What are the Different Types of Lasers?

Laser-a device that emits laser light. The first microwave quantum amplifier was made in 1954 and a highly coherent microbeam was obtained. In 1958 AL Shawlow and CH Towns extended the microwave quantum amplifier principle to the optical frequency range. In 1960, TH Mayman and others made the first ruby laser. In 1961, A. Jia Wen and others made a He-Ne laser. In 1962, RN Hall and others created a gallium arsenide semiconductor laser. In the future, there will be more and more types of lasers. According to the working medium, lasers can be divided into four categories: gas lasers, solid-state lasers, semiconductor lasers, and dye lasers. Recently, free-electron lasers have also been developed. High-power lasers are usually pulsed outputs. ^[1]

Laser

Laser-a device that emits laser light. The first microwave quantum amplifier was made in 1954 and a highly coherent microbeam was obtained. In 1958 AL Shawlow and CH Towns extended the microwave quantum amplifier principle to the optical frequency range. In 1960, TH Mayman and others made the first ruby laser. In 1961, A. Jia Wen and others made a He-Ne laser. In 1962 RN Hall and others created gallium arsenide

The word laser in English is derived from the original acronym LASER. LASER means the abbreviation of the English word "stimulated radiation amplifier".

The key concept in laser technology was established as early as 1917 when Einstein proposed "stimulated radiation". The word laser was once controversial; Gordon Gould was the first person in the record to use the term.

1953 American physicist

The laser was first built by scientist Gordon Gould in 1958, but the related paper was not published until 1959, but was rejected during the patent application process, because his mentor was Charles, the inventor of the Maser technology Townes (invented the technology that produces microwave output). Due to the influence of the instructor, the patent has not been approved. It was not until 1977 that laser patents were granted in the United States.

The long-term patent battle is more beneficial to Gould, because when he obtained the patent, the laser had already been used on a large scale and was subject to the limitation of the patent protection period. If the patent was applied for, it would be approved because it was not widely used and it would not make money. Too much money.

The light quality and spectral stability of the laser can be used in many ways.

Ruby laser: The original laser was a ruby excited by a bright flashing light bulb. The laser produced was a "pulse laser" rather than a continuous and stable beam. The quality of the beam produced by this laser is fundamentally different from the laser produced by the laser diodes we use today. This intense light emission, which lasts only a few nanoseconds, is ideal for capturing easily moving objects, such as portraits of holographic portraits. The first laser portrait was born in 1967. Ruby lasers require expensive rubies and can only produce transient pulsed light.

He-Ne laser: In 1960 scientists Ali Javan, William R. Brennet Jr., and Donald Herriot designed the He-Ne laser. This is the first gas laser, and this laser is commonly used by holographic photographers. Two advantages: 1. Generate a continuous laser output; 2. Do not need a flash bulb for optical excitation, and use electricity to excite the gas.

Laser diode: Laser diode is one of the most commonly used lasers at present. The phenomenon of spontaneous recombination of electrons and holes on both sides of the diode's PN junction is called light emission.

All lasers can be classified into the following categories according to the physical state of the working material:

Tunable laser

Tunable laser refers to a laser that can continuously change the laser output wavelength within a certain range (see Laser). This laser has a wide range of applications, such as spectroscopy, photochemistry, medicine, biology, integrated optics, pollution monitoring, semiconductor material processing, information processing, and communications.

Single-mode laser

Lasers with single transverse mode (generally fundamental mode) and multiple longitudinal modes.

Chemical oxygen iodine laser

The chemical oxygen iodine laser is an airborne laser. The airborne laser system uses a modified Boeing 747-400F aircraft as the launch platform (codename YAL-1A), and uses a chemical oxygen iodine laser that generates high-energy lasers as the core. Directed energy weapons that directly damage or invalidate a target.

CO2 laser

The carbon dioxide laser is a gas laser using CO2 gas as a working substance. The discharge tube is usually made of glass or quartz material, which is filled with CO2 gas and other auxiliary gases (mainly helium and nitrogen, and usually a small amount of hydrogen or xenon); the electrode is generally a hollow cylinder made of nickel; a resonant cavity One end is a gold-plated total mirror, and the other end is a partial mirror ground with germanium or gallium arsenide. When a high voltage is applied to the electrode (usually DC or low-frequency AC), a glow discharge is generated in the discharge tube. A laser output is provided at one end of the germanium mirror, and its wavelength is in the mid-infrared band near 10.6 microns; generally a better tube . A discharge area of about one meter can obtain continuous output power of 40 to 60 watts. CO2 laser is a relatively important gas laser

Liquid laser

Liquid lasers are also called dye lasers because the active substance of these lasers is a solution of certain organic dyes dissolved in liquids such as ethanol, methanol, or water. In order to excite them to emit laser light, high-speed flashlights are generally used as laser sources, or other lasers emit short light pulses. The laser emitted by a liquid laser is of great significance for spectral analysis, laser chemistry, and other scientific research. ^[4]

Digital laser

Digital lasers replaced one of the mirrors with a "spatial light modulator." The "spatial light modulator" is like a reflective micro LCD display. "You only need to enter a specific image into the display through a computer to get the required laser mode. Its biggest feature is that it does not need to design a new laser for each laser Just transform the picture on your computer to get the desired beam shape.

Digital lasers can create almost any laser mode. Previously, each beam required a separate laser. To this end, many people need to spend a year or two to achieve

This invention is a milestone in laser technology, and in the medical field, it can be used for bloodless surgery, eye care and dentistry. In the industrial field, it can help with cutting and welding. In the field of communications, it will greatly promote the development of optical fiber communications. ^[2]