Large-field objective lens for multi-wavelength microscopy at mesoscale and submicron resolution

Conventional microscopes designed for submicron resolution in biological research are hindered by a limited field of view,typically around 1 mm.This restriction poses a challenge when attempting to simultaneously analyze various parts of a sample,such as different brain areas.In addition,conventional objective lenses struggle to perform consistently across the required range of wavelengths for brain imaging in vivo.Here we present a novel mesoscopic objective lens with an impressive field of view of 8 mm,a numerical aperture of 0.5,and a working wavelength range from 400 to 1000 nm.We achieved a resolution of 0.74μm in fluorescent beads imaging.The versatility of this lens was further demonstrated through high-quality images of mouse brain and kidney sections in a wide-field imaging system,a confocal laser scanning system,and a two-photon imaging system.This mesoscopic objective lens holds immense promise for advancing multi-wavelength imaging of large fields of view at high resolution.

Study of Krypton Laser-Induced Choroidal Neovascularization in a Guinea Pig Model of High Anisometropia

Purpose:To investigate the association between high anisometropia and the area of choroidal neovascularization (CNV) induced by krypton laser in guinea pigs and better understand the pathogenesis and prevention of myopic CNV. Methods:.Nine 3-week old male guinea pigs with anisometropia > 6.00D were randomly assigned to three groups according to examination date after laser photocoagulation (7d, 14d and 28d). All animals underwent refraction. The eye with higher myopia was used as the experimental eye, and the other as the control eye..All eyes received repeated multi-wavelength krypton laser photocoagulation treatments (wavelength: 532 nm; laser power: 400 mW; spot diameter: 50 μm; exposure time: 0.1s). Fundus photography and indocyanine green angiography (ICGA) were performed. Afterwards, the animals were sacrificed immediately,.and the eyes were enucleated and processed for histopathologic examination and flat mounts. Results: CNV appeared at 7d after laser treatment. The area of CNV peaked at 14d, and decrease in area and the presence of scarring was noted at 28 d..CNV was present in 66.7% of eyes by ICGA at 14 d..CNV could be observed under light microscopy at all three time points..At 14 d,.flat mount showed the neovascular plexus around the lesion. Semi-quantitative analysis revealed that the area of CNV in treated eyes was greater than that of control eyes. Conclusion:.Since the mechanism of CNV in this study resembles that of CNV in pathological myopia, this model can be used to investigate the etiology, pathogenesis and treatment of CNV in pathological myopia.

Terahertz Generation Using Implanted InGaAs Photomixers and Multi-wavelength Quantum Dot Lasers

We report on a study of terahertz(THz) generation using implanted In Ga As photomixers and multi-wavelength quantum dot lasers. We carry out In Ga As materials growth, optical characterization, device design and fabrication, and photomixing experiments. This approach is capable of generating a comb of electromagnetic radiation from microwave to terahertz. For shortening photomixer carrier lifetime, we employ proton implantation into an epitaxial layer of lattice matched In Ga As grown on InP. Under a 1.55 μm multimode In GaAs/In GaAsP quantum dot laser excitation, a frequency comb with a constant frequency spacing of 50 GHz generated on the photomixer is measured, which corresponds to the beats of the laser longitudinal modes. The measurement is performed with a Fourier transform infrared spectrometer. This approach affords a convenient method to achieve a broadband multi-peak coherent THz source.

Multi-wavelength continuous-wave Nd:YVO4 self-Raman laser under in-band pumping

Multi-wavelength continuous-wave self-Raman laser with an a-cut composite YVO4/Nd:YVO4/YVO4 crystal pumped by an 879-nm wavelength-locked laser diode is demonstrated for the first time.Multi-wavelength Raman lasers at 1168.4,1176,1178.7,and 1201.6 nm are achieved by the first Stokes shift of the multi-wavelength fundamental lasers at 1064,1066.7,1073.6,1084,and 1085.6 nm with two Raman shifts of 890 and 816 cm^-1.A maximum Raman output power of 2.56 W is achieved through the use of a 20-mm-long composite crystal,with a corresponding optical conversion efficiency of 9.8%.The polarization directions of different fundamental and Raman lasers are investigated and found to be orthogonalπandσpolarizations.These orthogonally polarized multi-wavelength lasers with small wavelength separation pave the way to the development of a potential laser source for application in spectral analysis,laser radar and THz generation.

Multi-wavelength laser active coherent combination

A seed laser oscillating at different frequencies is proved to have the potential to mitigate the stimulated Brillouin scattering（SBS） effect in a fiber amplifier,which may increase the emission power of a coherent beam combination（CBC） system greatly.In this study,a basic mathematical model describing the multi-wavelength CBC is proposed on the fundamentals of CBC.A useful method for estimating the combination effect and analysing the feasibility and the validity of the multi-wavelength coherent combination is provided.In the numerical analysis,accordant results with four-wavelength four-channel CBC experiments are obtained.Through calculations of some examples with certain spectra,the unanticipated excellent combination effect with a few frequencies involved is explained,and the dependence of the combination effect on the variance of the amplifier chain length and the channel number is clarified.

Theoretical study of the enhancement of saturable absorption of Kr under x-ray free-electron laser

The generation of hollow atoms will reduce the probability of light absorption and provide a high-quality diffraction image in the experiment. In this paper, we calculated the ionization rate of the Kr atom under x-ray free-electron laser(XFEL) using Hartree–Fock–Slater model and simulated the ionization model of Kr atom using Monte–Carlo method to determine the response of the hollow atom of Kr atom to the XFEL photon energy. Calculating the correlation between the total photoionization cross-section of the ground state of Kr atom and the photon energy, we determined three particular photon energies of 1.75 ke V, 1.90 ke V, and 14.30 ke V. The dynamics simulation under the experimental condition's17.50 ke V photon energy was achieved by implementing the Monte–Carlo method and calibrating the photon flux modeling parameters. Consequently, our calculated data are more consistent with experimental phenomena than previous theoretical studies. The saturable absorption of Kr at 1.75 ke V, 1.90 ke V, 14.30 ke V, and 17.50 ke V energies was further investigated by using the optimized photon flux model theory. We compared the statistics on main ionization paths under those four specific photon energies and calculated the population changes of various Kr hollow atoms with different configurations.The results demonstrate that the population of hollow atoms produced at the critical ionization photon energy is high. Furthermore, the change of population with respect to position is smooth, which shows a significant difference between the generation mode of ions with low and high photon energies. The result is important for the study of medium-and high-Z element hollow atoms, which has substantial implications for the study of hollow atoms with medium and high charge states, as well as for the scaling of photon energy of free electron lasers.

Switching,explosion,and chaos of multi-wavelength soliton states in ultrafast fiber lasers

Because of the complexity and difficulty of realizing a multi-wavelength soliton state,reports on its internal dynamic characteristics are scarce.In this study,the switching and periodic soliton explosion processes of the multi-wavelength soliton state in a negative dispersion passively mode-locked fiber laser are realized.The generation of the multi-wavelength soliton state undergoes the process of noise,oscillation,and stable mode-locking,and the splitting and annihilation of solitons with different group velocities directly impact the generation and disappearance of three wavelengths.Positive and negative dispersion lead to different group velocities of solitons.The presence and displacement of solitons with different group velocities cause soliton collisions,which lead to soliton explosions.A soliton experiences relative phase oscillation,chaos,and oscillation,as well as convergence and separation before and after an explosion.With an increase in parameters related to pump power,single-soliton oscillation,multi-wavelength solitons,and chaos are found in experiments and simulations,proving the relevance and reliability between simulation and experimental results.This work promotes the dynamical study of multi-soliton collisions in nonlinear science and the development of chaos theory in multi-comb lasers.

Laser treatment in 341 patients with exudative agerelated macular degeneration

AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A total of 392 eyes of 341 patients with exudative AMD were examined.77.6% had choroideal neovascularisation(CNV).Before the use of indocyanine green(ICG) angiography,occult CNV was detected in only 1.8% of the eyes,but after the use of ICG angiography,this increased to 19.5%(P<0.001).Of the 349 eyes which were followed up,visual acuity had remained stable in 68.2% of the eyes.There was a statistically significant relationship between localisation of lesion and visual acuity changes on pre-and post-laser treatment(P<0.001).Also there was a statistically significant relationship between localisation of lesion and recurrence(P<0.05).The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.· CONCLUSION:ICG angiography is highly important in the treatment of occult CNV.

Demonstration of a diode-pumped dual-wavelength metastable krypton laser

Diode-pumped rare gas lasers are potential candidates for high-energy and high-beam quality laser systems.Currently,most investigations are focused on metastable Ar lasers.The Kr system has the unique advantages of higher quantum efficiency and lower discharge requirements for comparison.In this paper,a diode-pumped metastable Kr laser was demonstrated for the first time.Using a repetitively pulsed discharge at a Kr/He pressure of up to approximately1500 Torr,metastable Kr atoms of more than 10^(13)cm^(-3)were generated.Under diode pumping,the laser realized a dual-wavelength output with an average output power of approximately 100 mW and an optical conversion efficiency of approximately 10% with respect to the absorbed pump power.A kinetics study involving population distribution and evolution was conducted to analyze the laser performance.

多波长氪激光治疗不同分期糖尿病视网膜病变

目的探讨多波长氪激光治疗不同分期糖尿病视网膜病变的临床疗效。方法60例110眼糖尿病视网膜病变(DR)患者,其中增殖前期糖尿病视网膜病变(PPDR)18眼,早期增殖期糖尿病视网膜病变(PDR)58眼,高危PDR34眼,依病变程度行次全视网膜光凝术、标准全视网膜光凝术和超全视网膜光凝术。术后随访6～32个月,观察视网膜光凝后患者的视力、眼底及荧光血管造影变化。结果治疗后PPDR患者、早期PDR患者视力提高或不变者分别占88.9%、87.9%,均显著高于高危PDR患者的73.5%(P值均<0.05)。初次视网膜光凝后,PPDR患者、早期PDR患者的有效率分别为94.5%、91.3%,均显著高危PDR患者的41.1%(P值均<0.05)。结论多波长氪激光治疗不同分期糖尿病视网膜病变有效,且PPDR和早期PDR治疗效果好。

加减驻景方对实验性脉络膜新生血管的作用研究

目的观察加减驻景方对实验性脉络膜新生血管(choroidal neovascularization,CNV)的干预作用,试图为脉络膜新生血管相关疾病的治疗提供中药治疗方案。方法将氪激光诱导发生脉络膜新生血管的3周大雌性三色豚鼠50只(50只眼)随机分为5组:中药预防组,中药高剂量组,中药中剂量组,中药低剂量组,模型组(生理盐水),每组10只。采用多波长氪激光(532 nm)对豚鼠左眼行视网膜光凝,激光功率、光斑直径、曝光时间分别为120～180 mw、50μm、0.1 s,每只眼在视盘下方行10个光斑斑点。预防组于激光前1周开始给药,高、中、低剂量组于光凝后24 h开始给药,预防组给药共28 d,高、中、低剂量组给药21 d。给药方式为每天1次灌胃给药。给药后全部行眼底彩照、吲哚菁绿血管造影(indocyanine green angiography,ICGA)及脉络膜铺片观察。结果 ICGA检查,各组出现荧光的激光斑个数所占比例(CNV发生率)分别为:预防组54%、高剂量组68%、中剂量组66%、低剂量组70%、模型组68%;CNV渗漏面积最大的为模型组(1.262 3±0.3952 5)mm2,其次为中药高剂量组,渗漏最小的为中药预防组,其次为中药中剂量组,中药小剂量组居中,相互之间差异均有统计学意义(P<0.05);脉络膜铺片结果与ICGA检查结果相一致。结论加减驻景方对氪激光诱导的三色豚鼠脉络膜新生血管具有防治作用,预防用药效果最佳。

氪激光与氩激光光凝治疗糖尿病性黄斑水肿的疗效比较

目的：回顾性分析对比氩激光和氪激光光凝治疗糖尿病性黄斑水肿（DME）的疗效。方法：2003-06/2006-06我们选用98例（154眼）黄斑水肿患者随机分为氪、氩激光治疗组治疗，治疗后随诊3-36（平均17.5）mo。结果：氩激光组黄斑水肿消退21眼，部分消退32眼，不变25眼；氪激光组黄斑水肿消退27眼，部分消退37眼，不变12眼，两组疗效比较差异有统计学意义（P〈0.05）。氩激光组视力提高29眼，不变23眼，下降26眼；氪激光组视力提高34眼，不变29眼，下降13眼，两组疗效比较差异有统计学意义（P〈0.05）。结论：在治疗条件基本相同的情况下，氩激光和氪激光都能进行有效的糖尿病性黄斑水肿治疗，氪离子激光治疗黄斑水肿更具有优越性。

脉络膜新生血管动物模型的建立与评估

目的：评价氪激光诱导棕色挪威（brown norwav，BN）大鼠脉络膜新生血管（choroidal neovascularization，CNV）模型的可行性。方法：BN大鼠32只一眼行氪激光（659nm）眼底光凝，另一眼作空白对照。激光功率、光凝斑直径和曝光时间分别为360mW、50μm及0．05出，分别大光凝后7，14，21,28d随机选取7只大鼠行眼底照像、荧光素眼底血管造影（FFA）检查。随机选取1只大鼠行脉络膜血管铺片检食。眼球标本行组织病理切片光镜、免疫组织化学染色观察。结果：光凝后7d，CNV开始形成，21d达到高峰，14～28d CNV无明显变化。7～21d，FFA显示造影晚期荧光素渗漏及光镜下CNV厚度逐渐增加，28d时可能因瘢痕开始形成，故FFA渗漏和CNV厚度开始减少。结论：氪激光诱导BN大鼠的CNV模型是一种较为理想的模型，FFA及CNV厚度分析是CNV定虽研究的有效手段。

多波长氪离子激光治疗糖尿病视网膜病变疗效观察

目的观察多波长氪离子激光对116例(182眼)糖尿病视网膜病变(DR)的疗效。方法根据患者病变性质、部位、分期和屈光间质情况分组,选择不同波长激光进行不同方法视网膜光凝。局部光凝组124眼,全视网膜光凝组58眼,术前均行视力、检眼镜、裂隙灯显微镜加三面镜和荧光素眼底血管造影检查,术后随访1～1.5年。结果局部光凝组病变较轻40眼,病变较重84眼,治疗1次后随访显示二者疗效有显著性差异(P<0.05)。全视网膜光凝组,其中增生前期DR26眼,光凝后有效22眼(85%)、无效4眼(15%)。增生期DR32眼,光凝后有效20眼(63%)、无效12眼(37%)。结论多波长氪离子激光是治疗DR的有效方法,依据病变情况使用不同波长扩大了治疗DR的适应证。早期进行局部光凝治疗DR可减少治疗次数和并发症。

人肺组织氪离子激光—荧光比率探测方法的研究

激光—荧光比率探测方法是近几年研究人肺组织肿瘤诊断和定位的新方法。但在临床应用中却发现比率显示的不稳定现象和很大的背景噪声容易造成肿瘤诊断的假阳性误诊。为了探讨产生这种现象的原因，我们使用氪离子激光器和比率探测设备，以提取的离体人肺组织为材料，研究在氪离子激光激发下，组织表面漫反射光和组织内部自体荧光的变化规律和背景噪声产生的原因。在此基础上，研制出采用组织绿色自体荧光代替组织表面反射光，作为参比光的比率探测方法。这种新的比率探测系统具有低的背景噪声，在临床应用中能有效地防止肿瘤诊断和定位中的假阳性误诊。

氪黄激光治疗糖尿病黄斑水肿临床研究

目的:研究氪黄激光光凝治疗糖尿病黄斑水肿的疗效。方法:对120例(150眼)糖尿病黄斑水肿患者进行氪黄激光光凝治疗。根据治疗时间距黄斑水肿发病时间,分为≤6mo及>6mo2组。同时选择同期内采用药物治疗的糖尿病黄斑水肿患者31例(42眼)作为对照组,随访12mo,观察光凝后不同时期视力及黄斑水肿的变化,进行统计学分析。结果:光凝组治疗后视力提高者89眼(59.3%),不变者58眼(38.7%),下降者3眼(2.0%),对照组治疗后视力提高者1眼(2.4%),不变者31眼(73.8%),下降者10眼(23.8%),两组间相比,均有非常显著性差异。光凝组中,≤6mo,光凝后黄斑水肿完全消退者78眼(52.0%),部分消退者66眼(44.0%),不变者6眼(4.0%),>6mo黄斑水肿完全消退者12眼(24.5%)部分消退者23眼(占50.0%),不变者14眼(28.6%)。结论:氪黄激光治疗糖尿病黄斑水肿疗效显著,可稳定和提高视力,其疗效与病程有关,早期治疗效果最佳。

氪激光光动力治疗鲜红斑痣的初步临床观察

目的 为探索真正消除鲜红斑痣病灶而不留瘢痕的治疗方法 ,采用氪激光光动力治疗鲜红斑痣进行临床观察。方法 测定光敏剂PsD 0 0 7在 30 0 70 0nm范围内的吸收曲线。随机选择 2 0例鲜红斑痣患者 ,采用自身对照方法 ,应用氪激光 413nm波长进行光动力治疗 ,观察照射即刻 ,1周至 2个月的临床变化。着重观察疗效与皮肤不良反应。志愿者激光治疗前后病理活检对比观察。结果 光敏剂PsD 0 0 7在 40 8nm有最大吸收峰。临床观察为照射区 1周出现紫癜 ,2周至 2月完全消退 ,无渗出、水泡及结痂过程。 2 0例患者均获得病灶明显消退而不留瘢痕的疗效。皮肤光度测量显示经治病灶红色指数下降。氪激光光动力治疗后 2周的组织病理表现为表皮与真皮层内大量毛细血管扩张 ,血管内皮破裂后大量红细胞外渗 ,皮肤各层结构完整 ,细胞未见异常。治疗 1月后的组织病理表现为大部分毛细血管闭锁 ,而深层血管残留。结论 氪激光光动力治疗鲜红斑痣具有破坏病灶血管但不损伤皮肤的选择性特点 ,疗效显著 。

大鼠慢性高眼压模型的建立及玻璃体游离谷氨酸变化的实验研究

目的建立大鼠慢性高眼压模型，观察不同时期的眼压变化、视神经的损伤情况和玻璃体中游离谷氨酸浓度的变化。方法Wistar大鼠30只，分为3组。用波长为532nm的氪离子黄绿激光光凝大鼠小粱网，光凝前测量一次眼压，以后每周测量眼压。在第3、6、9周分别处死1、2、3组大鼠做全视网膜铺片，1％甲苯氨蓝染色，记数平均视网膜神经元细胞密度；取20μL玻璃体用高效液相色谱分析仪测量游离谷氨酸盐浓度。结果对照眼平均眼压为（13．25±4．10）mmHg，光凝眼第1～9周平均眼压升高了1．73～2．17倍。对照眼视网膜神经元密度值为2516±196，第3、6、9周光凝眼分别为2124±108，1865±136，1654±125，差异均有统计学意义（P=0．037）；第3、6、9周光凝眼玻璃体游离谷氨酸盐浓度分别为（20．10±2．45）μmol／L，（22．35±2．75）μmol／L，（23．56±2．80）μmol／L，对照眼为（18．32±2．3）μmol／L，差异均无统计学意义（P=0．661）。结论激光光凝大鼠小梁网后，眼压中等程度升高；大鼠慢性高眼压模型的视神经损害表现为视网膜神经元密度值逐渐下降，玻璃体中游离谷氨酸盐浓度变化不明显。

康柏西普对实验性脉络膜新生血管的作用机制研究

目的探究康柏西普对实验性脉络膜新生血管(choroidal neovascularization,CNV)的作用机制。方法选取40只7周龄的雄性BN大鼠,采用多波长氪激光对豚鼠左眼行视网膜光凝,制作CNV大鼠模型,并随机分为4组,空白对照组、模型组、低剂量康柏西普组和高剂量康柏西普组;于造模后7 d、14 d注射康柏西普,并在造模后21 d进行右眼眼底彩照、眼底荧光素血管造影(fundus fluorescein angiography,FFA)检查,检测CNV发生率及渗漏面积,使用FITC灌注脉络膜铺片测量CNV面积,使用HE染色观察大鼠视网膜结构,使用Western blot检测大鼠视网膜中血管内皮生长因子(vascular endothelial growth factor,VEGF)、缺氧诱导因子-1α(hypoxia-inducible factor-1α,HIF-1α)、丝氨酸/苏氨酸激酶(serine/threonine kinase,AKT)表达情况。结果除吲哚菁绿血管造影荧光点数、CNV发生率外,相比空白对照组,模型组大鼠CNV渗透面积,荧光素渗漏面积,脉络膜结构损伤程度,视网膜中HIF-1α、AKT和VEGF蛋白的表达均显著升高,差异均有统计学意义(均为P<0.05);相比模型组,康柏西普组大鼠上述各指标显著降低,高剂量康柏西普组上述各指标显著低于低剂量康柏西普组,差异均有统计学意义(均为P<0.05)。结论康柏西普可以抑制脉络膜视网膜中HIF-1α、AKT和VEGF蛋白的表达,从而抑制由氪激光光凝眼底而产生的实验性CNV生长。

CD105评价脉络膜新生血管变化的实验研究

目的:通过免疫组织化学法观察CD105对实验性脉络膜新生血管(choroidal neovascularization,CNV)变化评价的准确性。方法:采用氪激光诱导棕色挪威(brown Norway,BN)大鼠建立实验性CNV模型。24只雄性BN大鼠,随机分为正常对照组(6只)与模型组(18只)。模型组行659nm氪激光视网膜光凝,功率360mW,曝光时间0.05s,光斑直径50μm。光凝后7、14、21d行荧光素钠和吲哚菁绿眼底血管造影,观察CNV形成率及渗漏光斑平均光密度值(average optical density,AOD)变化。处死大鼠,获得眼球标本,观察CNV的组织病理学变化和CD105因子的表达。结果:光凝后7d,CNV开始形成,14d和21d达到高峰。光凝后7、14、21d的CNV形成率分别为77.08%、85.42%、89.58%。光凝后7~21d,荧光素渗漏AOD值逐渐增高(P<0.05),7d与14d比较差异有统计学意义(P<0.05),14d与21d比较差异无统计学意义(P>0.05)。造模后7~21d,CD105因子表达先升高后下降,7d与14d比较AOD值差异有统计学变化(P<0.05),14d与21d比较AOD值差异无统计学变化(P>0.05)。结论:CD105免疫组织化学与眼底血管造影对CNV变化规律的研究结果具有高度一致性,CD105免疫组织化学评价CNV具有准确、易操作的优点。