An in vitro study on focusing fs-laser pulses into ocular media for ophthalmic surgery

Merker, Marina; Ackermann, Roland; Kammel, Robert; Kunert, Kathleen S.; Nolte, Stefan

doi:10.1002/lsm.22179

Cited by 11 publications

(7 citation statements)

References 35 publications

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“…14 To overcome these undesired side effects, varying the pulse duration along the direction of propagation by simultaneous spatial and temporal focusing (SSTF) is a promising approach. 24,25 In this concept, the spectral components of the incident ultrashort laser pulse are spatially separated, resulting in a rainbow-like collimated beam, while reducing the local bandwidth within this beam leads to an increased pulse duration.…”

Section: Introductionmentioning

confidence: 99%

Enhancing precision in fs-laser material processing by simultaneous spatial and temporal focusing

et al. 2014

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In recent years, femtosecond (fs)-lasers have evolved into a versatile tool for high precision micromachining of transparent materials because nonlinear absorption in the focus can result in refractive index modifications or material disruptions. However, when high pulse energies or low numerical apertures are required, nonlinear side effects such as self-focusing, filamentation or white light generation can decrease the modification quality. In this paper, we apply simultaneous spatial and temporal focusing (SSTF) to overcome these limitations. The main advantage of SSTF is that the ultrashort pulse is only formed at the focal plane, thereby confining the intensity distribution strongly to the focal volume and suppressing detrimental nonlinear side effects. Thus, we investigate the optical breakdown within a water cell by pump-probe shadowgraphy, comparing conventional focusing and SSTF under equivalent focusing conditions. The plasma formation is well confined for low pulse energies ,2 mJ, but higher pulse energies lead to the filamentation and break-up of the disruptions for conventional focusing, thereby decreasing the modification quality. In contrast, plasma induced by SSTF stays well confined to the focal plane, even for high pulse energies up to 8 mJ, preventing extended filaments, side branches or break-up of the disruptions. Furthermore, while conventional focusing leads to broadband supercontinuum generation, only marginal spectral broadening is observed using SSTF. These experimental findings are in excellent agreement with numerical simulations of the nonlinear pulse propagation and interaction processes. Therefore, SSTF appears to be a powerful tool to control the processing of transparent materials, e.g., for precise ophthalmic fs-surgery.

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Section: Introductionmentioning

confidence: 99%

Enhancing precision in fs-laser material processing by simultaneous spatial and temporal focusing

et al. 2014

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“…The fiber laser parameters and burst-mode operation explored in this work appear to be well-suited to a variety of medical applications including neurosurgery and ophthalmology 7,9,28 . Applications of the present laser system to femtosecond cataract surgery is currently underway in our laboratory; preliminary results indicate that the required pulse energy is reduced for the burst mode, which is expected to reduce complications 15,29,30 . While the laser system is capable of generating 8-µJ, 300-fs pulses in both regimes, high-rate and non-thermal ablation could be achieved with pulse energies as low as 3 µJ in the burst mode operation.…”

Section: Discussionmentioning

confidence: 99%

Efficient, high-speed ablation of soft tissue with few-microjoule, femtosecond pulse bursts

Kerse,

Yavas,

Kalaycıoğlu

et al. 2014

Preprint

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Femtosecond pulses hold great promise for high-precision tissue removal. However, ablation rates are severely limited by the need to keep average laser power low to avoid collateral damage due to heat accumulation. Furthermore, previously reported pulse energies preclude delivery in flexible fibers, hindering in vivo operation. Both of these problems can be addressed through use of groups of high-repetition-rate pulses, or bursts. Here, we report a novel fiber laser and demonstrate ultrafast burst-mode ablation of brain tissue at rates approaching 1 mm 3 /min, an order of magnitude improvement over previous reports. Burst mode operation is shown to be superior in terms of energy required and avoidance of thermal effects, compared to uniform repetition rates. These results can pave the way to in vivo operation at medically relevant speeds, delivered via flexible fibers to surgically hard-to-reach targets, or with simultaneous magnetic resonance imaging.

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“…Passively Q-switched fiber lasers (QSFL), which are generated by Q-factor modulation or intracavity loss regulation, have attracted much attention because of their intrinsic advantages of high energy, alignment-free structure, compactness, and high stability [1][2][3][4]. Up to now, QSFLs have been widely applied in medicine, industrial material processing, fiber-optical sensing, and optical communication [5][6][7][8][9][10][11][12][13][14][15][16]; but they can also be used as an ideal platform for investigating the dynamic evolution of solitons and saturated absorption of nanomaterials [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Yttrium oxide as a Q-switcher for the near-infrared erbium-doped fiber laser

Liu

et al. 2020

Nanophotonics

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Yttrium oxide (Y 2 O 3 ) has been widely used in metal-reinforced composites, microelectronics, waveguide lasers, and high-temperature protective coatings because of its good physical and photoelectric properties. However, few studies have been done on the nonlinear optical applications of Y 2 O 3 as saturable absorbers (SAs) in fiber lasers so far. Here, a passively Q-switched nearinfrared fiber laser using Y 2 O 3 as a Q-switching device is demonstrated. The optical nonlinear properties of the Y 2 O 3 SA prepared by the magnetron sputtering method were measured by the twin-detector measurement technique, and the modulation depth of the proposed Y 2 O 3 SA was found to be 46.43%. The achieved Q-switched laser delivers an average output power of 26 mW at 1530 nm with a pulse duration of 592.7 ns. To the best of our knowledge, this is the first report on the optical nonlinearity of Y 2 O 3 as a Q-switcher for the near-infrared fiber laser, which may deepen the understanding of the optical nonlinear properties of Y 2 O 3 and make inroads into the potential market of optical modulation and optoelectronic devices.

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An in vitro study on focusing fs-laser pulses into ocular media for ophthalmic surgery

Abstract: Bubble size control by laser bursts may reduce optical side-effects of fs-laser treatment. Furthermore, fs-laser treatment could be used for vitreoretinal applications.

Cited by 11 publications

References 35 publications

Enhancing precision in fs-laser material processing by simultaneous spatial and temporal focusing

Enhancing precision in fs-laser material processing by simultaneous spatial and temporal focusing

Efficient, high-speed ablation of soft tissue with few-microjoule, femtosecond pulse bursts

Yttrium oxide as a Q-switcher for the near-infrared erbium-doped fiber laser

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