1 / 51

Engineering Society

Engineering Society. Explore Discover Be Inspired. Session 02. Lasers. Darin Madzharov , Borislav Hadzhiev, Andrey Raykov, Farooq Aslam, David Kronmueller. Session 02 ~ 01/12/14. Engineering Society LASERS. Overview. Theory & Technology Surgical Application

bruce-bean
Download Presentation

Engineering Society

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. Engineering Society Explore Discover Be Inspired Session 02 Lasers Darin Madzharov, Borislav Hadzhiev, Andrey Raykov, Farooq Aslam, David Kronmueller Session 02 ~ 01/12/14

  2. Engineering Society LASERS Overview • Theory & Technology • Surgical Application • Laser Vision Correction • Laser Printers • Q&A Session Session 02 ~ 01/12/14

  3. Engineering Society LASERS Section 1 Theory & Technology Session 02 ~ 01/12/14

  4. Engineering Society LASERS Principles of Operation • Resonator-gain medium based lasers • Three main aspects: • Photon emission • Power pumping • Gain resonator • Free electron lasers Session 02 ~ 01/12/14

  5. Engineering Society LASERS Principles of Operation • Photon Emission • Discrete energy levels in atoms • During transition between levels a photon is tttreleased • Emitted wavelength dependent on the tttseparation of the energy states • Different media Session 02 ~ 01/12/14

  6. Engineering Society LASERS Principles of Operation • Photon Emission Session 02 ~ 01/12/14

  7. Engineering Society LASERS Principles of Operation • Power Pumping • Population inversion is needed • Constant input of energy required during lasing • Different energy sources are used – optical tttpower pumps, electric discharge and electron tttbeams, chemical “combustion engines”, etc. Session 02 ~ 01/12/14

  8. Engineering Society LASERS Principles of Operation • Resonator • Confines light within the excitable medium, thus tttassuring stimulated emission Session 02 ~ 01/12/14

  9. Engineering Society LASERS Principles of Operation • Modes of Operation • Continuous • Pulsed • Q-switching • Modelocking Session 02 ~ 01/12/14

  10. Engineering Society LASERS Principles of Operation • Intensity Distribution Session 02 ~ 01/12/14

  11. Engineering Society LASERS Types of Lasers • Gas Lasers • Applications • Educational purposes – HeNe • Cutting and welding – High Power CO2 • Source of UV light – TED • Deep UV light generation – Metal Ion Session 02 ~ 01/12/14

  12. Engineering Society LASERS Types of Lasers • Gas Lasers • Chemical Lasers (chemical combustion) • “Combustion chamber” • Ethylene burns in NF3 to generate flourine tttttradicals • React with hydrogen Session 02 ~ 01/12/14

  13. Engineering Society LASERS Types of Lasers • Gas Lasers • Excimer Lasers (excited dimer) • F and Cl reacting with inert gases to form tttttnobletgas compounds • High power UV-light • Photolithography, dermatological treatment, tttttdelicate surgery (eye operations) Session 02 ~ 01/12/14

  14. Engineering Society LASERS Types of Lasers • Solid-state Lasers • Crystalline solid doped with ions • High-power lasers (infra-red) • Useful as ultra short-time pulse emission lasers Session 02 ~ 01/12/14

  15. Engineering Society LASERS Types of Lasers • Solid-state Lasers • Holmium-doped YAG crystal lasers • Numerous medical applications • Resurfacing joints, evaporating cancers, tttttpulverizing kidney and gall stones Session 02 ~ 01/12/14

  16. Engineering Society LASERS Types of Lasers • Solid-state Lasers • Semiconductor Lasers and Laser Diodes • Revolutionize Optical Telecommunications • Abundant in CD/DVD optical media storage • Laser Printers Session 02 ~ 01/12/14

  17. Engineering Society LASERS Types of Lasers • Free Electron Lasers • Relativistic electrons oscillate • Color depends on acceleration voltage (λ(VA)) Session 02 ~ 01/12/14

  18. Engineering Society LASERS Section 2 Surgical Application Session 02 ~ 01/12/14

  19. Engineering Society LASERS Traditional Surgery • Highly invasive • Basic tool: the scalpel • Precision defined by knife and tttsurgeon Session 02 ~ 01/12/14

  20. Engineering Society LASERS Laser Surgery • “Laser Scalpel” • Increased precision • Microsurgery • Improve operations tttvia endoscopes • Diagnostic imaging • Numerous other tttapplications Session 02 ~ 01/12/14

  21. Engineering Society LASERS Parameters affecting Laser Radiation • Optical properties of tissue • Reflection • Refraction • Scattering • Absorption • Transmission Session 02 ~ 01/12/14

  22. Engineering Society LASERS Parameters affecting Laser Radiation • Wavelength of emitted light λ • Energy distribution per unit area • Time-variance of radiation 00:00 min • Duration of exposure Session 02 ~ 01/12/14

  23. Engineering Society LASERS Selected Procedure Types • Photoablation • Plasma-Induced Ablation • Photocoagulation Session 02 ~ 01/12/14

  24. Engineering Society LASERS Photoablation • Vaproziation & melting of tissue • Process: • Cell absorbs photons • Heated to boiling point of H2O • Tissue water turns into steam • Result: tissue vaporizes Session 02 ~ 01/12/14

  25. Engineering Society LASERS Plasma Induced Ablation • Breaking of chemical bonds within tissue • Lasers set to high frequency & energy • Exposure to strong electric field • Process: • Exposure causes “optical breakthrough” • Tissue turns into plasma • Controlled photodisruptive effects separate ttttissue Session 02 ~ 01/12/14

  26. Engineering Society LASERS Photocoagulation • Sealing/closing of wounds • Variant of photoablation • Cell heated to 60ºC • Low power but very precise • Creates scar tissue • Stops bleeding and closes wounds Session 02 ~ 01/12/14

  27. Engineering Society LASERS Section 2 Laser Vision Correction Session 02 ~ 01/12/14

  28. Engineering Society LASERS General Information Session 02 ~ 01/12/14

  29. Engineering Society LASERS General Information Session 02 ~ 01/12/14

  30. Engineering Society LASERS General Information Session 02 ~ 01/12/14

  31. Engineering Society LASERS Methods • Flap surgery • Laser-Assisted in Situ Keratomileusis tt(LASIK) • Surface Surgery • Photorefractive keratectomy (PRK) • Non-Surgical • Laser Thermal Keratoplasty (LTK) Session 02 ~ 01/12/14

  32. Engineering Society LASERS Laser-Assisted in Situ Keratomileusis (LASIK) • Preoperative Procedures • Topographic map of the cornea • Eye irregularities examined Session 02 ~ 01/12/14

  33. Engineering Society LASERS Laser-Assisted in Situ Keratomileusis (LASIK) • Operation • Flap creation • Laser remodeling • Reposition of the flap Session 02 ~ 01/12/14

  34. Engineering Society LASERS Laser-Assisted in Situ Keratomileusis (LASIK) • The excimer laser • Wavelength – 193 nm • Eye-tracking system • Energy of each pulse – in the miliwatt range • Each pulse lasts for 10-20 nanoseconds Session 02 ~ 01/12/14

  35. Engineering Society LASERS Laser-Assisted in Situ Keratomileusis (LASIK) • Pros • Lack of discomfort afterwards • Improved healing • Cons • Flap issues • Dry eyes symptoms Session 02 ~ 01/12/14

  36. Engineering Society LASERS Photorefractive Keratectomy (PRK) • Pre-operative procedure – the same as in ttttLASIK • Operation • No flap is required • Removal of corneal tissue Session 02 ~ 01/12/14

  37. Engineering Society LASERS Photorefractive Keratectomy (PRK) • Pros • Not that risky as LASIK. • Good for people with previous eye surgeries • Cons • Slow recovery – 2-4 weeks • Moderate discomfort – 2-4 days Session 02 ~ 01/12/14

  38. Engineering Society LASERS Laser Thermal Keratoplasy (LTK) • Pre-operative procedure (the same as in LASIK) • Operation • zap 16 points on the cornea • change the geometry of the cornea Session 02 ~ 01/12/14

  39. Engineering Society LASERS Laser Thermal Keratoplasy - LTK • Pros • Very safe – no touch procedure. • Immediate vision improvement. • Cons • Vision improvement may wear off. • Risk of under - or overcorrection. Session 02 ~ 01/12/14

  40. Engineering Society LASERS Section 3 Laser Printers Session 02 ~ 01/12/14

  41. Engineering Society Lasers Introduction Session 02 ~ 01/12/14

  42. Engineering Society Lasers The Basics • Static Electricity Session 02 ~ 01/12/14

  43. Engineering Society Lasers Basic Components • Drum • Fuser • Laser • Toner Hopper • Developer Roller • Discharge Lamp • Corona Wire Session 02 ~ 01/12/14

  44. Engineering Society Lasers Photoreceptor Drum Assembly • Photoconductive ttmaterial • Platform for the ttlectrostatic image Session 02 ~ 01/12/14

  45. Engineering Society Lasers Laser Assembly • Laser • Movable mirror • Lens Session 02 ~ 01/12/14

  46. Engineering Society Lasers Applying Toner • Basics of toner • Pigment • Plastic • Toner hopper • Developer unit Session 02 ~ 01/12/14

  47. Engineering Society Lasers Fuser • Heated rollers • Quick operation • Discharge lamp Session 02 ~ 01/12/14

  48. Engineering Society Lasers Color Printers • Same principle • Four main colors • Blue • Red • Yellow • Black Session 02 ~ 01/12/14

  49. Engineering Society Lasers Advantages of a Laser • Speed • Precision • Economy • Affordable price Session 02 ~ 01/12/14

  50. Engineering Society LASERS Q & A Session 02 ~ 06/10/07

More Related