ATMIYA INSTITUTE OF TECHNOLOGY

& SCIENCESub.~ PhysicsBatch ~ FY2

Laser & it’s Applications

Light Amplification By StimulatedEmission of Radiation

☺Name ~ Taral Soliya☺Roll no. ~ 47☺Enrollment no. ~ 130030119109

Guiding LightLaser Technology…

Introduction History of the Laser Types of Laser How the Laser works Applications of the Laser Technology

Military Medical Industrial Entertainment Holography

Reference

IntroductionIn the Beginning There Was Light

Industrial Cutting Tools

CD & DVD Players

Dental Drills

Lasik eye Surgery

Tattoo Removal

Surgical Cutting Tool

Printers

The laser was developed about fifty years ago.

Arthur Schawlow and Charles Townes could have had no possible way of knowing the profound effects.

Most people don’t recognize that laser technology is already present as an integral part of our daily lives, allowing us to listen to CD’s, watch DVD’s, and play computer games.

Additionally, lasers are becoming increasingly visible in medicine in ophthalmologic, cosmetic, and general surgery.

This presentation focuses on giving the viewer better insight to the impacts this technology has had on society as a whole as well as an understanding of the functions lasers play in our daily lives.

Introduction

Flashes of Brilliance“A splendid light has dawned on me.” – Albert Einstein In 1917 Einstein published ideas on stimulated

emission of radiation. These ideas laid the basic foundation for the invention of the laser years later.

While investigating what is now known as the photo-electric effect, Einstein noted a statistical tendency which caused photons (particles of light), to want to move together.

Einstein was also able to prove that these emitted photons all traveled in the same direction and with the same frequency as the original photon.

Arthur L. Schawlow

Charles H. Townes

The laser is credited as being invented in 1958 by Charles H.Townes & Arthur L.Schawlow. Townes coined the term “laser” with help from his students. The main differentiating factor between the two devices is that the laser uses light waves as opposed to the microwaves utilized by the maser. Laser = Einstein’ Theories

+ Right Type of Atoms

+ Reflecting Mirrors

Flashes of Brilliance

Types of Laser Outputs Continuous-Wave (CW)

Continuous with respect to time. Higher level must be long-lived relative to lower level, else the laser is self-terminating.

Pulsed (not continuous)Higher peak powers (kW to > MW). Nanosecond pulse widths are typical

Q-Switched“Giant pulse laser” Spoil the cavity resonance so that the lasing threshold is greatly exceeded. Then let it out all at once. Hundreds of MW/pulse achieved.

Mode-LockedPicosecond or less laser pulses. Force all longitudinal modes to be coherent. Generates short (ps or less) and intense (MW) pulses.

Common Laser System

LASERS

Semiconductor

Solid state Liquid Gas LasersDiode Laser

Solid state LiquidNeodymium Yag Laser

Ruby laser

Gaseous

Varieties of Lasers

Courtesy of Los Alamos National LaboratoryRear Mirror

Adjustment Knobs Safety Shutter Polarizer Assembly (optional)

CoolantBeamTube Adjustment

KnobOutputMirror

Beam

Beam Tube

Q-switch(optional)

Nd:YAGLaser Rod

Flashlamps Pump

CavityLaser Cavity

Medium ~ Neodymium-Doped Yttrium Aluminum Garnet CrystalState ~ SolidExcitation Beam ~ Diode Laser 1064 nm infraredUses ~ Cataract ,Glaucoma , Gingivectomy surgeries

Neodymium YAG Laser

QD Lasers

Optics

Data com

network

Telecom netw

ork

High speed QDL Advantages• Directly Modulated

Quantum Dot Lasers• Data com application• Rate of 10Gb/s

• Mode-Locked Quantum Dot Lasers

• Short optical pulses• Narrow spectral width• Broad gain spectrum• Very low α factor-low chirp

• InP Based Quantum Dot Lasers

• Low emission wavelength• Wide temperature range• Used for data transmission

Quantum Dot Laser

Varieties of LasersLaser type Wavelengths (nm) Power

Output

Helium–neon 633,1152 0.1–50 mW CWArgon–ion 351–529 several 5 mW–25 W CWHelium–cadmium 325-442 1–50 mW CWDye (Ar pump) 400–1000 5 W CW, tunableYd:YAG 1064 0.1–500 W PulsedNd:YAG 1064 0.5–1000 W CWCO2 10600 1–100 W CWGaAlAs 750–900 1–100 mW CWInGaAsP 1100–1600 1–100 mW CWTi:sapphire 700–1100 0.1–1 W CW, tunable

Gamma Rays X-Rays Ultra- Visibleviolet

Infrared Micro-waves

Radarwaves

TVwaves

Radiowaves

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 1021 10

Wavelength (m)

LASERS

Far Infrared

200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 10600

Wavelength (nm)ArF193

XeCl308

HeNe633

2

Ruby694Alexandrite

CO2

10600

CommunicationDiode1550KrF

248Ar

488/515GaAs905

Nd:YAG1064Nd:YAG

532755

UltravioletRetinal Hazard Region

Far Infrar

Visible Near Infrared

Electromagnetic Spectrum

Shedding Some Light…How the Laser Works

Flash Tube

Partially Reflectiv

eMirrorMirrored

Surface

Atoms become excited

The flash tube fires light at the ruby rod. The light excites the atoms.

Emitted Light

Some ofthese atomsemit

photons.

Monochromatic, single-phase, calumniated light leaves the ruby through the half-silvered mirror ~ laser light!

Some of these photons run in a direction parallel to the ruby's axis.

So, they bounce back and forth off the mirrors. As they pass through the crystal, they stimulate emission in other atoms.

Shedding Some Light…How the Laser Works

Applications of LaserThe Weighty Implications of Laser Technology

Applications of Laser

Technology

Medical Optical & General

surgery Tattoo removal

Military Weapon

s Radar

Entertainment CD & DVD Players Video Game

system

Telecommunications

Holograms Satellites Computer Mouse

Industries Metal

cutting Welding

However, laser technology has also helped advance the U.S. military by offering new possibilities in warfare, such as:

Non-Lethal Weapons

Lasers & MilitaryOminous lights

The Reagan Star-Wars era program did much to initially support laser weapons research, resulting in many of today’s military advancements.

Optical Guidance, Night Vision & Thermal homing missiles

Lasers are used to drive fusion machines fueling thermonuclear explosions and used in most nuclear devices.

The most potent and deadly application of laser technology is the Space Based Laser.

As tensions over the growing arsenals of nations grow, arms agreements have done little to slow down the development of these technologies.

Lasers & MilitaryOminous lights

High-intensity lasers can be used in Omni-directional bombs or flares which can flash-blind personnel as well as degrade sensors and night vision devices.

Low energy lasers can be directed or aimed at specific targets to blind personnel or sensors either temporarily or permanently. The most advanced blinding lasers oscillate between numerous colors to make goggles and other countermeasure ineffective.

Lasers can also be used to make a gun or other weapon too hot to hold.

Lasers & MilitaryOminous lights

THERMAL IMAGING

Although military applications of Laser Technology have such potentially devastating implications for humanity.

Without the national security that these weapons provide, our country would be vulnerable to outside attack.

However, it is up to us to decide whether our vision for the future is the endless quest for military superiority, or whether our ultimate goal is peace on earth.

Lasers & MilitaryOminous lights

Advantages for the Laser as a Medical Cutting Tool The laser is extremely precise, and can be tuned

to work on a micro-level, barely visible to the human eye.

Reduces pain & trauma for the patient. Lasers can be inserted inside the body with little

risk or discomfort. Certain conditions which were once inoperable

due to the accuracy of incisions necessary are now possible.

Incisions can be guided by computers. Speeds healing – thereby shortening costly

hospital stays. compact lasers can be inserted inside the body

with little risk or discomfort, going places and performing surgeries that were not humanly possible before.

Lasers & MedicineGoing where no man has gone before

Lasers & MedicineGoing where no man has gone before

Advantages for the Laser as a Medical Cutting Tool The precision and accuracy with

which lasers can cut is so exact that it would be impossible for a human to recreate. Pictured on the right is a human hair treated by an excimaer laser- the cuts are so tiny that they would not be visible to the human eye! The excimaer laser is typically used to perform Lasik eye surgery.

The laser as a cutting tool also has considerable industrial implications.

Lasers guided by computers can eliminate human error in surgery.

Lasers & MedicineGoing where no man has gone before

Laser Technology’s Contribution to Ophthalmology Advances in laser technology have made

substantial improvements in the field of ophthalmology.

Prior to these advances the solutions for those genetically pre-disposed to bad eyesight were limited: Glasses ~ which are bulky and often carry social

stigma Contacts – which often leave eyes susceptible to

infection, require daily cleaning, and cannot be worn comfortably overnight or for extended periods of time

What is Laser Surgery ? The goal in laser eye surgery is to reshape the cornea,

changing the focal point of the eye. Ideally the focal point is changed so it focuses perfectly on the retina.

Lasers & MedicineGoing where no man has gone before

If you are nearsighted, the image comes into

focus before it hits your retina.

If you are farsighted, the image doesn’t come into focus

before it hits your retina.

In a good eye the image is focused on

the retina.

After applying anesthetizingdrops, the surgeon marks theeye to indicate where the flapwill be cut and then replaced.

A suction ring holds the eyestill and pressurizes it soit is firm enough to cut.

The microkeratome slices atiny flap in the cornea.

The flap is moved out of theway, but it is still attached. The laser removes tissue toreshape the cornea. The flap

is replaced on the eye.

Lasers & MedicineGoing where no man has gone before

How does Laser Surgery Works ?

Lasers & IndustrySomething Heavy

Lasers are used now for cutting, drilling and welding of metals and other materials.

LIDAR - Light Detection & Ranging (Mines)

Laser light is used to collect the information about the prefixed prices of various products in shops and business establishments from the bar- code printed on the product.

One of the most popular applications of laser technology, the Compact Disc Player, marked a revolution in digital video and sound technology.

Lasers & EntertainmentThe Bright Side & The Dark Side

The CD Player works by using a laser beam to determine the lengths of a series of tiny ridges inside a compact disk.

The music is digitally encoded in the ridge lengths which are measured by the reflected laser.

Lasers & EntertainmentThe Bright Side & The Dark Side

How does CD Player Works ?

Inside a CD or DVD Player

Lasers & HolographyProduction of Holo things

Possible medical applications using the technology Surgical procedures (using tracking capabilities) Rehabilitation techniques & Gaming

Holography is the production of holograms by the use of laser.

Lasers & Safety eyewearBe careful

Reference How Stuff Works (howstuffworks.com) Wikipedia (wikipedia.org) Principle of Physics (Book by Dr. Serway)

THANK YOU