Ablation of Vitreous Tissue with a High Repetition Rate Erbium: YAG Laser

2003 ◽  
Vol 13 (5) ◽  
pp. 424-432 ◽  
Author(s):  
M.H.J. Krause ◽  
D.J. D'Amico
Keyword(s):  
Pulse Energy ◽  
Repetition Rate ◽  
Er:Yag Laser ◽  
Nonlinear Effects ◽  
High Repetition Rate ◽  
Pulse Repetition ◽  
Careful Examination ◽  
Yag Laser ◽  
High Repetition ◽  
Pulse Energies

Purpose To quantify erbium (Er):YAG laser ablation of vitreous in relation to different pulse repetition rates ≤ 200 Hz, in order to examine the feasibility of laser for removal of vitreous gel (photovitrectomy) in clinically acceptable times. Methods Fresh porcine vitreous samples and saline controls were ablated in air with an Er:YAG laser connected to a sapphire fiber at pulse energies between 1.0 and 21.2 mJ and at pulse repetition rates between 10 and 200 Hz. Net ablation rates were determined by weight measurement. Results Reproducible and constant ablation rates were found for given laser parameters. Net ablation rates increased linearly with pulse repetition rate and nonlinearly with pulse energy. Expanded laser parameter domains permitted vitreous ablation rates as low as 1 μg/s to as high as 1031 μg/s. Ablation rates did not differ significantly between vitreous and saline. Conclusions The study documents clinically useful vitreous ablation rates that scale linearly with high repetition rates of Er:YAG laser, and suggests directions for further development of laser technology for enhanced removal of vitreous and other tissues. However, nonlinear effects of pulse energy also exist, indicating need for careful examination of ablation characteristics in various instruments.

scholarly journals Improving Signal and Photobleaching Characteristics of Temporal Focusing Microscopy with the Increase in Pulse Repetition Rate

2019 ◽  
Vol 2 (3) ◽  
pp. 65
Author(s):  
Viktoras Lisicovas ◽  
Bala Murali Krishna Mariserla ◽  
Chakradhar Sahoo ◽  
Reuben T. Harding ◽  
Michael K. L. Man ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Repetition Rate ◽  
Signal Intensity ◽  
High Repetition Rate ◽  
High Peak Power ◽  
High Pulse Energy ◽  
Two Photon ◽  
High Repetition ◽  
Laser Systems ◽  
High Pulse

Wide-field temporal focused (WF-TeFo) two-photon microscopy allows for the simultaneous imaging of a large planar area, with a potential order of magnitude enhancement in the speed of volumetric imaging. To date, low repetition rate laser sources with over half a millijoule per pulse have been required in order to provide the high peak power densities for effective two-photon excitation over the large area. However, this configuration suffers from reduced signal intensity due to the low repetition rate, saturation effects due to increased excitation fluences, as well as faster photobleaching of the fluorescence probe. In contrast, with the recent advent of high repetition rate, high pulse energy laser systems could potentially provide the advantages of high repetition rate systems that are seen in traditional two-photon microscopes, while minimizing the negatives of high fluences in WF-TeFo setups to date. Here, we use a 100 microjoule/high repetition rate (50–100 kHz) laser system to investigate the performance of a WF-TeFo two-photon microscope. While using micro-beads as a sample, we demonstrate a proportionate increase in signal intensity with repetition rate, at no added cost in photobleaching. By decreasing pulse intensity, via a corresponding increase in repetition rate to maintain fluorescence signal intensity, we find that the photobleaching rate is reduced by ~98.4%. We then image live C. elegans at a high repetition rate for 25 min. as a proof-of-principle. Lastly, we identify the steady state temperature increase as the limiting process in further increasing the repetition rate, and we estimate that repetition rate in the range between 0.5 and 5 MHz is ideal for live imaging with a simple theoretical model. With new generation low-cost fiber laser systems offering high pulse energy/high repetition rates in what is essentially a turn-key solution, we anticipate increased adoption of this microscopy technique by the neuroscience community.

High-efficiency high-repetition-rate gain-switched operation around 3  μm in Cr2+:CdSe single-crystal laser pumped by fiber-laser-pumped Ho3+:YAG laser

2019 ◽  
Vol 44 (5) ◽  
pp. 1285 ◽  
Author(s):  
Oleg L. Antipov ◽  
Ilya D. Eranov ◽  
Mikhail P. Frolov ◽  
Yuri V. Korostelin ◽  
Vladimir I. Kozlovsky ◽  
...  
Keyword(s):  
Single Crystal ◽  
Fiber Laser ◽  
Repetition Rate ◽  
High Efficiency ◽  
High Repetition Rate ◽  
Yag Laser ◽  
High Repetition ◽  
Crystal Laser

Millijoule pulse energy high repetition rate femtosecond fiber CPA system

2008 ◽  
Author(s):  
F. Roser ◽  
J. Rothhardt ◽  
T. Eidam ◽  
O. Schmidt ◽  
D.N. Schimpf ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
High Repetition

Millijoule Pulse Energy High Repetition Rate Femtosecond Fiber CPA System

2008 ◽  
Author(s):  
F. Röser ◽  
T. Eidam ◽  
J. Rothhardt ◽  
O. Schmidt ◽  
D.N. Schimpf ◽  
...  
Keyword(s):  
Pulse Energy ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
High Repetition

scholarly journals Femtosecond Laser Machining At Submicron And Nano Scale

2021 ◽  
Author(s):  
Alireza Dalili
Keyword(s):  
Femtosecond Laser ◽  
Pulse Energy ◽  
Repetition Rate ◽  
Pulse Width ◽  
Laser System ◽  
High Repetition Rate ◽  
Silicon Wafers ◽  
Good Precision ◽  
High Repetition ◽  
Nano Scale

The arrival of the femtosecond laser with a MHz repetition rate has provided the industry with a new tool to conduct submicron and nano scale machining. Several advantages such as high quality machining finish, good precision and high throughput can be obtained when using femtosecond laser to conduct nanomachining over lithography techniques currently in use. High repetition rate systems are preferred over low repetition rate femtosecond laser systems that have been studied by others due to their increased stability, speed, quality and discovery of new phenomena such as ripples and grains. This thesis proposes a high repetition rate fiber femtosecond laser system for meeting the above-mentioned conditions. The influence of the laser repetition rate and pulse energy on the size and quality of nano features fabricated on silicon wafers was investigated. Higher repetition rates led to smaller cutlines with uniform width. A 110 nm crater with a small heat affected zone of 0.79 µm was obtained at 13 MHz repetition rate and 2.042 J/cm² energy fluence. In terms of nanomachining below the ablation threshold (surface patterning), the influence of pulse width, repetition rate and pulse energy on the spacing of ripples, as well as diameter of grains created on silicon wafers, was examined. For the pulse width, repetition rate and pulse energy range used, the ripple spacing and grain diameter increased with laser pulse duration while other parameters did not play a significant role. These results show the capability of the proposed system in meeting the industry requirements.

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