In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND No studies have yet been conducted on changes in microcirculatory hemody-namics of colorectal adenomas in vivo under endoscopy.The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging(BLI),thus providing a new insight into the microcirculation of early colon tumors.AIM To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters.METHODS From October 2019 to January 2020,11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI.Video images were recorded and processed with Adobe Premiere,Adobe Photoshop and Image-pro Plus software.Four microcirculation parameters:Microcirculation vessel density(MVD),mean vessel width(MVW)with width standard deviation(WSD),and blood flow velocity(BFV),were calculated for adenomas and the surrounding normal mucosa.RESULTS A total of 16 adenomas were identified.Compared with the normal surrounding mucosa,the superficial vessel density in the adenomas was decreased(MVD:0.95±0.18 vs 1.17±0.28μm/μm2,P<0.05).MVW(5.11±1.19 vs 4.16±0.76μm,P<0.05)and WSD(11.94±3.44 vs 9.04±3.74,P<0.05)were both increased.BFV slowed in the adenomas(709.74±213.28 vs 1256.51±383.31μm/s,P<0.05).CONCLUSION The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation.Superficial vessel density was decreased,more irregular,with slower blood flow.

GaN-based blue laser diode with 6.0 W of output power under continuous-wave operation at room temperature

In this work,we reported the room-temperature continuous-wave operation of 6.0 W GaN-based blue laser diode(LD),and its stimulated emission wavelength is around 442 nm.The GaN-based high power blue LD is grown on a c-plane GaN substrate by metal organic chemical vapor deposition(MOCVD),and the width and length of the ridge waveguide structure are 30 and 1200μm,respectively.The threshold current is about 400 mA,and corresponding threshold current density is 1.1 kA/cm2.

Effect of Droop Phenomenon in InGaN/GaN Blue Laser Diodes on Threshold Current

Electroluminescence （EL） and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes （LDs） before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.

Short Pulse Width and High Peak Power 457 nm Deep Blue Laser with V-Type Cavity

An intracavity frequency doubling acousto-optically Q-switched Neodymium-doped Yttrium Orthvanadate (Nd:YVO4) 457 nm blue laser by employing a three-mirror folded cavity was demonstrated. With the incident pump power of 40.4 W, the maximum average output power of 439 mW 457 nm laser, and the minimum pulse duration of 86.14 ns and the maximum peak power of 510 W were achieved at 10 kHz. The M2 factors are 1.23 and 1.61 in X and Y directions, respectively. The power stability in two hours is better than 2%.

Infrared Laser Pumped Green and Blue Laser Emissions from a Single Solid State Material Doped by Rare Earth Ions

The possible ways and progress of infrared or red laser pumped green and blue laser emissions from a single solid state material doped by rare earth ions are outlined. The green and blue lasers realized from infrared laser pumped rare earth doped nonlinear laser crystals by means of self frequency conversion and from infrared laser pumped rare earth doped bulk, fiber and microsphere materials by means of frequency upconversion are introduced in detail. Other kinds of devices and methods are also compared. The typical nonlinear laser crystals such as YAl 3(BO 3) 4, GdAl 3(BO 3) 4, YCa 4O(BO 3) 3 , GdCa 4O(BO 3) 3, and the typical upconversion fluoride fibers are compared and analyzed. The major problems remaining to be solved and the developing trends in the area are also discussed.

20.231 Gbit/s tricolor red/green/blue laser diode based bidirectional signal remodulation visible-light communication system

We propose and experimentally demonstrate a recorded 1-m bidirectional 20.231-Gbit/s tricolor R/G/B laser diode(LD) based visible-light communication(VLC) system supporting signal remodulation. In the signal remodulation system, an LD source is not needed at the client side. The client reuses the downstream signal sent from the central office(CO) and remodulates it to produce the upstream signal. As the LD sources are located at the CO, the laser wavelength and temperature managements at the cost-sensitive client side are not needed.This is the first demonstration, to our knowledge, of a >20 Gbit∕s data rate tricolor R/G/B VLC signal transmission supporting upstream remodulation.

Low-pump sum frequency generation of frequency- stabilized 453 nm blue laser for photonic quantum interface

Generation of a cavity-enhanced nondegenerate narrow-band photon pair source is a potential way to realize a perfect photonic quantum interface for a hybrid quantum network. However, to ensure the high quality of the photon source, the pump laser for the narrow-band photon source should be generated in a special way. Here, we experimentally generate the blue 453 nm laser with a sum frequency generation process in a periodically poled lithium niobate waveguide. A 13 mW laser at 453 nm can be achieved with a low-power 880 nm laser and 935 nm laser input, and the internal conversion efficiency is 21.6% after calculation. The frequency of a 453 nm laser is stabilized by locking two pump lasers on one ultrastable optical cavity. The single pass process without employ- ing cavity enhancement can ensure a good robustness of the whole system.

Room-temperature continuous-wave operation of GaN-based blue-violet laser diodes with a lifetime longer than 1000h

GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of a blue-violet LD are investigated under direct-current injection at room temperature(25 °C). The stimulated emission wavelength and peak optical power of the LD are around 413 nm and over 600 mW, respectively.In addition, the threshold current density and voltage are as small as 1.46 kA/cm^2 and 4.1 V, respectively. Moreover, the lifetime is longer than 1000 hours under room-temperature continuous-wave operation.

Design of NO2 photoacoustic sensor with high reflective mirror based on low power blue diode laser

An NO2 photoacoustic sensor system with a high reflective mirror based on a low power blue diode laser is developed in this work. The excitation power is enhanced by increasing the number of reflections. Comparing with a traditional photoacoustic system, the pool constant is improved from 300.24(Pa·cm)/W to 1450.64(Pa·cm)/W, and the signal sensitivity of the photoacoustic sensor is increased from 0.016 μV/ppb to 0.2562 μV/ppb. The characteristics of temperature and humidity of the new photoacoustic sensor are also obtained, and the algorithm is adjusted to provide a quantitative response and drift of the resonance frequency. The results of this research provide a new method and concept for further developing the NO2 photoacoustic sensors.

A 420nm Blue Diode Laser for the Potential Rubidium Optical Frequency Standard

We report a 42Ohm external cavity diode laser with an interference filter （IF） of 0.5am narrow-bandwidth and 79% high transmission, which is first used for Rb optical frequency standard. The IF and the cat-eye reflector are used for selecting wavelength and light feedback, respectively. The measured laser linewidth is 24 kHz when the diode laser is free running. Using this narrow-linewidth IF blue diode laser, we realize a compact Rb optical frequency standard without a complicated PDH system. The preliminary stability of the Rb optical frequency standard is 2 × 10^-13 at I s and decreases to 1.9 ×10^-14 at 1000s. The narrow-linewidth characteristic makes the IF blue diode laser a well suited candidate for the compact Rb optical frequency standard.

The Photopolymerization Kinetics of Acryl amide Sensitized with Toluidine Blue-Alcoholamine Induced by He-Ne Laser

Toluidine blue(TB) is a good sensitizer for the polymerization of acrylnmide(AM) induced by He-Ne laser. With TB as a sensitizer and various alcoholamine as donors, the photoredox of TB and the polymerization kinetics of AM induced by He-Ne laser were investigated. It was found that either for the photoredox of TB or for the polymerization of AM, the activity of alcoholamine increases in the order of EOA<DEOA <TEOA in TB-alcoholamine sensitized system. The overall apparent kinetic equations of AM polymerization at 30℃ have been determined. In addition, the molecular weights under various conditions was measured.

450 nm diode laser:A new help in oral surgery

AIM To describe the performance of 450 nm diode laser in oral surgery procedures.METHODS The case described consisted of the removal of a lower lip fibroma through a blue diode laser(λ = 450 nm). RESULTS The efficacy of this device, even at very low power(1W, CW), allows us to obtain very high intra and postoperative comfort for the patient, even with just topical anaesthesia and without needing suture. The healing process was completed in one week and, during the follow-up, the patient did not report any problems, pain or discomfort even without the consumption of any kind of drugs, such as painkillers and antibiotics. The histological examination performed by the pathologist showed a large area of fibrous connective tissue with some portions of epithelium-connective detachments and a regular incision with very scanty areas of carbonization.CONCLUSION The 450 nm diode laser proved of being very efficient in the oral soft tissue surgical procedures, with no side effects for the patients.

超声内镜结合LCI/BLI-ME判断根除幽门螺杆菌后早期胃癌浸润深度的研究

目的 探讨超声内镜结合联动成像技术/蓝激光成像技术-放大内镜(LCI/BLI-ME)对根除幽门螺杆菌后早期胃癌浸润深度的判断及其准确性的影响因素,评价其临床应用价值。方法 收集2017年10月至2023年6月武汉市第一医院收治的91例根除幽门螺杆菌后早期胃癌患者的临床资料,以病理学检查结果作为判断标准,总结根除幽门螺杆菌后胃黏膜及早期胃癌在内镜下的特征表现,分析超声内镜结合LCI/BLI-ME对根除幽门螺杆菌后早期胃癌浸润深度的判断准确性及影响其判断准确性的相关因素。诊断效能的统计学描述采用灵敏度、特异度、准确度表示;采用χ^(2)检验和多因素Logistic回归分析对超声内镜的诊断结果与术后病理学检查结果进行比较。结果 超声内镜结合LCI/BLI-ME对根除幽门螺杆菌后早期胃癌浸润深度判断的总体准确率77.08%,对uT1a期及uT1b期的判断准确率分别为82.86%和61.53%。分期不足12例,占17.14%;分期过度10例,占38.46%。对黏膜层病变判断的诊断敏感度85.29%,诊断特异度57.14%,阳性预测值82.86%,阴性预测值61.5%。单因素和多因素Logistic回归分析结果表明,病变最大径、组织分化类型是影响判断准确性的因素,而病变部位、病灶形态与判断准确性无相关性。病灶越大,对浸润深度判断的准确性越低;组织分化程度越低,对浸润深度判断的准确性越低。结论 超声内镜结合LCI/BLI-ME对根除幽门螺杆菌后早期胃癌uT1a期的浸润深度判断具有较好的临床应用价值,病灶大小及组织分化程度对判断的准确性有影响。

Spectral dynamical behavior in two-section, quantum well,mode-locked laser at 1.064 μm

In this study, two-section mode-locked semiconductor lasers with different numbers of quantum wells and different types of waveguide structures are made. Their ultrashort pulse features are presented. The spectral dynamical behaviors in these lasers are studied in detail. In the simulation part, a two-band compressive-strained quantum well（QW） model is used to study thermally induced band-edge detuning in the amplifier and saturable absorber（SA）. A sudden blue shift in laser spectrum is expected by calculating the peak of the net gain. In the experiment part, the sudden blue shift in the emission spectrum is observed in triple QW samples under certain operating conditions but remains absent in single QW samples.Experimental results reveal that blue shift phenomenon is connected with the difference between currents in two sections.Additionally, a threshold current ratio for blue-shift is also demonstrated.

Third Order Optical Nonlinearities and Spectral Characteristics of Methylene Blue

We have investigated third order nonlinear optical properties and spectral characteristics of methylene blue dye in both polymer and liquid mixtures. The spectral characteristics of the dye is studied by recording the absorption and fluorescence spectra of the dye doped in poly(methylmethacrylate) modified with additive n-butyl acetate(nBA) and the dye in MMA and nBA (liquid mixture). The spectral results of the dye doped polymer rod are compared with dye in liquid Mixture. The nonlinear measurements of the dye in liquid and polymer medium were performed using CW He-Ne laser of wavelength 632.8 nm by employing z-scan technique. The dye methylene blue showed a negative nonlinear refractive index.

区级医院开展经尿道450 nm蓝激光前列腺汽化术的初步报道

目的初步探讨在区级医院开展经尿道450 nm蓝激光前列腺汽化术治疗良性前列腺增生(BPH)的临床效果,为区级医院BPH治疗方法的选择提供参考。方法回顾性分析2023年1月—9月在西安市长安区医院泌尿外科接受手术治疗的39例BPH患者的临床资料。根据手术方式分为两组,其中蓝激光组(n=19)行经尿道450 nm蓝激光前列腺汽化术,电切组(n=20)行经尿道前列腺电切术(TURP)。比较两组患者的手术时间、血红蛋白下降值、术后膀胱冲洗时间、术后留置尿管时间及并发症发生情况。结果所有患者的手术均顺利完成。两组的手术时间[(45.11±22.08)min vs.(81.25±29.37)min]、术后膀胱冲洗时间[(34.05±9.41)h vs.(47.60±9.05)h]及血红蛋白下降值[(7.79±5.86)g/L vs.(16.40±10.23)g/L]比较,蓝激光组明显低于电切组(P<0.05)。蓝激光组术后尿潴留1例,两组术后留置尿管时间差异无统计学意义(P>0.05)。结论采用450 nm蓝激光前列腺汽化术治疗BPH具有出血量少、手术时间短及术后膀胱冲洗时间少的特点,值得在基层医院推广应用。

基于合束的500 W蓝光半导体激光模块化研究

为了满足新能源汽车电池制造、航空航天高反射材料铜的焊接和金属3-D打印领域的应用需求,采用空间合束以及偏振合束方法,研制出基于150 W阵列式蓝光单元的500 W蓝光半导体激光模块。实现了快轴上发光单元内部的光束叠加、慢轴上多个发光单元交叉加密输出,消除发光死区,将4个独立发光单元的激光合束为一个方形光斑,增加功率密度而不影响光束质量;并研究了激光模块热效应与冷却特性,设计出激光模块稳定输出方案。结果表明,最终输出蓝光激光快轴发散角0.4°,慢轴发散角0.02°,发光功率501 W,整体效率81.3%,功率波动小于0.7%。本研究成果为进一步研制4 kW大功率蓝光半导体激光器提供了基本合束模块。

Diode-pumped Kerr-lens mode-locked Ti: sapphire laser with broad wavelength tunability

We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.

经尿道蓝激光前列腺切开术治疗小体积良性前列腺增生的临床疗效

目的分析经尿道蓝激光前列腺切开术(BLTUIP)治疗小体积(≤30 mL)良性前列腺增生(BPH)的临床效果与可行性。方法回顾性分析2023年3—10月新疆医科大学第一附属医院泌尿中心接受BLTUIP治疗的34例BPH患者的临床资料。记录患者的手术时间、450 nm蓝激光出光时间、980 nm红激光出光时间、术后膀胱冲洗时间等。比较患者术前、术后3及6个月的国际前列腺症状评分(IPSS)、生活质量评定量表评分(QoL)、最大尿流率(Qmax)、残余尿量(PVR)、国际勃起功能指数(IIEF-5)、射精情况及术后并发症发生率。结果34例患者均顺利完成手术,无术中转开放或转经尿道前列腺电切术(TURP)治疗者。手术时间12.7(10.8,14.3)min,450 nm蓝激光出光时间11.7(9.6,13.3)min,980 nm红激光出光时间1.0(1.0,2.0)min,术后膀胱冲洗时间5.0(2.8,8.0)h,总住院时间6.0(4.0,7.0)d,术后住院时间2.0(2.0,3.0)d,术后尿管留置时间2.0(0,2.0)d。术后随访3及6个月,患者的IPSS、QoL及PVR均较术前明显降低,Qmax较术前明显增大,差异均有统计学意义(P<0.001),但IIEF-5评分与术前比较差异无统计学意义(P>0.05)。随访发现,术后3个月内,有4例患者(11.8%)发热;术后3~6个月内,有1例(2.9%)尿道外口狭窄。术前有性生活史的8例患者中,术后有1例(12.5%)发生逆行射精,所有患者术后随访过程中均未发生血尿。结论BLTUIP治疗体积≤30 mL的BPH,可缩短手术时间、减少术后并发症发生率、改善患者生活质量,是一种新型、安全、高效的手术方法。

高转换效率腔内倍频外腔面发射蓝光激光器

高功率高光束质量的蓝色激光在激光显示与照明、水下通信和成像、有色金属加工等许多领域具有广泛应用前景.本文利用增益芯片底部的高反镜分布布拉格反射镜、折叠镜以及后端反射镜构成V型谐振腔,通过腔内插入非线性晶体LBO,获得了高转换效率的高功率、高光束质量蓝光输出.实验研究了非线性晶体的长度、基频激光的线宽、倍频走离角的补偿等不同因素对外腔面发射激光器腔内倍频蓝光输出功率的影响.在LBO的Ⅰ类相位匹配条件下,当晶体长度为5 mm,所用双折射滤波片厚度为1 mm时,获得超过6 W的491 nm波长蓝光输出,x和y方向的光束质量M2因子均为1.08,倍频转换效率为63%.