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Laser Technology

For years the lasers have been the hallmark of science fiction. Yet much of our technology today depends on them like range finding devices, optical communications & bar-code scanners, etc. The unique characteristics of laser light make all these things possible.

How a laser creates light

You have seen most of the glowing toys in the dark. These toys glow because the zinc copper-based compound coating the inside can absorb energy from the light source & later radiate as light. The light provides energy to electrons & the coating promotes them to higher energy levels. Once the light is off, these electrons slowly lose their added energy & return to their lower energy ground states. Moreover, the energy lost is given off as light. Unlike the glow in a dark ball, the light appears immediately.

How laser works

Laser light concept: A flash would promote a few electrons from the ground state to an excited state. They lose a bit of energy fall to a lower energy state without emitting light & then dropped from there to the ground state giving off a burst of light. The light produced would be incoherent in the spectrum of color & intensities. As to create a laser, it takes an extremely powerful lamp. They supply so much energy that a population inversion occurs. The electrons from the population inversion returning to the ground state release light that starts an avalanche known as stimulated emission. The photon produces when the electron decays induce other excited electrons to simultaneously decay & release nearly identical photons that create coherent light.

Laser Beam

To get a narrow beam with all the light rays parallel & of a nearly single wavelength requires an addition to the ruby rod. Mirror silvered reflects the light within the ruby cylinder. As it made the two end of the rod astonishingly parallel to each other. From the top to bottom the distance between 2 mirrors differs by no more than 200 nanometers. Inside this resonant cavity, 2 things happen.

1. Any light rays that don’t line up with the axis eventually just exit out the side of the cylinder.
2. The light parallel to the axis becomes intensified & narrowed in wavelength.

The mirrored ends create a standing wave which means only light of particular wavelengths can exist inside the cavity. By choosing the rod length correctly, we can get the nearly single wavelength of light characteristic of a laser. A small hole in one of the mirrors where a partially silvered mirror allows the light to escape creating the familiar beam. Nowadays, lasers have become easy & cheap to manufacture.

Read Similar: How do solar panels work and how solar panels are made

High power laser pointer experiment [Video]

Laser pointer explained

The laser pointer uses a semiconductor diode to produce light. Although many innovations & improvements have occurred. Since 1960 the essential principles are the same. The term NM describes the color of the laser & wavelength is what color your laser is. Many lasers have different wavelengths meaning that they have different colors & NM is the unit of measurement that we used to measure wavelengths. Moreover, the letter NM stands for nanometer, it’s one billionth of the meter. So it’s an extremely tiny unit of measurement & all light is essentially an electromagnetic wave.