1. ©Sumerra  www.summera.com LASER SAFETY

2. ©Sumerra  www.summera.com Basics of Lasers and Laser Light Laser Beam Injuries Laser Hazard Classes Laser Safety Standards Laser Control Measures COURSE CONTENTS

3. ©Sumerra  www.summera.com L L ight A A mplification by S S timulated E E mission of R R adiation BASICS OF LASERS AND LASER LIGHT

4. ©Sumerra  www.summera.com WAVE NATURE OF LIGHT Light is an electromagnetic wave. Different wavelengths in the visible spectrum are seen by the eye as different colors. Wavelength Red:  = 700 nm Blue:  = 400 nm

5. ©Sumerra  www.summera.com Radio Long WavelengthShort Wavelength Gamma RayX-rayUltravioletInfraredMicrowaves Visible ELECTROMAGNETIC SPECTRUM Lasers operate in the ultraviolet, visible, and infrared. Radio

6. ©Sumerra  www.summera.com STIMULATED EMISSION Incident Photon Excited Atom Laser-Professionals.com Stimulated Photon same wavelength same direction in phase Incident Photon

7. ©Sumerra  www.summera.com CHARACTERISTICS OF LASER LIGHT MONOCHROMATIC DIRECTIONAL COHERENT The combination of these three properties makes laser light focus 100 times better than ordinary light

8. ©Sumerra  www.summera.com LASER COMPONENTS High Reflectance Mirror (HR) Output Coupler Mirror (OC) Active Medium Output Beam Excitation Mechanism Optical Resonator

9. ©Sumerra  www.summera.com HELIUM-NEON GAS LASER Courtesy of Metrologic, Inc.

10. ©Sumerra  www.summera.com Rear Mirror Adjustment Knobs Safety Shutter Polarizer Assembly (optional) Coolant Beam Tube Adjustment Knob Output Mirror Beam Beam Tube Harmonic Generator (optional) Laser Cavity Pump Cavity Flashlamps Nd:YAG Laser Rod Q-switch (optional) Courtesy of Los Alamos National Laboratory NEODYMIUM YAG LASER Laser-Professionals.com

11. ©Sumerra  www.summera.com LASER SPECTRUM 10 -13 10 -12 10 -11 10 -10 10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 1 10 10 2 LASERS 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 10600 UltravioletVisibleNear InfraredFar Infrared Gamma Rays X-Rays Ultra- Visible Infrared Micro- Radar TV Radio violet waves waves waves waves Wavelength (m) Wavelength (nm) Nd:YAG 1064 GaAs 905 HeNe 633 Ar 488/515 CO 2 10600 XeCl 308 KrF 248 2  Nd:YAG 532 Retinal Hazard Region ArF 193 Communication Diode 1550 Ruby 694 Laser-Professionals.com Alexandrite 755

12. ©Sumerra  www.summera.com LASER BEAM INJURIES High power lasers can cause skin burns. Lasers can cause severe eye injuries resulting in permanent vision loss.

13. ©Sumerra  www.summera.com SKIN BURN FROM CO 2 LASER EXPOSURE Accidental exposure to partial reflection of 2000 W CO 2 laser beam from metal surface during cutting

14. ©Sumerra  www.summera.com TYPES OF LASER EYE EXPOSURE EYE INTRABEAM VIEWING LASER DIFFUSE REFLECTION LASER SCATTERED LIGHT MIRROR SPECULAR REFLECTION LASER REFLECTED BEAM ROUGH SURFACE

15. ©Sumerra  www.summera.com HUMAN EYE Choroid Aqueous Cornea Macula Optic Nerve Sclera Vitreous Retina Lens

16. ©Sumerra  www.summera.com 25  Photo courtesy of U S Air Force THERMAL BURNS ON PRIMATE RETINA Laser-Professionals.com

17. ©Sumerra  www.summera.com MULTIPLE PULSE RETINAL INJURY

18. ©Sumerra  www.summera.com Photo courtesy of U S Army Center for Health Promotion and Preventive Medicine EYE INJURY BY Q-SWITCHED LASER Retinal Injury produced by four pulses from a Nd:YAG laser range finder.

19. ©Sumerra  www.summera.com CAUSES OF LASER ACCIDENTS Studies of laser accidents have shown that there are usually several contributing factors. The following are common causes of laser injuries: Inadequate training of laser personnel Alignment performed without adequate procedures Failure to block beams or stray reflections Failure to wear eye protection in hazardous situations Failure to follow approved standard operating procedures or safe work practices

20. ©Sumerra  www.summera.com NON-BEAM HAZARDS  Electrical Hazards  Smoke & Fumes  Mechanical Hazards  Process Radiation  Flashlamp Light  Chemical Hazards

21. ©Sumerra  www.summera.com LASER HAZARD CLASSES Lasers are classified according to the level of laser radiation that is accessible during normal operation.

22. ©Sumerra  www.summera.com CLASS 1 Safe during normal use Incapable of causing injury Low power or enclosed beam CLASS I Laser Product Label not required May be higher class during maintenance or service Nd:YAG Laser Marker

23. ©Sumerra  www.summera.com CLASS 2 CLASS II LASER PRODUCT Laser Radiation Do Not Stare Into Beam Helium Neon Laser 1 milliwatt max/cw Staring into beam is eye hazard Eye protected by aversion response Visible lasers only CW maximum power 1 mW Laser Scanners

24. ©Sumerra  www.summera.com CLASS 3a Small Beam Expanded Beam CLASS IIIa Laser Product LASER RADIATION- AVOID DIRECT EYE EXPOSURE ND:YAG 532nm 5 milliwatts max/CW Aversion response may not provide adequate eye protection CDRH includes visible lasers only ANSI includes invisible lasers CW maximum power (visible) 5 mW Laser Pointers CLASS IIIa LASER PRODUCT Laser Radiation- Do Not Stare Into Beam or View Directly With Optical Instruments Helium Neon Laser 5 milliwatt max/cw

25. ©Sumerra  www.summera.com CLASS 3b Direct exposure to beam is eye hazard Visible or invisible CW maximum power 500 mW CLASS IIIb Laser Product LASER RADIATION- AVOID DIRECT EXPOSURE TO BEAM 2  ND:YAG Wavelength: 532 nm Output Power 80 mW Courtesy of Sam’s Laser FAQ, www.repairfaq.org/sam/lasersam.htm, © 1994-2004 DPSS Laser with cover removed

26. ©Sumerra  www.summera.com CLASS 4 CLASS IV Laser Product VISIBLE LASER RADIATION- AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION 2  Nd:YAG Wavelength: 532 nm Output Power 20 W Exposure to direct beam and scattered light is eye and skin hazard Visible or invisible CW power >0.5 W Fire hazard Photo: Keith Hunt - www.keithhunt.co.ukwww.keithhunt.co.uk Copyright: University of Sussex, Brighton (UK)

27. ©Sumerra  www.summera.com  The Federal Laser Product Performance Standard (FLPPS) of the Center for Devices and Radiological Health (CDRH) This is federal law and applies to the manufacture of lasers.  The American National Standard for Safe Use of Lasers (ANSI Z136.1) This is a VOLUNTARY Standard that applies to the use of lasers. It is “recognized by” : The Occupational Safety and Health Administration (OSHA)  IEC 60825 International Standard LASER SAFETY STANDARDS

28. ©Sumerra  www.summera.com FEDERAL SAFETY REQUIREMENTS FOR CLASS 1 LASER SYSTEMS WITH ENCLOSED CLASS 3b AND 4 LASERS Protective Housing prevents access to laser radiation above safe level. Safety Interlocks terminate laser beam if protective housing in opened. Only authorized personnel may operate laser with interlocks defeated. Warning Labels alert personnel if opening the housing might expose a laser hazard. Viewing Windows and Optics limit laser and collateral radiation to safe levels.

29. ©Sumerra  www.summera.com CDRH CLASS WARNING LABELS CLASS II LASER PRODUCT Laser Radiation Do Not Stare Into Beam Helium Neon Laser 1 milliwatt max/cw CLASS IV Laser Product VISIBLE LASER RADIATION- AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION Argon Ion Wavelength: 488/514 nm Output Power 5 W Class II Class IIIa with expanded beam Class IIIa with small beam Class IIIb Class IV

30. ©Sumerra  www.summera.com INTERNATIONAL LASER WARNING LABELS Symbol and Border:Black Background: Yellow Legend and Border:Black Background: Yellow INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT WAVELENGTH 10,600 nm MAX LASER POWER 200 W EN60825-1 1998

31. ©Sumerra  www.summera.com –Laser Controlled Area –Eye Protection –Barriers, Shrouds, Beam Stops, etc. –Administrative and Procedural Controls –Education and Training CONTROL MEASURES FOR OPEN BEAM LASERS

32. ©Sumerra  www.summera.com CLASS 4 LASER ND:YAG 1064 nm 100 Watts Max. Average Power VISIBLE and/ or INVISIBLE LASER RADIATION-AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION. Controlled Area Warning Sign

33. ©Sumerra  www.summera.com LASER SAFETY EYEWEAR

34. ©Sumerra  www.summera.com EYEWEAR LABELS All eyewear must be labeled with wavelength and optical density.

35. ©Sumerra  www.summera.com LASER PROTECTIVE BARRIER Photo courtesy of

36. ©Sumerra  www.summera.com The person operating the laser always has the primary responsibility for all hazards associated with laser use. WHO HAS PRIMARY RESPONSIBLITY FOR LASER SAFETY ANY TIME A CLASS 4 LASER IS OPERATED?

37. ©Sumerra  www.summera.com Most beam injuries occur during alignment. Only trained personnel may align class 3B or class 4 lasers (NO EXCEPTIONS!) Laser safety eyewear is required for class 3B and class 4 beam alignment. ANSI REQUIRES approved, written alignment procedures for ALL class 4 laser alignment activities and recommends them for class 3B. SAFE BEAM ALIGNMENT

38. ©Sumerra  www.summera.com Operate class 3b and 4 lasers only in an area designed for laser operation and be certain that the beam is terminated on a diffuse beam block at the end of its use path. Do not enter a designated Class 3b or Class 4 laser controlled area (posted with a DANGER sign) without approval from a qualified laser operator. Always wear laser safety eyewear if a class 3b or class 4 invisible beam is accessible. SAFE WORK PRACTICES