1 / 7

Metallic Ablation Model

Metallic Ablation Model. ME 340: David Matsumura/Ryan Sydenham. Funding provided by Millennial Data, Inc. 3D model pictured above compliments of Dr. Vladimir Solovjov . Project Summary. Objective

yank
Download Presentation

Metallic Ablation Model

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Metallic Ablation Model ME 340: David Matsumura/Ryan Sydenham Funding provided by Millennial Data, Inc. 3D model pictured above compliments of Dr. Vladimir Solovjov

  2. Project Summary • Objective • Determine energy necessary to ablate volumetric regions of thin gold film on transparent polymer substrate • Develop a model to relate ablation region to emitted laser power • To secure further funding, model was required to predict, on the same order of magnitude as experimental value would suggest, the required ablation energy • Procedure • Prepare substrate by cleaning with detergent, rinsing in deionized water, and then rinsing with ethanol (Dr. Linford’s lab, Benson Bldg) • Deposit 100 nm Au thin film by means of Electron Beam Deposition (BYU Cleanroom, 10PPM) • Ablate gold with 532 nm Laser, set to energy level determined by model (Dr. Aspland’s Lab, Benson Bldg) • Measure size of ablation (Optical Microscopy Lab, Clyde Bldg.) • Evaluate Model’s prediction ability

  3. Modeling Qsource Qreflect Qabsorb • Assumptions: • Neglect Convection and Conduction (Due to 4ns time frame) • Uniform Gold Properties • Ambient Temp: 296 K Reflectivity's effect On Energy Absorption Energy Absorbed [2]: Ablation rate [1]: Where dz=ablation depth, dt=laser pulse duration, ρ=Au density, c=heat capacity of Au, ΔT=temperature change required to vaporize Au, L=heat of vaporization of Au, R=reflectivity of Au, I=laser pulse power, α=absorption coefficient Basic Energy Balance Qabsorb=Qsource-Qreflect

  4. Modeling • Model predicts required Power (I in Watts) to ablate a desired area A (m2) • Based on aforementioned models Where dz=ablation depth, dt=laser pulse duration, ρ=Au density, c=heat capacity of Au, ΔT=temperature change required to vaporize Au, L=heat of vaporization of Au, R=reflectivity of Au, I=laser pulse energy, α=absorption coefficient, A=desired ablation area

  5. Results • Measured • Based on ablation area measured with optical microscope • Predicted • Predicted laser energy required to ablate desired area

  6. Conclusion & Recommendations • Objective Achieved • Predicted value was on the same order of magnitude as the measured value • In general, heat transfer models will only be accurate within ±20% • Discrepancies • Laser power value emitted from laser based on no energy loss • In actuality, there are significant energy loses as laser energy is filtered down to desire value and directed/focus to destination • If laser energy experienced by au film is actually half of what is was intended to be the margin of error decreases to 6% (this is very likely) • Some heat conduction or convection may actually exist, probably still should be neglected • Model, applied to another test, helped to secure further funding • Reliable method of determining laser output power needs to be determined and then model should be retested

  7. Appendix • Welch Ashley J. The thermal Response of Laser Irradiated Tissue. IEEE Journal of Quantum Electronics 1984; QE-20:12:1471- 1481. • Zhang, X., S. S. Chu, J. R. Ho, and C. P. Grigoropoulos. "Excimer Laser Ablation of Thin Gold Films on a Quartz Crystal." Applied Physics a: Materials Science & Processing 64 (1997): 545-552.

More Related