Types of Laser and Laser Light Formation

Types of Laser and Laser Light Formation 

Principle:

The principle of laser operation is based on the stimulated emission of photons, which is the process of releasing light energy by an atom or molecule that has previously absorbed energy in the form of light or heat. When an external energy source, such as an electrical current or another light source, is used to excite atoms or molecules within a laser medium, some are raised to a higher energy level. These excited atoms can then release their extra energy as photons of light when they return to their original state.

The cavity of a laser is designed to reflect photons emitted by the excited atoms or molecules back and forth in a resonant manner, which leads to the stimulation of more emissions. Depending on the type of laser, this cavity can consist of mirrors or fibers that keep the photons confined and aligned in a specific direction, forming a coherent beam of light. The energy of the photons emitted by the stimulated emission process is focused and concentrated into a highly directional, monochromatic, and coherent beam that can be used for a wide range of applications, including in science, medicine, industry, and communications.

 Laser Light Formation

Laser light is formed by the following phenomena

1. Active medium ( ground state)

2. Excited state ( pumping)

3. Metastable state ( increase time of excited state)

4. Population inversion ( more atoms in the excited state)

5. De excitation ( emission of a photon by using an external source, Stimulated emission)

6. Amplification

7. Laser light emission 

Laser Light Formation

Types of Laser 

There are several types of lasers, including:

1. Gas lasers: 

These use a gas mixture as the active medium, such as helium-neon (He-Ne) lasers and carbon dioxide (CO2) lasers.

2. Solid-state lasers: 

These use a solid material as the active medium, such as neodymium-doped yttrium aluminum garnet (Nd: YAG) lasers and ruby lasers.

3. Semiconductor lasers:

These use a semiconductor material as the active medium, such as diode lasers and quantum cascade lasers.

4. Fiber lasers: 

These use glass fibers as the active medium, such as ytterbium-doped fiber lasers and erbium-doped fiber lasers.

5. Excimer lasers: 

These use a combination of gases, such as xenon and chlorine, to produce laser light for short pulses in a high-energy ultraviolet wavelength.

6. Dye lasers: 

These use organic dyes as the active medium and are typically used for research and medical applications.

7. Free electron lasers: 

These use a beam of accelerated electrons to produce laser light.

8. Chemical lasers: 

These use chemical reactions to produce laser light, such as hydrogen fluoride lasers and deuterium fluoride lasers.

Applications of Laser in Various Fields 

Laser technology has had a significant impact on various fields, including the medical field. Here are some ways in which lasers are used by humans in the medical field and other industries:

1. Surgery: 

Lasers are widely used in surgical procedures, both minimally invasive and traditional open surgeries. They can precisely cut or vaporize tissues, minimizing bleeding and reducing the risk of complications. Laser surgery is commonly used in fields like ophthalmology, dermatology, gynecology, neurosurgery, and various other specialties.

2. Dermatology and Cosmetology: 

Lasers are extensively used in dermatology and cosmetology to treat various skin conditions. They can remove scars, wrinkles, tattoos, birthmarks, and unwanted hair. Laser skin resurfacing is also used for rejuvenation and treatment of aging signs.

3. Dentistry:

 Dental lasers find applications in various dental procedures. They can be used to remove decayed tooth material, shape teeth for fillings or crowns, perform gum surgeries, and treat gum diseases. Laser dentistry is known for less pain and faster healing compared to traditional techniques.

4. Eye Surgery: 

In ophthalmology, lasers play a crucial role in vision correction procedures such as LASIK (laser-assisted in situ keratomileusis) and PRK (photorefractive keratectomy). These procedures reshape the cornea to correct nearsightedness, farsightedness, and astigmatism.

5. Cancer Treatment: 

Laser technology is utilized in certain cancer treatments like laser ablation or photodynamic therapy (PDT). In PDT, a photosensitizing drug is introduced into the body, and a laser is used to activate this drug, specifically targeting and destroying cancer cells.

6. Endoscopy:

Lasers find applications in endoscopic procedures, allowing doctors to visualize and treat conditions in the gastrointestinal tract, urinary tract, respiratory system, and other body cavities. Laser endoscopy can surgically remove polyps, cauterize bleeding vessels, or treat strictures without major incisions.

7. Industrial and Manufacturing: 

Lasers are extensively used in industries like manufacturing, material processing, and quality control. They can cut, weld, drill, mark, and engrave metals, plastics, fabrics, and other materials with high precision. Lasers are also used in measuring and inspecting manufactured components.

Overall, lasers have revolutionized many aspects of medicine and various industries, offering precise and effective solutions in a wide range of applications.

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Laser Phenomenon, Working and properties