Thulium laser treatment for bladder cancer

Recent innovations in thulium laser techniques have allowed application in the treatment of bladder cancer.Laser en bloc resection of bladder cancer is a transurethral procedure that may offer an alternative to the conventional transurethral resection procedure.We conducted a review of basic thulium laser physics and laser en bloc resection procedures and summarized the current clinical literature with a focus on complications and outcomes.Literature evidence suggests that thulium laser techniques including smooth incision,tissue vaporization,and en bloc resection represent feasible,safe,and effective procedures in the treatment of bladder cancer.Moreover,these techniques allow improved specimen orientation and accurate determination of invasion depth,facilitating correct diagnosis,restaging,and reevaluation of the need for a second resection.Nonetheless,large-scale multicentre studies with longer follow-up are warranted for a robust assessment.The present review is meant as a quick reference for urologists.

A Perspective of Laser Sampling for Inductively Coupled Plasma-Atomic Emission Spectro metry for Rock and Mineral Analysis

The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser sampling of liquid samples for inductively coupled plasma -atomic emission spectrometry has been proposed , and its analytical performance investigated.Experimental results showed that,as a method of sample introduction , laser vaporization of liquid samples enjoyed certain advantages , e.g.,much higher sensitivity, much lower detection limit and reduced sample volume , over solution nebulization . A perspective of the application of laser sampling-inductively coupled plasma - actomic emission spectrometry for rock and mineral analysis is estimated as well.

A Review on Fiber Lasers

After a half century of development, fiber laser has evolved from a concept to a great family penetrating into various fields of applications. This paper reviews the history and current development of fiber lasers, with topics covering both continuous wave and short pulse fiber lasers. Important issues such as the major rare earth dopants, fiber laser brightness, polarization effects, clad pumping technology, beam combination, mode locking and pulse shaping are discussed in this paper.

NUMERICAL SIMULATION OF THE TEMPERATURE FIELD IN A SOLDER BALL UNDER PULSED LASER AND ITS EFFECT ON THE VIBRATION OF THE SOLDER

The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat source. Finite element method is applied to analyzed the temperature field in the solder ball, and experi- ment is conducted to test the vibration. the results show that,that, the temperature field flucturates with the same frequency as that of the laser pulse, which in turn causes a forced vibration of the same frequency in the liquid solder ball.

Weld Defects in Laser-Welded 7A52 High-Strength Aluminum Alloy Plates with Varying Thicknesses

This study aims to explore a method suitable for welding 7A52 high-strength aluminum alloy plates with continuously varying thicknesses and the causes of microscopic defects in welds in order to improve welding quality.Comparative tests were conducted to analyze weld defects and deformation when welding the aluminum alloy plates with varying thicknesses at constant laser power.The laser power required for melting welds at varying-thickness positions was estimated.Weld defects and deformation when welding aluminum alloy plates with varying thicknesses at con-tinuous variable laser power were detected.The causes of microscopic weld defects during constant-power welding were analyzed.The welding defects and deformation and the welding quality were improved by welding aluminum alloy plates at continuous variable power.

Suppression of transmembrane sodium currents on the freshly isolated hippocampal neuron cell with continuous infrared light

Physiotherapeutic effects of infrared lasers have been proved in clinic.These infrared-based regulations of the bioelectrical activities can roughly be classied into enhancement and suppression of action potential(AP),which are described by sodium(Na)and potassium(K)transmembrane current equations,named as Hodgkin and Huxley(HH)-model.The enhancement effect is able to evoke or strengthen the AP when infrared light is applied.Its corresponding mechanism is commonly ascribed to the changes of the cell membrane capacitance,which is transiently increased in response to the infrared radiation.The distinctive feature of the suppression effect is to inhibit or reduce the AP by the designed protocols of infrared radiation.However,its mechanism presents more complexity than that in enhancement cases.HH-model describes how the Na current determines the initial phase of AP.So,the enhancement and suppression of AP can be also ascribed to the regulations of the corresponding Na currents.Here,a continuous infrared light at the wavelength of 980 nm(CIS-980)was employed to stimulate a freshly isolated hippocampal neuron in vitro and a suppression effect on the Na currents of the neuron cell was observed.Both Na and K currents,which are named as whole cell currents,were simultaneously recorded with the cell membrane capacitance current by using a patch clamp combined with infrared irradiation.The results demonstrated that the CIS-980 was able to reversibly increase the capacitance currents,completely suppressed Na currents,but little changed K currents,which forms the steady outward whole cell currents and plays a major role on the AP repolarization.A conrmation experiment was designed and carried out by synchronizing tens of milliseconds of infrared stimulation on the same kinds of hippocampal neuron cells.After the blocked K channel,a reduction of Na current amplitude was still recorded.This proved that infrared suppression of Na current was irrelevant to K channel.A membrane capacitance mediation process was preliminarily proposed to explain the Na channel suppression process.

Development and Demonstration of Australian First Working Sodium Guide Star Laser

The Australian first working sodium guide star laser system has been designed and developed for various astronomical and space-related applications. A completely diode-pumped pulsed system was developed initially followed by a largely fiber-based continuous wave (CW) system operating at 589 nm achieved through a unique wavelength conversion scheme by combining 1342 and 1050 nm through a sum frequency generation process. For the CW system, single-mode laser beams at both 1342 and 1050 nm are achieved from fiber-based seed oscillators and fiber amplifiers. The output power of ~25 W at 1342 nm is achieved from a single frequency fiber Raman amplifier. Output power up to 70 W at 1050 nm is achieved from a Yb-doped fiber pre-amplifier followed by a Yb-doped fiber power amplifier. For the sum frequency generation process, optimum focusing parameters are evaluated and determined. The CW system has generated more than 20 W output power at 589 nm, a circularly polarised beam with a good beam quality, spectral linewidth ≤ 2 MHz, and the laser output locked on the sodium D2 line at 589.159 nm. The system has been successfully demonstrated at EOS Space Research Centre, Mt Stromlo, Canberra, and become the Australian first working sodium guide star laser system.

Transurethral dividing vaporesection for the treatment of large volume benign prostatic hyperplasia using 2 micron continuous wave laser

Background The safety and efficiency of transurethral laser resection of the prostate to treat benign prostatic hyperplasia have been verified. However, this method does still not manage large volume prostates efficiently. To tackle this problem, we have designed a method of ＂transurethral dividing vaporesection of prostate＂ using a 2 micron continuous wave laser. The aim of this study was to evaluate the safety and efficiency of this method in the management of large prostates （〉80 ml）.Methods In this study, 45 cases of benign prostatic hyperplasia with a median prostatic volume of （123.7±26.7） ml （range, 80.2-159.8 ml） were treated by the same surgeon under epidural anesthesia. During the surgery, superapubic catheters were needed, and saline solution was used for irrigation. First, the prostate was divided longitudinally into several parts from the bladder neck to the prostatic apex, and then gradually incised transversely chip by chip. Intraoperative blood transfusion rate, postoperative complications, maximum urinary flow rate, International Prostate Symptom Score and quality of life scores were recorded for statistical analysis using SPSS 16.0 software.Results Intraoperatively, no transurethral resection syndrome was observed, and no blood transfusions were needed.The resected prostatic chips were easily flushed out of the bladder through the resectoscope sheath without the use of a morcellator. Median vaporesection time was （95.0±13.2） minutes （range, 75-120 minutes）, and the median retrieved and removed prostatic tissue were （25.2±5.1） g （range, 15.5-34.7 g） and （75.4±16.4） g （range, 43.8-106.1 g）, respectively. Median catheter time and hospital stay were （3.3±0.9） days （range, 3-5 days） and （4.8±1.8） days （range, 3-9 days）, respectively. After a follow-up of 6 to 12 months, two patients had stress urinary incontinence and three had anterior urethral strictures. Satisfactory improvement was seen in maximum urinary flow rate, International Prostate Symptom Score and quality of life scores.Conclusions This study showed that 2 micron laser vaporesection is a safe treatment for benign prostatic hyperplasia patients with large prostates, and the method of ＂dividing vaporesection＂ may help improve both surgical efficiency and patient outcomes.

Diode-pumped Nd:Y_xGd_(1-x)VO_4 crystal continuous-wave laser

The diode-pumped Nd:YxGd1-xVO4 crystal continuous wave (CW) laser operating at 1.06 μm with a simple plane-concave cavity and a V-shaped folded cavity for intracavity frequency-doubling have been studied. With the incident pump power of 8 W, an output power (1.06 μm) of 3.4 W was achieved, giving an optical conversion efficiency of 42.5%. 884 mW of stable green radiation was generated with the incident pump power of 5.9 W, giving an optical conversion efficiency of 15%.

Er-doped fiber ring laser gyroscopes operating in continuous waves

A direction related polarizer was inserted into a ring laser cavity to eliminate one of the two eigen-modes as well as spatial hole burning of the gain medium in a bidirectional Er-doped fiber ring laser. Thus, a fiber ring laser gyroscope （FRLG） operating in continuous wave was demonstrated. A beat signal of over 30-dB noise was observed and a good linear relation between the beat frequency shift and cavity rotation rate was obtained.

Cavity enhanced absorption spectroscopy for N_2O detection at 2.86 μm using a continuous tunable color center laser

The cavity enhanced absorption technique is applied to N2O detection around 2.86 μm using a continuous-wave color center laser. A high-finesse triangular ring cavity is used in this technology. Transmission through the cavity is obtained by jittering the cavity-length with a piezo on one of the cavity mirrors. A minimum detectable absorption coefficient of 2 × 10-6 cm-1 is achieved with a mirror reflectivity of 99.24%, corresponding to a N2O detection limit of 600 parts per billion.

Extension of continuous scanning laser Doppler vibrometry measurement for complex structures with curved surfaces

The continuous Scanning Laser Doppler Vibrometry(SLDV)developed on the base of the galvanometer scanner system has made it possible to quickly obtain the full field vibration responses within a rectangular area of the structure.In this paper,an arbitrary continuous scanning path generating method for Continuous Scanning Laser Doppler Vibometry(CSLDV)is further put forward in order to allow the CSLDV suitable for testing structures featured by complex shapes not just for regular areas.In the first step,the relationship between position of laser spot and the driving voltages of galvanometer scanner system has been described by a mathematical modeling.Then,a novel arbitrary scanning path generating strategy based on CSLDV is presented by deforming a normalization rectangular scanning path to an arbitrary continuous scanning path.The mapping relation between the normalization rectangular scanning path and arbitrary continuous scanning path is established using the reference points.In the second step,a compressor blade with curved surface was taken as an example for modal test using the proposed method.At the same time,a validated experiment was performed in SLDV.The results show the mode shapes derived from the extended CSLDV are in agreement with those from SLDV and the Modal Assurance Criterion(MAC)between the two are all greater than 0.96.They also demonstrate the feasibility and effectiveness of the proposed method for CSLDV test and show strong potential on further practical engineering applications.

All-solid-state quasi-continuous-wave high power dispersion cavity tunable Ti:sapphire laser

An all-solid-state quasi-continuous-wave dispersion cavity tunable Ti：sapphire laser pumped by a laser diode pumped frequency-doubled Nd：YAG laser is reported. Using a dense flint glass prism as the dispersion element, a tuning range from 730 to 880 nm with the tinewidth of 3 nm and the pulse width of 17.2 ns was obtained. The maximum output power of this laser system was 5.6 W at 786.3 nm corresponding to an optical-to-optical conversion efficiency of 25.5% under the pump power of 22 W.

Secondary Austenite Morphologies in Fusion Zone of Welded Joint after Postweld Heat Treatment with a Continuous Wave Laser

In order to improve the weldability of duplex stainless steels,obtaining more secondary austenite in the weld metal is an effective way.Therefore,optimizing the secondary austenite by changing its morphology,volume fraction and stability may be expected to enhance the ductility of the weld.The secondary austenite morphologies in the fusion zone of the laser continuously heat treated welds of 2205 duplex stainless steel were investigated.The secondary austenite morphologies were found to be influenced by different laser power level.The secondary austenite with penniform,freely grown and dendritic shape appeared in the course of 4,6 and 8 kW continuous heat treatment,respectively.It was found that there were three kinds of morphologies of secondary austenite in the fusion zone treated by different power,i.e.,widmannst¨atten austenite,grain boundary austenite and intragranular austenite.The results demonstrated that the mechanism of the secondary austenite formation was a displacement mechanism during the initial austenite lath formation and a diffusion mechanism during cooling.The nitrides provided the nitrogen for the transformation and at the same time acted as nucleation sites for the secondary austenite.

Highly efficient continuous-wave laser operation of laser diode-pumped Nd,Y:CaF_2 crystals

The effect of co-doping Y3＋ and the doping concentration of Nd3＋ on the spectroscopic properties and laser performance of Nd：CaF2 crystals are investigated systematically. For a 0.5% Nd：CaF2 crystal, the emission life- time at 1.06 μm increases from 18 to 361 μs by co-doping 10 at.% Y3＋, while the emission cross section increases to 4.27 × 10^-20 cm2 at 1054 nm. With a 10 at.% doping concentration of Y3＋, Nd, Y：CaF2 crystals concentrate emission bands that peak at 1054 nm with shoulders at 1063 nm, and FWHM at about 30 nm. A diode-pumped, highly efficient laser operation is obtained with 0.5% Nd, 1070 Y：CaF2 and 0.6% Nd, 1070 Y：CaF2 crystals, with slope efficiencies over 30% and 27%, respectively, and a maximum output power up to 901 mW.

Superresolution imaging of DNA tetrahedral nanostructures in cells by STED method with continuous wave lasers

DNA tetrahedral nanostructures are considered to be uew nanocarriers because they can be precisely controlled and hold excellent penetration ability to the cellular membrane. Although the DNA tetrahedral nanostructure is extensively studied in biology and medicine, its behavior in the cells with nanoscale resolution is not understood clearly. In this letter, we demonstrate superrcsolution fluorescence imaging of the distribution of DNA tetrahedral nanostructures in the cell with a simulated emission depletion （STED） microscope, which is built based on a conventional eonfocal microscope and can t）rovide a resolution of 70 nm.

Quadratic nonlinear response to 1.56-μm continuous wave laser in semi-insulating GaAs

The nonlinear photoresponse to a 1.56μm infrared continuous wave laser in semi-insulating （SI） galliu- marsenide （GaAs） is examined. The double-frequency absorption （DFA） is responsible for the nonlinear photoresponse based on the quadratic dependence of the photocurrent separately on the coupled optical power and bias voltage. The electric field-induced DFA remarkably affects the native DFA in SI GaAs. The surface electric field or the surface band-bending of SI GaAs significantly affects the magnitude variation of the Dhotocurrent and dark current

2277-W continuous-wave diode-pumped heat capacity laser

A high power continuous-wave （CW） diode-pumped Nd：YAG laser operated in heat capacity mode is demonstrated by use of two identical highly efficient diode-pumped laser heads placed in a plane-plane resonator. The laser heads are uniformly pumped with a five-fold symmetrical side-pumping configuration, and each head is able to output maximum output power of 2200 W at 808 nm. Under a total pump power of 4290 W, the output power of the laser at 1064 nm is up to 2277 W, corresponding to an optical-to-optical efficiency of 53.1%.

Room temperature continuous wave operation of 1.33-um InAs/GaAs quantum dot laser with high output power

Continuous wave operation of a semiconductor laser diode based on five stacks of InAs quantum dots （QDs） embedded within strained InGaAs quantum wells as an active region is demonstrated. At room temperature, 355-mW output power at ground state of 1.33-1.35 μm for a 20-μm ridge-waveguide laser without facet coating is achieved. By optimizing the molecular beam epitaxy （MBE） growth conditions, the QD density per layer is raised to 4 × 10^10 cm^-2. The laser keeps lasing at ground state until the temperature reaches 65 ℃.

High-power high-brightness 2-μm continuous wave laser with a double-end diffusion-bonded Tm, Ho:YVO_4 crystal

This letter demonstrates an efficient high-power high-brightness 2-μm continuous-wave （CW） laser with double-end, diffusion-bonded Tm, Ho：YVO4 crystal cooled with liquid N2. The reduction in thermal stress in the composite Tm, Ho：YVO4 rod enabled the laser to achieve a laser output power of 23.4 W at 2.05 μm, which is 1.37 times higher than that of the non-composite Tm, Ho：YVO4 rod. The corresponding slope efficiency is 37.3% and the optical optical conversion efficiency is 35.4%. The beam quality M2 factor is about 1.85 at 20 W output level with circularly symmetric beam spot.