A laser is created when electrons in the atoms in optical materials like glass, crystal, or gas absorb the energy from an electrical current or a light. That extra energy “excites” the electrons enough to move from a lower-energy orbit to a higher-energy orbit around the atom's nucleus.
A laser is a device that produces a narrow beam of light in which all of the light waves have very similar wavelengths. The key to understanding how a laser works lies in how the light waves are aligned and synchronized.
Inside a laser, there is a material called a "lasing medium" that can absorb energy and release it as light. The lasing medium is usually in the form of a crystal or a gas. When energy is supplied to the lasing medium, it becomes "excited" and the atoms within it enter a higher energy state.
The next step is when the atoms in the lasing medium release the excess energy, known as "stimulated emission." This release of energy triggers other atoms to release their energy as well, resulting in a cascade effect. The released energy propagates in the form of photons, which are particles of light.
What sets a laser apart from ordinary light sources is the process of "stimulated emission." In a laser, the released photons travel in the same direction and have the same wavelength. They are all "in phase," meaning that their peaks and troughs align with each other. This coherence of light waves allows the laser beam to be very focused and concentrated in a narrow beam.
The aligned photons bounce back and forth between two mirrors placed at opposite ends of the lasing medium, which further amplifies the light. One of the mirrors is partially transparent, allowing a small portion of the light to pass through and form the laser beam that we see.
To summarize, a laser works by exciting atoms in a lasing medium and causing them to release photons through stimulated emission. The released photons have the same wavelength and travel in the same direction, resulting in a concentrated beam of coherent light.A laser, which stands for "Light Amplification by Stimulated Emission of Radiation," is a device that produces a highly concentrated beam of light. This concentrated beam of light is created through a process called stimulated emission.
Inside a laser, there are three main components: an energy source, a gain medium, and mirrors. The energy source, which could be an electric current or a flash lamp, supplies energy to the gain medium.
The gain medium is a material that can absorb energy and then release it as light. It is usually made of a crystal, gas, or semiconductor material. When energy is supplied to the gain medium, some of its atoms or molecules get excited, moving to a higher energy state.
As these excited atoms or molecules return to their lower energy state, they emit light. This emission of light is called spontaneous emission. However, in a laser, we want the light to be highly concentrated and coherent (in-phase).
To achieve this, the mirrors at each end of the gain medium are used. One mirror is partially reflective, allowing some light to escape, while the other mirror is fully reflective, reflecting all the light back into the gain medium.
When the emitted light photons travel back and forth between the mirrors, they stimulate other excited atoms or molecules to emit more photons. This process is called stimulated emission, and it results in a chain reaction, producing a concentrated beam of light.
The photons in the laser beam are all in-phase and have the same wavelength, making the beam very bright and focused. The properties of lasers, such as their narrowness, high intensity, and ability to be focused into a small spot, make them useful in various applications like communications, cutting, welding, medical procedures, and many more.