Flexible Laser Research Articles

Optimal laser usage improves surgical efficiency in pediatric supraglottoplasty.

To compare patient specific and surgical efficiency outcomes in children undergoing supraglottoplasty (SGP) with flexible fiber CO2 laser in Ultrapulse mode versus cold steel at a tertiary care center. A single surgeon retrospective cohort study of pediatric patients with laryngomalacia undergoing SGP without concomitant or prior airway surgery. We reviewed perioperative complications, total hospital stay including intensive care admission, symptom resolution and the need for revision surgery. Surgical efficiency was measured as the mean total operative time and laryngeal suspension time. Among 63 patients, 32 cold steel SGPs were compared with 31 flexible fiber CO2 Ultrapulse laser SGPs. There was no statistical difference in the demographic profile. There was no statistical difference in need for intraoperative resuscitation (1 [3.0%] vs 0 [0%] cases) or perioperative intubation (4 [12.1%] vs 2 [6.3%] cases), mean total days in ICU (1.09 [0.51] vs 1.06 [0.44] [p=0.38]) or days hospitalized (1.73 [1.67] vs 1.62 [2.27] [p=0.42]), symptom resolution, need for revision surgery (2 [6.3%] vs 0 [0%] [p=0.49] patients) or mean operative time (29.0 [14.19] vs. 32.2 [22.71] [p=0.95] minutes). There was a statistically significant decreased time in laryngeal suspension in the laser group versus cold steel group (5.9 [1.80] vs 7.9 [2.19] [p=0.006] minutes). For pediatric SGPs, optimal flexible fiber CO2 laser usage can improve surgical efficiency in comparison to cold steel, with no differences in postoperative outcomes or complications. Both the flexible fiber CO2 laser and cold steel SGPs are safe and effective methods for treatment of laryngomalacia.

Outcome of Flexible Ureteroscopy and Holmium Laser Lithotripsy in the Management of Renal Stones: A two-year Retrospective Study

Abstract Background: Over the decades, the management of renal stones has shifted from the undesirably invasive open nephrolithotomy to the more effective and less invasive approaches with lower morbidity. These less invasive options include extracorporeal shock wave lithotripsy, percutaneous lithotripsy, and flexible ureterorenoscopy (fURS). Aim: This study seeks to evaluate the outcomes of flexible ureterorenoscopy with holmium: yttrium-aluminum-garnet (holmium:YAG) laser lithotripsy for the treatment of renal stones <2.0 cm in our patients. Patients and Methods: Records of 23 patients who underwent flexible ureteroscopy and holmium: YAG laser lithotripsy between October 2020 and September 2022 were reviewed retrospectively. The patients who had the flexible ureteroscopy and laser lithotripsy for renal stones <2.0 cm for various indications were the subjects of this study. All patients had computed tomographic urography preoperatively to locate the stone. Stone-free rate (SFR) was deduced from no stone detected on imaging and resolution of the patient’s preoperative complaints related to the renal stones at follow-up. Data on patients’ demographics, indication for the surgery, location of the stone, size of the stone, preoperative double J (DJ) placement, postoperative DJ stent placement, intraoperative and postoperative complications, and the SFR were retrieved and subjected to the statistical analysis. Results: A total of 23 patients had fURS and laser lithotripsy during the two-year study period. All the patients had solitary stone in the renal unit operated. The mean stone size for all the patients was 1.3 cm (range: 0.5–1.9 cm). Fifteen (65.2%) patients had DJ stent preoperatively. Postoperative DJ stent was placed in all our patients. Four (17.4%) patients had Grade 1 ureteric injury while none had high Grades (2, 3, and 4) ureteral injuries. Two (9.5%) patients had intraoperative bleeding, 1 (4.8%) had transient haematuria postoperatively while 2 (9.5%) patients had urinary tract infection. The SFR was 91.3% in a single surgery. Two patients (8.7%) had residual fragments in the lower calyx. Conclusion: Flexible ureteroscopy and laser holmium lithotripsy give a satisfactory SFR, with few complications. It is a safe and effective treatment modality for the treatment of stones <2.0 cm in the renal pelvicalyceal system.

Flexible colloidal quantum dot lasers enabled by self-assembly

Colloidal quantum dot (CQD) lasers show promising applications in flexible optoelectronic devices, due to their tunable emission wavelength, narrow spectrum bandwidth and high power intensity. However, fabricating a flexible CQD laser is challenging because of the difficulties in fabricating optical cavities on flexible substrates using traditional microfabrication technologies. Herein, we propose a one-step self-assembly approach to fabricate flexible CQD supraparticle lasers. The whole assembly approach is processed in a liquid environment without surfactants, and the formed spherical CQD supraparticles are featured with smooth surfaces, serving as high-quality-factor whispering-gallery mode cavities to support laser oscillation. A low lasing threshold of 54 µJ/cm2 is observed while exciting a CQD supraparticle with pulsed femtosecond lasers. The calculated cavity quality factor of 963 for CQD supraparticle lasers is twofold larger than that of CQD lasers assembled with surfactants. Moreover, the CQD supraparticles can serve as free-standing lasers, which allows them to be deposited on flexible substrates such as paper and cloth. Furthermore, our CQD lasers show high stability, after being continuously photoexcited above the threshold for 400 min, their lasing intensity remains at 85.7% of the initial value. As bright, free-standing and long-term stable light sources, the assembled CQD lasers proposed in this work show potential applications in wearable devices and medical diagnosis.

Electromagnetic Actuated Flexible Laser Fiber Steering Monitoring Based on Self-Sensation and Precalibration

In fiber-delivery laser surgery, both accurate actuation and sensation of flexible laser fiber is essential to achieve high precise steering control of laser system in narrow intravital operation space. This paper proposes a self-sensing method for flexible laser fiber steering monitoring based on the electromagnetic coupling actuation principle. Self-sensing of the laser fiber steering is realized by solving an inverse magnetic problem of passive magnetic source localization based on homologous actuation electromagnetic field without involving other detection technologies. To further guarantee high actuation and sensation, Kalman filter algorithm and electromagnetic actuation pre-calibration is applied. A compact proof-of-concept prototype is developed for feasibility demonstration. Systematic sensing experiments were carried out, including single-point static tracking, 1D and 2D dynamic tracking. For 2D dynamic tracking, the relative tracking error in x- and y-axis distributes in [-4.27, 4.13] % and [-3.72, 2.99] %, respectively, with mean tracking error of 0.018 mm.

Cylindrical vector beam generation from a passively mode-locked Raman fiber laser

We experimentally investigate cylindrical vector beam (CVB) generation from a passively mode-locked Raman fiber laser. The mode-locked Raman fiber lasers based on nonlinear polarization rotation (NPR), utilize the Raman gain resulted from the stimulated Raman scattering (SRS) effect in passive fibers, instead of stimulated emission amplification of active fibers in conventional mode-locked fiber lasers. With a mode-selective coupler (MSC) incorporated into the mode-locked Raman fiber laser, the generation of CVBs has been realized. In experiment, using a Raman pump source of 1454 nm, mode-locked CVB output with central wavelength of 1562 nm was obtained. The output polarization state can be switched between the radial and azimuthal polarization states, and the beam purity is above 90%. Due to the broadband Raman gain in optical fiber, the CVB output with the desired wavelength is available in principle by selecting a suitable pump source. This kind of flexible wavelength CVB Raman fiber laser may have potential applications in optical communications and fiber optics.

Properties and Applications of Random Lasers as Emerging Light Sources and Optical Sensors: A Review.

In a random laser (RL), optical feedback arises from multiple scattering instead of conventional mirrors. RLs generate a laser-like emission, and meanwhile take advantage of a simpler and more flexible laser configuration. The applicability of RLs as light sources and optical sensors has been proved. These applications have been extended to the biological field, with tissues as natural scattering materials. Herein, the current state of the RL properties and applications was reviewed.

Defining the Learning Curve of Flexible Ureterorenoscopy and Laser Lithotripsy.

To investigate the impact of learning curve (LC) on flexible ureterorenoscopy (f-URS). Patients who underwent kidney stone surgery in a urology clinic from a tertiary health care institution with f-URS were enrolled in the study. Patient characteristics, the properties of kidney and kidney stones were recorded. Also, f-URS-related parameters, hospitalization time, the success of the procedure, and complications were noted. Patients were categorized equally into 4 groups, the first 20 f-URS cases in Group 1, and the last 20 f-URS cases in Group 4. Groups were compared according to patient preoperative parameters, intraoperative outcomes, success rate and complication rate. Time from the induction of anaesthesia to insertion of flexible ureterorenoscope was 18.6 min in group 1 and 17.2 min in group 2; then it significantly decreased to 15.0 min for cases 40 through 60 and 12.4 min for cases 60 through 80 (p = 0.001). Operation time in group 3 and group 4 was significantly shorter than in group 1 and group 2 (p = 0.001). Also, fluoroscopy time was significantly longer in group 1 (82.9 seconds) and reached a plateau in group 3 (50.3 seconds) and group 4 (41.7 seconds) (p = 0.001). Additionally, after the 20th case, we achieved a significantly higher success rate in comparison to the first 20 cases (65% in group 1, 85% in group 2, 85% in group 3, and 90% in group 4, p = 0.001). Flexible ureterorenoscopy is a surgery that requires high technique and experience. The present study found that success of f-URS reached satisfactory levels after 20th cases. In addition, 40 cases may be enough for surgical proficiency regarding decreases in preparation time, operation time, and fluoroscopy time.

Safeness and efficacy of 2-µm handheld thulium laser during microsurgical resection of supratentorial and infratentorial meningiomas: Experience of a single center.

We performed a retrospective nonrandomized study to analyze the results of a microsurgery of intracranial meningiomas using 2-μm thulium flexible handheld laser fiber (Revolix jr). From February 2014 to December 2021, 75 nonconsecutive patients suffering from intracranial meningiomas, admitted in our department, have been operated on with microsurgical technique assisted by 2-μm thulium flexible handheld laser. We have reviewed demographic and clinical data to evaluate safety and efficacy of the technique. There were no complications related to the use of the 2-μm thulium laser. We operated on a high percentage of cranial base and tentorial and posterior fossa meningioma in our series. The neurological outcome and degree of resection did not differ from previous series. The neurosurgical team found the laser easy to use and practical for avoiding bleeding and traction. The use of 2-μm thulium fiber handheld flexible laser in microsurgery of intracranial meningiomas seems to be safe and to facilitate tumor resection, especially in "difficult" conditions (e.g., deep seated, highly vascularized, and hard tumors). Even if in this limited retrospective trial the good functional outcome following conventional microsurgery had not further improved, nor the surgical time was reduced by laser, focusing its use on "difficult" (large and vascularized) cases may lead to different results in the future.

A Nitrocellulose Paper-Based Multi-Well Plate for Point-of-Care ELISA.

Low-cost diagnostic tools for point-of-care immunoassays, such as the paper-based enzyme-linked immunoassay (ELISA), have become increasingly important, especially so in the recent COVID-19 pandemic. ELISA is the gold-standard antibody/antigen sensing method. This paper reports an easy-to-fabricate nitrocellulose (NC) paper plate, coupled with a desktop scanner for ELISA, which provides a higher protein immobilization efficiency than the conventional cellulose paper-based ELISA platforms. The experiments were performed using spiked samples for the direct ELISA of rabbit IgG with a limit of detection (LOD) of 1.016 μg/mL, in a measurement range of 10 ng/mL to 1 mg/mL, and for the sandwich ELISA of sperm protein (SP-10) with an LOD of 88.8 ng/mL, in a measurement range of 1 ng/mL to 100 μg/mL. The described fabrication method, based on laser-cutting, is a highly flexible one-step laser micromachining process, which enables the rapid production of low-cost NC paper-based multi-well plates with different sizes for the ELISA measurements.

Capacitive Sensing for 2-D Electrostatic MEMS Scanner in a Clinical Endomicroscope.

A flexible fiber-coupled confocal laser endomicroscope has been developed using an electrostatic micro-electromechanical system (MEMS) scanner located in at distal optics to collect in vivo images in human subjects. Long transmission lines are required that deliver drive and sense signals with limited bandwidth. Phase shifts have been observed between orthogonal X and Y scanner axes from environmental perturbations, which impede image reconstruction. Image processing algorithms used for correction depend on image content and quality, while scanner calibration in the clinic can be limited by potential patient exposure to lasers. We demonstrate a capacitive sensing method to track the motion of the electrostatically driven two-dimensional MEMS scanner and to extract phase information needed for image reconstruction. This circuit uses an amplitude modulation envelope detection method on shared drive and sensing electrodes of the scanner. Circuit parameters were optimized for performance given high scan frequencies, transmission line effects, and substantial parasitic coupling of drive signal to circuit output. Extraction of phase information further leverages nonlinear dynamics of the MEMS scanner. The sensing circuit was verified by comparing with data from a position sensing detector measurement. The phase estimation showed an accuracy of 2.18° and 0.79° in X and Y axes for motion sensing, respectively. The results indicate that the sensing circuit can be implemented with feedback control for pre-calibration of the scanner in clinical MEMS-based imaging systems.

Laser additive manufacturing of laminated bulk metallic glass composite with desired strength-ductility combination

Introducing ductile crystalline dendrites into a glassy matrix to produce bulk metallic glass composites (BMGCs) is an effective way to improve the poor ductility of bulk metallic glasses (BMGs). However, the presence of soft crystalline phases tends to decrease the strength and causes the strength-ductility tradeoff. Here, relying on the flexible laser additive manufacturing (LAM) technique that allows the composition tailoring of each layer, we successfully fabricate a lamellated Zr-based BMGC constructed by the alternating superimposition of soft and hard layers. The lamellated BMGC shows an exceptional combination of yield strength (∼1.2 GPa) and ductility (∼5%). Such enhanced strength-ductility synergy is attributed to the asynchronous deformation at two scales, i.e., inter-laminar and intra-laminar, and the unique dual-scale Ta particles that uniformly distribute on the amorphous matrix. The lamellated structure design motif, enabled by the flexible LAM technology, provides a new window for the development of high-performance BMGCs. It is also applicable to the synergistic enhancement of strength and plasticity of other brittle metallic materials.

선택적 레이저 소결을 이용한 유연인쇄전자소자 제작

It is necessary to develop a low temperature process that can deposit and pattern metal on a heat sensitive substrate because most flexible printed electronics use high temperature sensitive materials such as plastic. The most commonly used photolithography process is not suitable for flexible printed electronics because the high temperature thermal treatment process and chemicals are not compatible with plastic. Recently research has been actively conducted on a method of minimizing thermal damage to plastic and high-resolution metal patterning by using selective laser sintering after forming a liquid metal nanoparticle thin film without using existing photolithography and vacuum deposition. In this review paper, we explore flexible printed electronics such as flexible thin film transistors and flexible transparent conductors using selective laser sintering of nanomaterials and discuss future development directions.

Preface

Metal forming is a crucial and irreplaceable manufacturing technology, since it can efficiently produce components with micro-nano size, large size, complex structure and excellent performances used in the fields of aerospace, automotive, nuclear, ocean engineering, etc. Metal forming involves in the variation of geometrical shape and microstructure under the interactions of force, thermal, electric and magnetic, and the realization of coordinated control of shape and property is the widespread goal of metal forming. With the rapid development of modern society, light-weight, short process, extreme forming, green forming, and intelligent control have become the primary keywords of metal forming. Hence, developing new forming processes or innovating the traditional processes always attract the interests of scientists, academics and engineers. The International Conference on Metal Forming exactly provides a very good academic platform for the researchers throughout the world to share and communicate their latest findings in metal forming.The International Conference on Metal Forming was founded by AGH University of Science and Technology, Poland, in 1974. From 1994 to 2010, the Conference was organized every two years, jointly with University of Birmingham, UK. In 2010, University of Birmingham was replaced by Toyohashi University of Technology, Japan, and the Conference went to Japan for the first time. Metal forming 2012 was organized by AGH University of Science and Technology, together with Toyohashi University of Technology and University of Palermo, Italy. Metal forming 2014 and 2016 were respectively held by University of Palermo and AGH University of Science and Technology, whereas the Conference was organized by Toyohashi University of Technology in 2018 and came back to AGH University of Science and Technology in 2020. This year, the 19th International Conference on Metal Forming (Metal Forming 2022) was held online through a combination of live and video streaming due to the impact of global COVID-19 on September 11-14 by the China Society for Technology of Plasticity, CMES, P.R. China.The conference papers of the 19th International Conference on Metal Forming are collected in this issue. During the conference, 293 papers (including abstracts) were submitted by authors representing universities, research institutes and industry from 16 countries, and 124 papers are included in the issue of IOP Conference Series: Materials Science and Engineering. In terms of the research objects, materials such as steel, aluminium alloys and titanium alloys are still the focus, while materials such as high-temperature alloys and hard-to-deform alloys have received significantly more attention as well, and the theoretical research on material property, microstructure evolution, mechanical analysis of deformation processes and constitutive modeling have been continuously improved. In terms of forming processes, traditional forming processes such as forging, extrusion, stamping, rolling, etc. have been further developed in terms of deformation theory and process optimization, and the research on special forming technologies such as electromagnetic forming, ultrasonic vibration-assisted forming, flexible incremental forming, micro-forming, and laser forming, etc. have become more mature. With the continuous optimization and innovation of materials and forming processes, as well as the accuracy, reliability, and automation & intelligent development of forming equipment, the forming of many complex components with demanding requirements on precision, performance, and service environment has become increasingly possible.List of Steering Committee, Scientific Committee, Conference Chairs, Local Organizing Committee, Chief Editors are available in this Pdf.

Complete Stone Clearance after Retrograde Intrarenal Surgery among Patients with Urolithiasis in a Tertiary Care Centre: A Descriptive Cross-sectional Study.

Retrograde intra-renal surgery using flexible scopes and laser energy is a newer alternative in stone disease treatment armamentarium. It is claimed to be superior to other modalities for stone clearance, complications and hospital stay. The aim of this study was to find out the prevalence of complete stone clearance after retrograde intra-renal surgery among patients with urolithiasis in a tertiary care centre. This was a descriptive cross-sectional study conducted in the Department of Urology in a tertiary care centre from 15 June 2021 to 14 May 2022 including adult patients with stone size up to 15 mm. Ethical approval was obtained from the Institutional Review Committee (Reference number: IRC-PA-143/2077-78). Convenience sampling was done. The prevalence of complete stone clearance (no residual fragment >4 mm) was calculated. Point estimation and 95% confidence interval were calculated. Among 42 patients, 36 (85.71%) patients (75.1-96.3, 95% Confidence Interval) achieved complete stone clearance. The mean age was 40.26±14.05 (16-74) years and the stone size was 1.27±0.19 (0.9 -1.5) cm. Similarly, the mean operating time was 51.55±9.34 (40-85) minutes and the hospital stay was 1.33±0.52 (1-3) days. Grade 3 ureteric injury occurred in one case. Residual fragments were seen in 6 cases (14.29%). Sepsis occurred in 4 cases (11.11%). The prevalence of complete stone clearance was similar among patients undergoing retrograde intra-renal surgery in our study when compared to other studies conducted in similar settings. laser; miniaturization; postoperative complications.

Flexible Graphene-Copper Nanocomposite for Potential Wearable Electronics Applications

The demand for flexible and wearable electrochemical sensors has surged due to their low cost and portability. This study produces and characterizes low-cost and environmentally friendly flexible laser engraved graphene/Cu nanoparticles composite materials as a potential electrode for electronic applications. The electrode is fabricated by directly engraving Polyimide substrate using a CO2 laser machine to produce Laser Engraved Graphene (LEG). The electrode is then modified with copper nanoparticles via a one-step pulse electrodeposition technique to be characterized structurally, mechanically, and electrochemically using SEM, XRD, bending test, electrochemical impedance spectroscopy, and cyclic voltammetry to assess their stability and electrocatalytic activity. The laser irradiation of PI results in 3D porous graphene structure formation that increases electron transfer rate and the electrochemically active surface area. Copper deposition improves the sensitivity of LEG by its high conductivity.

Self‐Steering Lasing System Enabled by Flexible Photo‐Actuators with Sandwich Structure

AbstractWith the flourishing development of artificial intelligence, lasing with tailored features generated by photonic crystal (PhC) lasers has been playing a more important part in the optics field and in potential applications of self‐control, light detection and ranging, telecommunications, and holography imaging. As an information vehicle, the optical beam's maneuverability is influenced by the working wavelength, direction, and efficiency of the laser. Liquid crystal (LC)‐based mirrorless lasers are widely investigated in manipulating the tuning of emission wavelength. Realizing fast self‐steering of the laser beam to tune the emission direction is challenging because of the limitation on the complex and expensive inorganic fabrication and circuit design. In this work, a self‐steered lasing from a defect‐mode sandwich film composed of photomechanical deformable azobenzene cholesteric LC elastomer (CLCE) PhC layers and an isotropic gain interlayer is demonstrated. On the basis of the great light‐deformability of the CLCE, the output single‐mode lasing emission of the sandwich‐film laser can be steered quickly by UV irradiation in a wide angular tuning range of ≈±57°. This flexible, portable, and durable laser system with controllable beam‐steering and mechanical robustness is envisioned to open a gate for autonomous vehicles, self‐sustaining machines, and optical devices with the core feature of photomechanical conversion.

Time-domain flexible pulse fiber laser generation and high-power evolution based on inter-band excitation of lead sulfide nanoflakes

Ultrafast photonics has become an interdisciplinary topic of great significance owing to the spectacular development of compact and efficient ultrafast pulse generation. Saturable absorbers (SAs) are the kernel for ultrafast pulse generation. However, the conventional SAs performance is plateauing owing to the complex preparation process, the diversification of demand for pulse width, and the relatively low laser output at mill watt level. Herein, high-quality comprehensive vertical Lead Sulfide (PbS) nanoflakes were synthesized by the physical vapor deposition (PVD), and a home-build handy dry-transfer system was used to simplify the fabrication process of PbS saturable absorbers device (PbS-SAs). Total-energy calculations by the density functional theory (DFT) were performed to further understand the saturable absorption characteristic of PbS. A time-domain flexible erbium-doped fiber pulse laser has obtained Q-switched, mode-locked, and highest 14th order harmonic mode-locked pulse. Based on a selected mode-locked operation, an all-fiber master oscillator power amplifier (MOPA) pulse laser system was proposed and demonstrated. The integrated system based on PbS-SAs achieved a time-domain flexible fiber pulse laser, high order harmonic mode-locked pulse, and a picosecond pulse (∼287 ps) with high average power of ∼57.5 W and peak power of ∼13.7 kW at the central wavelength of 1562 nm. This research not only provides a simple manufacturing process for high uniformity SAs devices but also greatly improves output power, which would attract interest in exploring the unique properties of nanocomposite SAs for photonic applications.

Clinical Effect of Flexible Ureteroscope and Laparoscope in the Treatment of Parapelvic Cyst.

Objective Comparing the clinical effect of flexible ureteroscope and laparoscope in the treatment of parapelvic cyst. Method A total of 82 patients with parapelvic cyst who underwent surgical treatment in our hospital from May 2019 to May 2020 were selected. Patients were randomly divided into a control group and an observation group; the control group underwent laparoscopic parapelvic cyst topical decompression; the observation group underwent transurethral flexible ureteroscope holmium laser incision and drainage of parapelvic cyst. The intraoperative (operative time, intraoperative blood loss, and ventilation time), postoperative (time of getting out of bed, pain score, and length of hospital stay), and recurrence were compared between the two groups. Results (1) The operative time and intraoperative blood loss in the observation group were significantly better than those in the control group (P < 0.05), while the ventilation time had no significant difference (P > 0.05). (2) The pain score and length of hospital stay in the observation group were better than those in the control group (P < 0.05). There was no significant difference in the time of getting out of bed (P > 0.05). (3) There was no serious infection or bleeding in either group. The observation group had no recurrence, and the postoperative recurrence rate was 0. There were 11 cases of recurrence in the control group, and the postoperative recurrence rate was 26.83%. The postoperative recurrence rate of the observation group was significantly lower than that of the control group, with statistical significance (χ2 = 4.604, P < 0.05). Conclusion Flexible ureteroscope for the treatment of parapelvic cyst could effectively reduce the operative time, intraoperative blood loss, and pain; in addition, the postoperative recovery was fast and the recurrence is rare, which was worth popularizing.

Multi-Wavelength Spatiotemporal Mode-Locked Fiber Laser at 1.55 μm

We propose and demonstrate an effective and simple multi-wavelength spatiotemporal mode-locked (STML) laser. The laser introduces a multimode interference (MMI) effect using the core diameter mismatch of the fibers, thus enabling simultaneous mode-locking at multiple wavelengths. For the multi-wavelength mode-locking, each wavelength exists a matching pulse sequence, and different wavelengths can possess the same pulse state or different states. Meanwhile, at the dual-wavelength operation, by adjusting the polarization controllers, not only the central wavelength can be continuously adjusted from 1552.93 nm to 1572.64 nm, but also the wavelength interval can be adjusted from 2 nm to 19 nm, which benefits from the tunability of the MMI effect. Moreover, the spectral channels can be consecutively increased from 2 to 4. The obtained results provide a platform for understanding and studying the multi-wavelength STML properties. This flexible all-fiber laser has great potential for applications in the fields of optical signal processing, fiber sensing, and information coding.

Superselective renal arterial embolization in treatment for severe renal hemorrhage after flexible ureterorenoscopy and laser lithotripsy (FURSL).

Life-threatening renal hemorrhage after flexible ureterorenoscopy and laser lithotripsy (FURSL) is a rare complication. We aim to review our unit's experience with super-selective renal artery embolization as therapeutic options for such patients. From January 2015 to November 2021, total 1125 patients underwent the FURSL procedures in our unit. Patients with life-threatening renal hemorrhage were reviewed and the information of peri-operative, operative and post-operative were recorded. Of the 1125 patients who underwent FURSL procedure, two patients with life-threatening renal hemorrhage were diagnosis; the age is 67 and 42 years old, respectively. Preoperative imaging examination showed that two patients had upper ureteral stone and renal stone ranging in size from 1.2 to 3.0 cm. Female patient placed the D-J stent for two weeks before FURSL. After the operation, both patients had the massive gross hematuria, significant drop of hemoglobin (Hgb), blood pressure lowering and needed to transfusion. CT scan showed that the male patient had an intrarenal hematoma. All these two were treated by super-selective renal artery embolization and had a successful outcome. Life-threatening renal hemorrhage after FURSL is a rare and severe complication. Super-selective renal artery embolization is a safe and effective method for the treatment of patients with severe renal hemorrhage, preserving healthy renal parenchyma and renal function.