Resection of Calcified Aortic Heart Leaflets In Vitro by Q-Switched 2 µm Microsecond Laser Radiation

Huang

Laser & Photonics Reviews

et al. 2019

137

Q‐switched fiber lasers are of great interest in industrial material processing, nonlinear frequency conversion, spectroscopy etc. However, passive Q‐switching possesses drawbacks of degradation and failure of the saturable absorber and the difficulty in accurate modification of the repetition rate. To overcome these issues, active Q‐switching that can normally modulate the cavity quality‐factor by an externally‐driven Q‐switcher is in high demand. Herein, an actively Q‐switched laser with antimonene‐based all‐optical modulator is devised based on the high photo‐thermal efficiency (48%) and broadband response in antimonene. It is demonstrated that this actively modulated laser represents all‐optically tunable output parameters (e.g., output repetition rate), environmental stability, and easy synchronization. It is anticipated that this actively antimonene‐based all‐optical modulator with advantages of large modulation depth, low energy consumption, and high conversion efficiency has great potential in all‐optical information processing and pulsed laser engineering.

Section: Introductionmentioning

confidence: 99%

An All‐Optical, Actively Q‐Switched Fiber Laser by an Antimonene‐Based Optical Modulator

Huang

Laser & Photonics Reviews

et al. 2019

137

“…To optimize the TAVI method and improve it to the level of a controlled surgical aortic valve replacement (sAVR), it is first necessary to remove the calcified or deformed valves before a subsequent implantation of the valved stent (14,15). The feasibility of several methods of transcatheter aortic valve resection has already been demonstrated by our group (16)(17)(18)(19).…”

Section: Original Articlementioning

confidence: 99%

Transcatheter aortic valve resection: new mechanical devices

Dai¹,

Lutter²,

Frank³

et al. 2020

J Thorac Dis

Background: To improve periprocedural outcomes of transcatheter aortic valve implantation (TAVI), transcatheter mechanical resection devices were tested for prior ablation of the aortic cusps.Methods: Three mechanical transcatheter resection devices were tested in a series of native porcine (n=30) and reassembled calcified human valves (n=54). The resection time, the resected valve area, the number of released cusps, and the degree of surrounding tissue damage were measured. Afterwards, postmortem transapical-transcatheter-resections of the aortic valve in two humans were performed.Results: In the native porcine hearts, the Aesculap II device demonstrated significantly shorter resection time compared to the R&R II and the Randstad devices (6.5±2.0 vs. 28.6±24.1 vs. 23.3±14.4 sec; P=0.001).However, it created more lesions in the surrounding tissue (P=0.002). The R&R II achieved a smaller number of resected cusps than the other two devices (2.7±0.7 vs. 1.1±0.7 vs. 2.4±0.5; P<0.001, respectively).It also resected a smaller area of the aortic valve (306.5±149.2 vs. 106.7±29.6 vs. 256.8±81.3 mm2; P=0.09) but a larger mean area of the resected fragments (110.3±41.5 vs. 160.7±29.6 vs. 111.5±43.9 mm2; P=0.01).The resection of the reassembled human valves demonstrated the same results between the devices regarding resection time (P=0.001) and resected area (P=0.016), but not fragment sizes (P=0.610). Finally, transapical-transcatheter-resection of aortic valve was performed in two cadavers.Conclusions: Transcatheter aortic valve resection is feasible with variable aortic leaflet resection times and mild risk of lesions of the surrounding tissue.

“…highly attractive for microsurgical procedures and material processing [4,5]. In particular, high-repetition-rate 2 µm pulsed lasers with high peak power are advantageous for hard tissue ablation [6,7] and can also improve the efficiency of stone fragmentation and dusting during lithotripsy [8].…”

Section: Introductionmentioning

confidence: 99%

High-energy, high-peak-power diode-pumped Q-switched Tm:YAG laser at 2.02 μm with tunable repetition rate from 100 Hz to 1000 Hz

Wu,

Du,

Wang

et al. 2024

Laser Phys.

A high-energy, high-peak-power Q-switched Tm:YAG laser at 2.02 μm with a tunable repetition rate from 100 Hz to 1000 Hz and pulse duration in the hundreds of nanoseconds is demonstrated. The high energy output was achieved by employing a thermally stable linear cavity, including two compact laser diode continuous-wave side-pumped Tm:YAG laser modules. For Q-switched operation, stable Q-switched performance from 100 Hz to 1000 Hz was realized at near-room temperature. At a repetition rate of 100 Hz, the laser delivered a maximum pulse energy of 215 mJ with a pulse duration of 124.4 ns, resulting in a peak power of up to 1.73 MW. When the repetition rate was tuned to 200 Hz, 500 Hz, and 1000 Hz, pulse energies of 212 mJ, 125.6 mJ, and 68.2 mJ were obtained, with pulse durations of 133.6 ns, 176.3 ns, and 262 ns, respectively. To the best of our knowledge, these results represent the highest single pulse energies and peak powers ever accomplished for a diode-pumped Q-switched Tm-doped 2 μm laser operating at high repetition rates exceeding 100 Hz.