densities and time, and the effects of laser mode on functional leaf area, chlorophyll and Vc contents in cabbage seedlings were also studied. [Result] The results showed that functional leaf area and chlorophyll content were related to laser power density and time when laser power density was 2 -20 mW/mm^2, while the optimal effect was observed at 14 mW/mm^2 for 1 min. The content of Vc in cabbage seedlings was related to dosage of laser irradiation when irradiating time ranged from 1 to 5 min, and the optimal effect was observed at 2.8 J （20 mW/mm^2, 3 min）. [Conclusion] Irradiating the embryo of cabbage seeds with proper irradiation dosage of 532 nm laser can increase its effect on the Vc content significantly.

Comparison of laser iridotomy using short duration532-nm Nd: YAG laser (PASCAL) vs conventional laser in dark irides

AIM: To evaluate the outcome of laser iridotomy using532-nm Nd: YAG laser(PASCAL) with short pulse duration and Nd: YAG laser compared to conventional combined laser iridotomy.METHODS: Retrospective, nonrandomized, comparative case series. Forty-five eyes of 34 patients underwent laser iridotomy. Twenty-two eyes underwent iridotomy using short duration PASCAL and Nd: YAG laser, and 23 eyes underwent iridotomy using conventional combined laser method. The average settings of PASCAL were60 μm and 700-900 m W with a short duration of 0.01 s to reduce the total applied energy. The conventional laser was 50 μm and 700-900 m W for 0.1s. After photocoagulation with these laser, the Nd: YAG laser was added in each group. Endothelial cell counts of preiridotomy and 2mo after iridotomy were measured and compared.RESULTS: All eyes completed iridotomy successfully.The total energy used in the PASCAL group was 1.85 ±1.17 J. Compared to conventional laser 13.25 ±1.67 J, the energy used was very small due to the short exposure time of PASCAL. Endothelial cell counts were reduced by0.88% in the PASCAL group and 6.72% in the conventional laser group(P =0.044). The change in corneal endothelial cell counts before and after iridotomy was significant in conventional combined laser iridotomy group(P =0.004).CONCLUSION: Combined PASCAL and Nd:YAG laseriridotomy is an effective and safe technique in the dark brown irides of Asians. Furthermore, the short duration of exposure in PASCAL offers the advantages of reducing the total energy used and minimizing the corneal damage.

Contemporary review of the 532 nm laser for treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia(BPH)is a condition that occurs increasingly with age.The established gold standard treatment for BPH has been the electrocautery-based transurethral resection of the prostate(TURP).TURP,however,is associated with several complications and side effects.Therefore,there is an increasing interest in a number of emerging minimally invasive therapies as alterative treatment options.Laser therapy using the Greenlight laser is a promising alternative to the traditional TURP.Selective absorption by hemoglobin allows rapid,hemostatic vaporization of prostate tissue.Additional advantages include avoidance or minimization of complications such as intraoperative fluid absorption,and bleeding,retrograde ejaculation,impotence,and incontinence,as well as its use in treating high volume BPH.We review the use of the Greenlight laser in the treatment of BPH,when comparing complications and advantages in relation to TURP.

Double Q-switched 946 nm laser with MgO：LN electro-optic crystal and MoSe2 saturable absorber

We report a double Q-switched 946 nm laser with a magnesium-oxide-doped LiNbO3 （MgO：LN） electro-optic （EO） crystal and a monolayer molybdenum diselenide （MoSe2） saturable absorber （SA）. A pulsed laser diode side-pumped long neodymium-doped yttrium aluminum garnet rod （φ3×65 mm） is used as the gain medium. Large pulse energy up to 3.15 mJ and peak power up to 346 kW are generated at the repetition rate of 550 Hz, corresponding to the beam quality factors of Mx^2=3.849, My^2=3.868. Monolayer MoSe2 nanosheets applied in the experiment would be a promising SA for a passive Q-switching operation.

强脉冲光联合Q开关倍频Nd:YAG 532nm激光治疗面部雀斑疗效观察

目的:观察强脉冲光联合Q开关倍频Nd:YAG 532nm激光治疗面部雀斑的临床效果。方法:选取笔者医院2017年5月-2019年5月收治的126例雀斑患者,随机分为观察组和对照组,每组63例。对照组采用强脉冲光治疗,观察组采用强脉冲光联合Q开关倍频Nd:YAG 532nm激光治疗,观察两组治疗后的临床效果。结果:观察组临床总有效率明显高于对照组(χ^2=12.86,P<0.01),观察组治疗总次数明显低于对照组(t=3.928,P<0.05),复发率也明显低于对照组(χ^2=4.189,P<0.05),患者对治疗满意度明显高于对照组(χ^2=13.945,P<0.01),两组不良反应发生率无明显差异(χ^2=0.099,P>0.05)。结论:强脉冲光联合Q开关倍频Nd:YAG 532nm激光治疗雀斑复发率低、治疗次数少、安全性高,临床效果显著,值得在临床上推广使用。

Line-narrowed electro-optic periodically-poled-lithium-niobate Q-switched laser with intra-cavity optical parametric oscillation using a grazing-incidence grating

We report a line-narrowed electro-optic periodically-poled-lithium-niobate （PPLN） Q-switched laser with intra-cavity optical parametric oscillation using a grazing-incidence grating, producing 8-ns, 5-#J pulses at 10-kHz repetition rate when pumped with a 10-W diode laser at 808 rim. The output wavelength is centered at 1554.3 nm with a 0.03-nm spectral width. Wavelength tuning is achieved by rotating a mirror and changing the crystal temperature.

LD-pumped acousto-optic 2-switched Pr:YLF pulsed laser at 604 nm

We demonstrated an actively acousto-optic Q-switched pulsed laser based on Pr:YLF at 604 nm.A 604 nm continuous-wave(CW)laser with a maximum output power of 3.84 W was achieved for the first time,to the best of our knowledge.The Q-switched laser with a maximum average output power of 0.384 W,a narrowest pulse duration of 44.5 ns,a maximum single pulse energy of~64.1μJ,and a maximum peak power of~1.44 kW was obtained at a repetition rate of 6 kHz.As far as we know,this was the first report of such a narrow pulse duration,high-power,and high-energy Q-switched pulsed laser at604 nm.The beam quality factors M_(x)^(2)and M_(y)^(2)were measured to be 2.87 and 2.40,respectively.The results show that acousto-optic Q-switching is a promising method for obtaining pulsed lasers.

调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病的疗效及对患者生活质量的影响

目的:探讨调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病患者的临床效果。方法:采用单中心临床试验研究方法,选取2019年6月30日-2022年12月31日在笔者医院接受治疗的186例面部脂溢性角化病患者进行随机分组,其中联合组93例患者采用调Q 532 nm激光联合超脉冲CO_(2)激光治疗,对照组93例患者采用超脉冲CO_(2)激光治疗,对比两组患者治疗前后的临床疗效、皮肤病生活质量指数(Dermatology Life Quality Index,DLQI)评分、并发症的发生情况。结果:联合组疗效优于对照组(P<0.05);治疗后,两组衣物选择评分、患者的日常活动评分、症状与躯体感受评分、心理感受程度评分方面及DLQI总分均低于治疗前(均P<0.05),且联合组改善均优于对照组(均P<0.05)。两组并发症率比较,差异无统计学意义(P>0.05)。结论:调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病患者较单纯采用超脉冲CO_(2)激光治疗具有更好的效果,能更有效地改善患者的生存质量。

浮法玻璃532 nm纳秒激光切孔缺陷研究

利用532 nm纳秒激光通过自下而上螺旋线的扫描方式可实现浮法玻璃高效切孔,但纳秒激光作用于玻璃时的明显热效应将使玻璃在激光切孔过程中产生崩边、孔壁表面白斑、表面微观裂纹和凹坑等缺陷行为。围绕该问题,本文通过单因素试验方法,探究了532 nm纳秒激光切孔缺陷行为。结果表明,激光脉冲频率是影响缺陷形态的关键因素,不合适的脉冲频率与脉冲能量会严重增大玻璃孔边缘崩边情况以及孔壁表面粗糙度,同时产生不均匀区域性白斑;增加扫描速度会降低孔壁表面粗糙度;较小螺旋线重叠率会导致玻璃孔壁产生波纹状表面形貌;孔壁质量较差时微观裂纹凹坑更加明显。

532nm激光联合Nd∶YAG激光行虹膜周边切除术的效果分析

目的探究对闭角型青光眼患者实施532 nm激光联合Nd∶YAG激光行虹膜周边切除术的作用。方法方便选取2020年1月—2023年12月宜兴市中医医院收治的82例闭角型青光眼患者为研究对象,采用盲摸双色球法分为观察组和参照组,各41例。参照组单独用Nd∶YAG激光行虹膜周边切除术治疗,观察组先给予532 nm激光烧灼虹膜周边隐窝,再使用Nd∶YAG激光行虹膜周边切除术。比较两组手术情况、治疗效果及眼压水平。结果观察组激光总点数、激光能量及虹膜一次穿透率明显优于参照组,差异有统计学意义(P均<0.05)。观察组治疗总有效率(97.56%)高于参照组(82.93%),差异有统计学意义(χ^(2)=4.987,P<0.05)。观察组术后1 h、术后7 d眼压水平明显优于参照组,差异有统计学意义(P均<0.05)。结论532 nm激光联合Nd∶YAG激光行虹膜周边切除术能够明显改善青光眼患者的手术情况、提高治疗效果,眼压得到明显降低。

羟苯磺酸钙辅助532 nm眼底激光对糖尿病视网膜病变患者黄斑厚度及视网膜新生血管荧光素渗漏面积的影响

目的探讨羟苯磺酸钙辅助532 nm眼底激光对糖尿病视网膜病变(DR)患者的影响。方法以2020年5月—2023年5月于我院门诊和住院治疗的150例DR患者为研究对象,按照随机数字表法将其分为对照组和观察组,各75例。对照组实施532 nm眼底激光治疗,观察组在对照且基础上加用羟苯磺酸钙治疗。比较两组视力水平、视网膜新生血管荧光素渗漏面积、黄斑厚度、生活质量、并发症发生情况。结果治疗后,观察组视网膜新生血管荧光素渗漏面积(2.78±0.55)mm^(2)小于对照组,黄斑厚度(305.12±38.46)μm薄于对照组,视力水平(0.75±0.21)及世界卫生组织生存质量测定量表中的环境领域评分(79.88±6.42)分、心理领域评分(80.66±6.97)分、社会关系领域评分(82.13±6.73)分、生理领域评分(79.84±6.63)分均高于对照组,组间差异有统计学意义(P<0.05)。两组并发症发生率比较,差异无统计学意义(P>0.05)。结论羟苯磺酸钙辅助532 nm眼底激光治疗,可明显缩减黄斑厚度,减小渗漏面积,有助于视力改善,且安全性高。

532nm和808nm激光及其线偏振激光辐照人正常膀胱与膀胱癌组织光学特性

采用双积分球系统和光辐射测量技术的基本原理 ,以及运用生物组织的光学模型 ,研究了 5 32nm和80 8nm激光及其线偏振激光辐照人正常膀胱和膀胱癌组织的光学特性 .结果表明 :膀胱癌组织对同一波长的激光或其线偏振激光的衰减明显较正常膀胱组织的要大 ,膀胱癌组织对 5 32nm和 80 8nm激光的衰减均较其线偏振激光的要略大一些 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的衰减明显较正常膀胱组织的要大 .正常膀胱或膀胱癌组织对同一波长的激光及其线偏振激光的折射率均没有明显的差异 ,膀胱癌组织对 5 32nm和80 8nm激光的折射率比正常膀胱的明显要大 .Kubelka Munk二流模型下 ,两种组织对同一波长的激光或其线偏振激光的光学特性均有显著性差异 (P <0 0 1) .同一组织对不同波长的激光及其线偏振激光的光学特性也有显著性差异 (P <0 0 1) ,正常膀胱组织对同一波长的激光及其线偏振激光的光学性有明显差异 ,而膀胱癌组织对同一波长的激光及其线偏振激光的光学特性则没有明显差异 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的前向散射通量i (x)、后向散射通量 j (x)、总散射通量I (x)的衰减均较正常膀胱组织的明显要大得多 ,且其i (x)均明显较j (x)

532nm连续激光对砷化镓材料损伤的研究

利用532 nm连续激光对掺Si的n型砷化镓材料进行作用,材料的晶轴方向为<100>偏<111A>方向15°。实验观察到,连续激光与材料相互作用过程中,材料作用表面的反射光在观察屏上形成环状结构,认为是由夫琅和费衍射产生的,并首次提出将衍射作为探测材料损伤的方法。实验测得砷化镓的阈值损伤功率密度为2.56×10~5 W/cm^2。利用温度场的热传导方程计算获得材料的损伤阈值时间与入射光功率密度的关系曲线,并与实验曲线进行了比较。