Laser

A laser is a device that stimulates atoms or molecules through an optical amplification process, emitting a beam of coherent light. The word laser is an acronym for “light amplification by the stimulated emission of radiation.” Laser light is created by electrons within an atom absorbing the energy from an electric current or a light source. This energy excites electrons into a higher energy state, emitting photons as they return to their original ground state.

A coherent beam of light means the photons are moving in the same direction with the same wavelength. Lasers achieve this through energized electrons traversing an optical "gain medium," such as a solid material like glass, or a gas. The specific wavelength is determined by the amount of energy produced when stimulated electrons drop to a lower orbit. A particular wavelength can be produced by tailoring the material of the gain medium.

There are many types of lasers including:

Einstein introduced the concept of stimulated emission in 1917, laying the foundation for laser theory. The first working laser is credited to Theodore Maiman in 1960 while working at Huges Research lab. Key contributions to laser development include Charles Townes (Columbia University) and Arthur Schawlow (Bell Laboratories), workwho worked on the maser (Microwave Amplification by Stimulated Emission of Radiation), a precursor to the laser. In 1958, they published a key theoretical paper, pushing forward laser development.

In 1960, the pair werewas awarded the first laser patent. Previously, Gordon Gould, a graduate student at Columbia University, filed a patent in April 1959 that was denied by the US US patentPatent Office Office in favor of Schawlow and Townes's optical maser patent. This leadled to a thirty-year patent war, andwith Gould eventually winning 48forty-eight patents years later for commercially valuable aspects of lasers, including optical pumping and specific applications.

1. Gain medium that is capable of sustaining stimulated emission.
2. Energy source to pump the gain medium.
3. Total reflector for reflecting the beam back through the gain material
4. Partial reflector
5. Laser beam output

The wavelength and power of the laser beam produced is determined by the gain medium and resonator.

• A gain medium that is capable of sustaining stimulated emission
• An energy source to pump the gain medium
• A total reflector for reflecting the beam back through the gain material
• A partial reflector
• Laser beam output

The wavelength and power of the laser beam produced are determined by the gain medium and resonator.

The two reflectors (mirrors) bounce photons back and forth through the cavity containing the gain medium. This gain medium is designed such that when an energy source is provided, the photons stimulate electrons producing new photons of almost the exact same wavelength. The photons produced travel in the same direction, reflecting between the mirrors and repeating this process until they are amplified to the point they move past the partial reflector.

A laser is a device that stimulates atoms or molecules through an optical amplification process, emitting a beam of coherent light. The word laser is an acronym for “light amplification by the stimulated emission of radiation.” Laser light is created by electrons within an atom absorbing the energy from an electric current or a light source. This energy excites electrons into a higher energy state emitting photons as they return to their original ground state.

A coherent beam of light means the photons are moving in the same direction with the same wavelength. Lasers achieve this through energized electrons traversing an optical "gain medium" such as a solid material like glass, or a gas. The specific wavelength is determined by the amount of energy produced when stimulated electrons drop to a lower orbit. A particular wavelength can be produced by tailoring the material of the gain medium.

There are many types of lasers including:

• Gas lasers
• Fiber lasers
• Solid-state lasers
• Dye lasers
• Diode lasers
• Excimer lasers

Lasers have applications in a range of products including consumer products, medical applications, communications, and scientific research (spectroscopy, fusion, etc.).

Einstein introduced the concept of stimulated emission in 1917, laying the foundation for laser theory. The first working laser is credited to Theodore Maiman in 1960 while working at Huges Research lab. Key contributions to laser development include Charles Townes (Columbia University) and Arthur Schawlow (Bell Laboratories) work on the maser (Microwave Amplification by Stimulated Emission of Radiation), a precursor to the laser. In 1958 they published a key theoretical paper pushing forward laser development.

In 1960 the pair were awarded the first laser patent. Previously Gordon Gould a graduate student at Columbia University filed a patent in April 1959 that was denied by the US patent Office in favor of Schawlow and Townes's optical maser patent. This lead to a thirty-year patent war and Gould eventually winning 48 patents years later for commercially valuable aspects of lasers including optical pumping and specific applications.

Diagram showing the basic components of a laser.

Lasers share a basic set of components:

1. Gain medium that is capable of sustaining stimulated emission.
2. Energy source to pump the gain medium.
3. Total reflector for reflecting the beam back through the gain material
4. Partial reflector
5. Laser beam output

The wavelength and power of the laser beam produced is determined by the gain medium and resonator.

The two reflectors (mirrors) bounce photons back and forth through the cavity containing the gain medium. This gain medium is designed such that when an energy source is provided the photons stimulate electrons producing new photons of almost the exact same wavelength. The photons produced travel in the same direction, reflecting between the mirrors repeating this process until they are amplified to the point they move past the partial reflector.