LASER More Than You Know

LASERMore Than You KnowSudhanshu Rathore 2nd yr Electrical

Table Of ContentsIntroductionThe BasicsAbsorbing EnergyThe Laser/Atom ConnectionLaser LightHow does Laser differ from Other Light?Components Of LaserApplications Of LaserEveryday ApplicationsBibliography

IntroductionLASER is an acronym for L = LightA = AmplificationS = by StimulatedE = EmissionR = of RadiationAlmost everyone probably knows that the police use laser when they measure speed, but how many know that you also use laser several times during an ordinary day? You'll find it in CD players, laser printers and much, much more.The power contained in laser is both fascinating and frightening.

The BasicsAtoms are constantly in motion. They continuously vibrate, move and rotate.Atoms can be in differentstates of excitation, i.e., they can have different energies.Apply a lot of energy to an atom, it can leave what is called theground-state energy leveland go to anexcited level.

Absorbing Energy This reflects the core idea of how atomswork in terms of lasers.Once an electron moves to a higher-energy orbit, it eventually wants to return to the ground state. When it does, it releases its energy as aphoton-- a particle oflight. For example, when the heating element in atoasterturns bright red, the red colour is caused by atoms, excited by heat, releasing red photons. When you see a picture on aTV screen, what you are seeing is atoms, excited by high-speed electrons, emitting different colours of light. Anything that produces light --fluorescent lights,gas lanterns,incandescent bulbs-- does it through the action of electrons changing orbits and releasing photons.

The Laser/Atom ConnectionAlaseris a device that controls the way that energized atoms release photons. "Laser" is an acronym forlight amplification by stimulated emission of radiation, which describes very succinctly how a laser works.In a laser, the lasing medium is pumped to get theatomsinto an excited state. The electron absorb some energy to reach this excited level and then release this energy.

The Laser/Atom ConnectionThisemitted energycomes in the form ofphotons(light energy).The photon emitted has a very specificwavelength(colour) that depends on the state of the electron's energy when the photon is released.

Laser Light Laser light has the following properties:The light released ismonochromatic.It contains one specific wavelength of light (one specific colour). The light released iscoherent. It is organized -- each photon moves in step with the others. The light is verydirectional. A laser light has a very tight beam and is very strong and concentrated.To make these three properties occur takes something calledstimulated emission.

How Does Laser Light Differ from Other Light?Light is an electromagnetic wave.Each wave has brightness and colour, and vibrates at a certain angle.This is also true for laser light but it is more parallel than any other light source.Every part of the beam has (almost) the exact same direction and the beam will therefore diverge very little.

Three - Level Laser

Components Of LASERSGain medium is a material with properties that allow it to amplify light by stimulated emission.Laser pumping energy is required for the gain medium to amplify light. The energy is typically supplied as an electrical current or as light at a different wavelength.High reflector are used to bounce back and forth the light between the mirrors, passing through the gain medium and being amplified each time.

Components Of LASERS Output coupler decides if light coming out of the laser will be spread out or form a narrow beam. This type of device is called as a laser oscillator.Laser beam has additional elements such as polarization and wavelength which affect the properties of emitted light.

Applications Of LASERSIndustrial Applications of Laser : Laser can be found in a broad range of applications within industry, where it can be used for such things as pointing and measuring. Within the pulp mill industry the concentration of lye is measured by observing how the laser beam refracts in it.In the mining industry, laser is used to point out the drilling direction.

Applications Of LASERS2. Environmental ApplicationsUsage to determine from a distance the environmental toxins in a column of smoke.To supervise wastewater purification.

Applications Of LASERS3. ResearchExtremely important to researchers within physics, chemistry, biology and medicine, used to:register ultra fast chemical processes, like-bonding between atoms to form moleculesstudy the process when cells split, or a virus enters into a cellmanipulate molecules down to extremely low temperatures;transfer as much energy as possible to different materials in a short time to obtain different types of emissions.

Applications Of LASERS4. CommunicationsWorks as a light source in all fibre optics in use. Has greater bandwidth (potentially 100,000 times greater) than an ordinary copper cable.Is insensitive to interference from external electrical and magnetic fields. Crosstalk (hearing someone else's phone call) is of rare occurrence.

Applications Of LASERS5. MedicineUsed in medicine to improve precision work like surgery.Brain surgery is an example of precision surgery that calls for the surgeon to reach the intended area precisely. Birthmarks, warts and discolouring of the skin can easily be removed with an unfocused laser. Operations are quick and heal quickly and, best of all, they are less painful

Everyday ApplicationsDVD/VCD PlayersLaser PrintersLaser Pointers and WritersLaser SightsSpeed Measurements using LaserLaser Distance MeterBar Code Readers in Retail StoresBy Hunters/Shooters instead of ordinary telescope sights

Bibliographywww.howstuffworks.comwww.nobleprize.orgwww.laserinternational.orgwww.laser.comwww.hyperphysics.phy-astr.gsu.eduwww.library.thinkquest.orgwww.xamplified.comwww.wikipedia.comwww.thebigger.comwww.britannica.com

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