Lasers are used in optical disk drives, laser printers, barcode scanners, DNA sequencing instruments, fiber-optic, semiconducting chip manufacturing (photolithography), and free-space optical communication, laser surgery and skin treatments, cutting and welding materials, military and law enforcement devices for …

The three main characteristics of laser is that it is coherent, dierctional and monochromatic.

• Laser is a light of single wavelength or colour.
• Laser is a narrow beam that is emitted in a specifi direction.
• Laser lights are in phase in space and time.

Explanation: The lasers are highly directional having almost no divergence. The output beam of laser has a well-defined wave front due to which it can be focused on a point. Lasers are highly intense compared to ordinary light. They are monochromatic and coherent.

Lasers are key components of many of the products that we use every day. Consumer products like Blu-Ray and DVD players rely on laser technology to read information from the disks. Bar code scanners rely on lasers for information processing. Lasers are also used in many surgical procedures such as LASIK eye surgery.

(i) the system must be in a state of population inversion. (ii) the excited state of the system should be in metastable state. (iii) the atom should be in lower energy state.

I. Specific Laser Types:

• Helium Neon Laser: The first CW system was the helium neon (HeNe) gas mixture.
• Argon, Krypton, and Xenon Ion Lasers.
• Carbon Dioxide Laser.
• ND:YAG Laser Systems:
• Excimer Lasers:
• Semiconductor Diode Lasers.
• Other Lasers:

In lasers, photons are interacted in three ways with the atoms: Absorption of radiation. Spontaneous emission. Stimulated emission.

A laser is created when the electrons in atoms in special glasses, crystals, or gases absorb energy from an electrical current or another laser and become “excited.” The excited electrons move from a lower-energy orbit to a higher-energy orbit around the atom’s nucleus. Second, laser light is directional.

The Extreme Light Infrastructure for Nuclear Physics (ELI-NP) project in Romania has recently reached a significant milestone: the ultra-high intensity laser system developed by Thales has successfully generated its first pulses at a peak power level of 10 petawatts (1015 W).

The neodymium-YAG laser emits infrared light at 1.064 micrometers. Gas lasers (helium and helium-neon, HeNe, are the most common gas lasers) have a primary output of a visible red light. CO2 lasers emit energy in the far-infrared, 10.6 micrometers, and are used for cutting hard materials.

There are 3 types of lasers: CO2 (gas lasers), Fiber lasers and Nd:YAG or Nd:YVO (vanadate crystal lasers). Each use a different base material to stimulate the laser either electrically with a gas mixture or passed through physical diodes.

Liquid lasers are optically pumped lasers in which the gain medium is a liquid at room temperature. And the most successful of all liquid lasers are dye lasers. These lasers generate broadband laser light from the excited energy states of organic dyes dissolved in liquid solvents.

Nanometers