TYPES AND APPLICATIONS OF LASER

What is the process responsible for producing photons in diode laser?

• Fermi level shift

• Majority carrier injection

• Carrier freeze out

• Electron-hole recombination

What are three types of Laser?

• gas,solid,diode

• diode,inverted,pointer

• gas,metal vapor,rock

• pointer,diode,CD

Example of solid state laser is

• He-Ne laser

• $co_2$ laser

• Nd:YAG Laser

• Dye laser

Example for direct band gap semiconductors are

• GaAs

• Ge

• Si

• AlSb

Wavelength produced by semiconductor laser is

• 5000 Angstrom

• 6000 Angstrom

• 8400 to 8600 Angstrom

• None

How can lasers remove tattoos from skin?

• by burning away skin cells containing tattoo ink

• by chemically changing tattoo ink so that it is invisible

• by breaking down the molecules that make up the ink

• laser tattoo removal is currently impossible

which is an application of laser?

• medical application 
• Communication 
• cutting metals
• all of the above 

Life time of metastable state is

• 10^-8 s

• 10^-10 s

• 10^-3 s

• 10^-9 s

Which type of laser is best suited for use in CD/DVD players?

• gas laser

• laser diode

• solid-state laser

• excimer laser

What is the purpose of a laser in a laser printer?

• to burn an image onto paper

• to electrically charge the paper so that it will attract toner particles

• to transmit the image to be printed from the computer to the printer

• to determine how much ink is left in the printer