Laser

the ppt on laser will help you to understand concept of laser easily

1. LASER Prepared By :- Rushit Patel

2. L Light A Amplified by S Stimulated E Emission of R Radiation

3. What Is LASER? A LASER is a device that transforms light of various frequencies into a chromatic radiation in the visible, infrared, and ultraviolet regions with all waves in phase capable of transferring immense Heat and power when focused at close range.

4. INVENTORS OF LASER Theodore Harold Maiman

5. Charles Townes it was based on Einstein’s idea of the “particle wave duality” of light Originally called MASER

6. Coherent And Incoherent Light

7. AMPLIFICATION Is a part of a process that occurs inside the laser. An optical cavity is at the center of the laser device & the core is comprised of chemical elements, molecules or compounds – “ Active Medium ” Lasers are generically named for the material of the active medium

8. Hollow Waveguide or Tube Has an interior finish mirror Laser energy is reflected along this tube and exits through a hand piece Strikes the tissue in a non-contact manner An accessory tip of sapphire or hollow metal can be connected

9. WAVEGUIDE TUBE

10. Glass fiber Optic Cable More flexible than waveguide Less weight and less resistance in movement Smaller diameter (200-600 μ m) Fragile & can’t be bent in sharp angles

11. Glass Fiber Optic Cable

12. Fundamentals Of Laser The light emitted from a laser is monochromatic , that is, it is of one color/wavelength. In contrast, ordinary white light is a combination of many colors (or wavelengths) of light. Lasers emit light that is highly directional , that is, laser light is emitted as a relatively narrow beam in a specific direction. The light from a laser is said to be coherent , which means that the wavelengths of the laser light are in phase in space and time. These three properties of laser light are what can make it more hazardous than ordinary light. Laser light can deposit a lot of energy within a small area.

13. Common Component Of All Laser Active Medium The active medium may be solid crystals such as ruby or Nd:YAG, liquid dyes, gases like CO2 or Helium/Neon, or semiconductors such as GaAs . Active mediums contain atoms whose electrons may be excited to a metastable energy level by an energy source. Excitation Mechanism Excitation mechanisms pump energy into the active medium by one or more of three basic methods; optical, electrical or chemical. High Reflectance Mirror A mirror which reflects essentially 100% of the laser light. Partially Transmissive Mirror A mirror which reflects less than 100% of the laser light and transmits the remainder.

14. INCANDENT VS LASER LIGHT Many wavelengths Multidirectional Incoherent Monochromatic Directional Coherent

15. GAS LASER Gas lasers consist of a gas filled tube placed in the laser cavity. A voltage (the external pump source) is applied to the tube to excite the atoms in the gas to a population inversion. The light emitted from this type of laser is normally continuous wave (CW).

16. HELIUM NEON GAS LASER

17. ND : YAG Laser Nd:YAG ( neodymium-doped yttrium aluminium garnet ; Nd:Y 3 Al 5 O 12 ) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, Nd (III), typically replaces a small fraction (1%) of the yttrium ions in the host crystal structure of the yttrium aluminium garnet (YAG), since the two ions are of similar size.It is the neodymium ion which provides the lasing activity in the crystal, in the same fashion as red chromium ion in ruby lasers YAG Rod

18. Nd:YAG lasers are optically pumped using a flashtube or laser diodes. These are one of the most common types of laser, and are used for many different applications. Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so-called Q-switching mode: An optical switch is inserted in the laser cavity waiting for a maximum population inversion in the neodymium ions before it opens. Then the light wave can run through the cavity, depopulating the excited laser medium at maximum population inversion. In this Q-switched mode, output powers of 250 megawatts and pulse durations of 10 to 25 nanoseconds have been achieved.The high-intensity pulses may be efficiently frequency doubled to generate laser light at 532 nm, or higher harmonics at 355, 266 and 213 nm.

19. Application of LASER Many scientific, military, medical and commercial laser applications have been developed since the invention of the laser in 1958. The coherency, high monochromaticity, and ability to reach extremely high powers are all properties which allow for these specialized applications.

20. COMPUTING SPEED At present the computing speed ranges from 256 kilobits per second to 1 gigabit per second, which is slow for the present world. The ability to achieve a speed of 25 gigabits per second can be done with the use of laser chips. Lasers are already used to transmit high volumes of computer data over longer distances for example, between offices, cities and across oceans using fibre-optic cables. In computer chips, datamoves at great speed over the wires inside, then slows when it is sent chip-to-chip inside a computer.

21. MILITARY DEFENCE

22. METEOROIDS ATTACK The concept which was used for military defense can be used to destroy the meteoroids coming towards earth. These incoming meteoroids can be shattered into pieces, thus saving our earth from any major destruction. A group of strong laser beams are focused together to the target and the target is shattered off.

23. MEDICAL FIELD Cosmetic surgery (removing tattoos, scars, stretch marks, sunspots, wrinkles, birthmarks, and hairs). Now a days EYE surgery can also be done with help of laser. "No-Touch" removal of tumors, especially of the brain and spinal cord.

24. CURIOSITY USING IT’S LASER DEVICE IN ITS MISSION

25. INDUSTRIAL AND COMMERCIAL Leveling of ceramic tiles floor with a laser device

26. OTHER APPLICIATIONS Cutting and  peening  of metals and other material, welding, marking, etc. Laserdrilling , Guidance systems ,Rangefinder/ surveying, LIDAR/ pollution monitoring. To store and retrieve data in optical discs. In  laser printers : gas and diode lasers play a key role in manufacturing high resolution printing plates and in image scanning equipment.

27. Diode lasers are used as a light switch in industry, with a laser beam and a receiver which will switch on or off when the beam is interrupted, and because a laser can keep the light intensity over larger distances than a normal light, and is more precise than a normal light it can be used for product detection in automated production.

28. Laser Beam Injuries High Beam laser can cause skin burns. LASERs can cause serve eye injuries which can cause permanent vision loss.

29. Approximate Power Limit for visible wavelength only Class 4 Unsafe for eyes Unsafe for skin 0.5W Class 3B Unsafe for eyes Generally safe for skin 5mW Class 3R Safe with (0.25 s.) aversion response no viewing aids 0.5W Class 2M Visible wavelengths only Safe with no viewing aids 1mW Class 2 Visible wavelengths only Safe with (0.25 s.) aversion response including viewing aids 0.5W Class 1M Safe with no viewing aids 220 μ W to 0.4 μ W Class 1 No precautions required Laser Classification Table

30. GENERAL LASER LAB SAFETY Clothing : Long sleeve clothing should be worn to protect skin. Wear enclosed footwear in labs . Jewelry : watches & rings which could reflect beams should not be worn. Viewing Aids : Never use microscopes, telescopes, magnifying glasses etc to view laser beams

31. GENERAL LASER LAB SAFETY Never directly view a laser beam. Never point a laser pointer at a person. Never over-ride interlocks Never remove covers from equipment without approval from supervisors – laser, high voltages and other hazards are present.

32. THANK YOU