Lasers are really useful. Think about CD & DVD player, bar code reader, machine for cutting metals, and other more stuffs. They are made with lasers. How could laser do we those? :
- CD & DVD player, it use laser when you want to watch movie / TV or listen music and others.
- In stores, you may see the bar codes reader to calculate the total payment with bar codes reader; used by laser.
- TV & Telephones use signals over the cables with lasers. You may call people, watch TV, connect with TV and play games, and others.
- Also, surgeon use the laser for eye surgery; it is painless because the laser pass through patient's eyes.
Also, the laser stands for Light Amplification by Stimulated Emission of Radiation
How is laser light different from natural light?
First, what is natural light?
How do laser works?
- A high-voltage electric supply makes the tube flash on and off.
- Every time the tube flashes, it produce energy into the ruby crystal. It makes the flashes put energy into the crystal in the form of photons.
- Atoms in the ruby crystal soak up this energy. This process is called absorption. When an atom absorbs a photon of energy, one of its electrons jumps from a low to higher level of energy; puts the atom in excitement but makes it unstable because the electron can stay in the higher energy level for a few milliseconds. It goes back to its original level; giving off the energy it absorbed. This process is called spontaneous emission.
- The photons that atoms give off, zoom up and down inside the ruby crystal, traveling like a light traveling speed.
- Every so often, one of these photons hits an excited atom. Then, the excited atom gives off two photons. This is called stimulated emission. Now one photon has produced two, so the light has been bigger.
- A mirror at one end of the laser tube keeps the photons bouncing back and forth inside the crystal.
- A partial mirror at the other end of the tube bounces some photons back into the crystal but lets some escape.
- The escaping photons make a very narrow, bright beam of laser light.
Summary of my Findings
Bibliography - Research
- http://spaceplace.nasa.gov/laser/en/ : What is Laser? :: NASA space place
- http://science.howstuffworks.com/laser.htm : How Laser Works - HowStuffWorks
- http://www.ionmax.com.au/natural-light/ : Natural Light
- http://www.lasertech.com/How-Lasers-Work.aspx : Laser Technology - How Lasers Work
- http://www.explainthatstuff.com/lasers.html : How do lasers work? | Who invented the laser?
- http://whatis.techtarget.com/definition/laser : What is laser? - Definition from Whatis.com
- http://www.planet-science.com/categories/over-11s/technology/2012/01/what-is-a-laser.aspx : What is a laser?
Bibliography - Pictures
- http://spaceplace.nasa.gov/laser/en/ : What is Laser? :: NASA space place (Diagram)
- https://www.google.com.hk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj24Y_27cPJAhWEoJQKHYx9A78QjRwIBw&url=http%3A%2F%2Fwww.grmusic.net%2Fcd-dvd-dups.html&psig=AFQjCNHMGvusrcRaokzjeJeTHbAQK1_5Lg&ust=1449375307675805 : CD & DVD
- 256 × 256 - prestamonster.com : Bar code reader
- 327 × 327 - confused.com : TV & Telephone
- http://www.explainthatstuff.com/lasers.html : How do lasers work? | Who invented the laser? (Diagram)