Lasers are used to produce a captivating technology “hologram”. A hologram consists of a piece of film on which an interference pattern results in a three-dimensional image of an object. Unlike traditional photographs or paintings, which are two-dimensional, holograms provide depth, allowing us to see an object from different angles as if it were right in front of us. This incredible technology can create lifelike images that may be familiar to you through their appearance on magazine covers or baseball cards. Optical fibers are thin flexible glass wires that can transmit light over long distances.  In this article, we will learn about the hologram, how hologram works, and the other uses of laser and fiber optics.

Interference occurs when two or more waves overlap, creating regions of increased or decreased amplitude. In the case of holography, two beams of light are used: a reference beam and an object beam.

To create a hologram, a laser beam is split into two parts. One part serves as the reference beam, and the other is directed at the object being recorded. When the object beam strikes the object, it scatters in various directions and interacts with the object's surface. This interaction causes the light waves to carry information about the object's shape and texture.

The object beam and the reference beam converge onto a photosensitive plate or film. When they meet, they create an interference pattern on the recording medium. This pattern contains all the information needed to reconstruct the three-dimensional image.

To view the hologram, a laser beam similar to the reference beam is directed onto the developed holographic plate. When this laser beam illuminates the interference pattern, it causes the scattered light to reconstruct the original object's shape and appearance. The viewer perceives the holographic image as if it were a real, three-dimensional object.

Holograms, like the one shown in the mentioned Figure 2, are similar to photographs because they are images permanently recorded on film. Unlike traditional photographs where the image is on the film's surface, holograms create the illusion that the image exists either in front of or behind the film. Moreover, a distinctive feature of holograms is their ability to change perspective when the observer shifts their viewpoint, allowing you to see the image from various angles.

In addition to making holograms, lasers are used for a variety of tasks. For instance, lasers serve as proficient cutting tools, effectively slicing through materials like metal and fabric. In the field of medicine, surgeons employ lasers for delicate procedures involving human tissue, including vision-correcting surgeries on the cornea for conditions like nearsightedness and farsightedness. Furthermore, lasers can also be used as extremely accurate rulers. Lasers play a crucial role in the playback of music from CD players.

Imagine a slender glass thread, as fine as a human hair that can transmit more than 1,000 telephone conversations at the same time using nothing but only flashes of light. While this may sound impossible, but such glass threads are working all over the world. These threads are known as optical fibers.

Optical fibers are thin flexible glass wires that can transmit light over long distances. A visual representation of optical fibers is shown in the mentioned figure. The use of optical fibers is known as fiber optics, a technology that has found its most widespread application in revolutionizing telecommunications.

The most common use of optical fiber is the transmission of information through telephone cables. Optical fibers offer a multitude of advantages such as they carry information faster and more clearly than older copper telephone cables. Beyond telecommunications, optical fibers are also used to network computers and to allow doctors to see inside patients’ bodies without performing major surgery.

Optical fibers transmit light over long distances because they act like pipes for light. Just as a well-constructed water pipe doesn’t let water leak out, a good light pipe doesn’t let light leak out. The mechanism that keeps the light securely within the optical fiber is known as total internal reflection. Total internal reflection is typically the complete reflection of light along the inside surface of the medium through which it travels. The mentioned figure shows the total internal reflection in an optical fiber.