Single Shot Ablation Craters with Ultra-Short Laser Pulses: A Comparative Study

Single Shot Ablation Craters with Ultra-Short Laser Pulses: A Comparative Study D. P. Weber1, *, V. Sudesh1, H. Kerrigan2, S. R. Fairchild2, M. C. Richardson2 1Physical Sciences Department, College of Arts and Sciences, Embry-Riddle Aeronautical University. Daytona Beach, FL, 32114, USA 2Laser Plasma Laboratory, College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA *[email protected] (832) 533-1318 Laser ablation is a technique to remove material by irradiation. This work qualitatively studies the basic mechanisms of laser ablation on GaAs, Al, Ti, Cu, and ZnSe samples by two regimes: a focused 1064 nm, 14.6 mJ pulse of 8 ns duration from an Nd:YAG laser (ns regime) and a focused 800 nm, 4.2 mJ pulse of 50 fs duration from a Ti:Sapphire laser (fs regime). The materials were ablated in these two regimes to qualitatively investigate the extent of the dominating mechanisms, as seen clearly in their craters. By firing only single shots, the formations that were created remain intact. The following diagnostics were used to view the craters: a white light interferometric microscope to determine the crater topography, an optical microscope for a more general view, and a scanning electron microscope (SEM) to view the regions smaller than the resolution of the previous instruments. Significant thermo-mechanical stress in the nanosecond regime and a sub-surface boiling layer in the femtosecond regime have been identified. This investigation has concluded and is under final analysis and preparation for publication

Temperature-dependent spectroscopic properties of Tm(3+) in germanate, silica, and phosphate glasses: A comparative study

Spectroscopic properties of thulium-doped germanate, silica, and phosphate glasses were measured and compared since such glasses are of interest as materials for fiber lasers in the eye-safe wavelength region. (3)F(4) excited state fluorescence decay dynamics was investigated at temperatures from 8 to 300 K and the results revealed a strong dependence of the (3)F(4) lifetime on the host matrix. The temperature-dependent stimulated emission cross section was obtained by using the Fuchtbauer-Ladenburg technique. In phosphate glass the fluorescent lifetime is short, making this material difficult to use for 2 mu m laser purposes. Tm(3+)-doped germanate glass shows a longer lifetime than silica, a comparable value of stimulated emission cross section and some interesting temperature-independent properties

Waveguide-pumping gain guided index antiguided fiber laser

Methods, systems and devices for a waveguide pumping gain guided index antiguided fiber laser having a fiber selected for a refractive index crossover at a wavelength between a pump wavelength and a laser emission wavelength. A waveguide pumping system pumps a light having a pump wavelength into the fiber allowing a laser light to be captured by a gain guided process in the core while the pump light, propagating in the cladding is coupled to the core. The fiber selection includes selecting a fiber with a cladding material having a refractive index less than a core material refractive index for a pump wavelength and a core refractive index at the laser emission wavelength is less than the cladding refractive index at the same laser emission wavelength to allow the pump light to propagate through the cladding as a conventional wave guided fiber laser, white the laser emission is captured within the core as an index antiguided, gain guided wave

Waveguide-Pumping Gain-Guided Index Anti Guided Fiber Lasers

Methods, systems and devices for a waveguide pumping gain guided index antiguided fiber laser having a fiber selected for a refractive index crossover at a wavelength between a pump wavelength and a laser emission wavelength. A waveguide pumping system pumps a light having a pump wavelength into the fiber allowing a laser light to be captured by a gain guided process in the core while the pump light, propagating in the cladding is coupled to the core. The fiber selection includes selecting a fiber with a cladding material having a refractive index less than a core material refractive index for a pump wavelength and a core refractive index at the laser emission wavelength is less than the cladding refractive index at the same laser emission wavelength to allow the pump light to propagate through the cladding as a conventional wave guided fiber laser, while the laser emission is captured within the core as an index antiguided, gain guided wave

Modelling and Experimentally Verifying Laser Contact Printing Optical System Using Code V

One of the most upcoming advances in modern technology is the development and fabrication of flexible microelectronics, however, it can be difficult to make use of semiconductor and metal nanoparticle properties due to the limitations of many current methods used to deposit such materials onto three-dimensional substrates. Conventional methods of depositing nanoparticles require extremely high heat in order to vaporize ink carrying particles, resulting in higher cost and slower production. By using a laser to organize nano-dot arrays, one can comprise a thin, flexible semiconductor film. This process uses a liquid suspension, carrying metal nanoparticles, in the form of microdroplets. Throughout this research, there was a heavy focus on the construction of a functional model of the optical system used for laser nanoparticle contact printing. This model was built using CODE-V Optical design software. It features a 1064 nm Gaussian beam propagating through an axicon lens, followed by a collimating biconvex lens, and then reflecting off of a parabolic mirror at a 90-degree angle. The beam is then focused using a simulated microdroplet as a super-lens. The purpose of this research is to verify the simulation experimentally. In the laboratory setting, variant weight percentages of sonicated Zinc Sulfide were sintered onto glass substrates. The heat from the laser evaporated the liquid suspension surrounding the nanoparticles, resulting in a refined conductive line of metal that can be observed through a microscope. This research is still ongoing, as parameters for the liquid suspension as well as the system are still being optimized. A huge thank you to Dr.Vikas Sudesh, Dr.Aravinda Kar, Tianyi Li, Christopher Kosan, Gunjan Kulkarni, University of Central Florida, and The Office of Undergraduate Research. Key Words: Film Deposition, Laser Printing, Guassian Beam, Nanoparticles, Microdroplet, Laser Deposition, CODE-V, Axicon, Biconvex, Parabolic Mirro

Spectroscopic properties of thulium-doped crystalline materials including a novel host, La2Be2O5: a comparative study

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High Power Fiber Lasers And Applications To Manufacturing

We summarize recent developments in high power fiber laser technologies and discuss future trends, particularly in their current and future use in manufacturing technologies. We will also describe our current research programs in fiber laser development, ultra-fast and new lasers, and will mention the expectations in these areas for the new Townes Laser Institute. It will focus on new core laser technologies and their applications in medical technologies, advanced manufacturing technologies and defense applications. We will describe a program on large mode area fiber development that includes results with the new gain-guiding approach, as well as high power infra-red fiber lasers. We will review the opportunities for high power fiber lasers in various manufacturing technologies and illustrate this with applications we are pursuing in the areas of femtosecond laser applications, advanced lithographies, and mid-IR technologies. © 2008 American Institute of Physics

Volume Bragg Grating Stabilized Spectrally Narrow Tm Fiber Laser

A Tm-doped large mode area (LMA) silica fiber laser has been locked to a stable wavelength of 2053.9 nm using a volume Bragg grating (VBG). The measured spectral width of the laser output was \u3c300 pm, limited by the spectrometer resolution. Although this laser had modest output (∼5W) and slope efficiency (41%), this new approach to spectrally limiting the output of LMA fiber lasers is inherently extendable to kilowatt powers, opening up several applications including high-power pulsed fiber lasers and spectral beam combining. Performance characteristics of the laser compared to one using a dielectric mirror as a high reflector are described, and the results imply low VBG losses. © 2008 Optical Society of America

Narrow Linewidth Volume Bragg Grating Stabilized Thulium Fiber Laser

A spectrometer resolution limited 300pm linewidth is achieved in a volume Bragg grating stabilized Thulium fiber laser. Slope efficiency and output power are comparable to a similar resonator formed by a broadband high reflectivity mirror. © Optical Society of America 2008