Electricity is an essential element of modern society and is utilized in a variety of fields. Among the various careers in the Department of Electrical and Computer Engineering, lasers, a core technology in the field of electronics, play an important role in many industries and have great potential for development in the future. We will explore the principles and applications of lasers, as well as discuss their technological limitations and challenges.
Electricity has become indispensable in the modern world. Not only is it used for physiological needs such as darkness, cold, and heat, but it is also indispensable for transportation, communication, and recording. Electricity doesn’t just fulfill our everyday needs, it plays an important role in the economy and industry as a whole. For example, the development of advanced technologies such as industrial robots, electric vehicles, and smart grids all rely on a reliable supply of electricity. In this context, electrical and information engineering is positioned as a key technology that will drive the future of society, and the applications of electricity are endless. Therefore, there are countless career paths in the Department of Electrical and Information Engineering.
The majors, or sub-majors, of E&I are broadly divided into the system field, electronics field, and computer field. The systems field deals with large-scale systems that run on electricity. Signal analysis and communication, networks, power transmission and reception, market analysis, control engineering, etc. fall under the system field. This field is particularly important for the maintenance and development of national infrastructure and is becoming increasingly important for large-scale projects such as smart cities. Electronics, on the other hand, is smaller and more detailed. Analog and digital circuits, nanodevices, and their integration into biotechnology are all covered in electronics. This field provides the core technology for the smartphones, wearables, and medical devices we use every day. Computer science literally means the study of computers, and in electrical engineering, the focus is more on hardware. This is somewhat different from computer science, which emphasizes software. Maximizing the efficiency of hardware and developing new structures are important areas of research in electrical and information engineering. Because of this diversity, undergraduate courses focus on basic education that is common to many fields so that students can easily adapt to any field.
In this introduction to the major, we will focus on lasers in the field of electronics. A laser is a device that continuously emits light of the same wavelength and phase. I chose lasers as the subject of this article because they are very technology-intensive, but they are also very familiar to the public. Today, lasers are used in a variety of fields, including healthcare, communications, and entertainment. For example, lasers are used in eye surgery to speed up recovery time for patients, in telecommunications to dramatically increase data transmission speeds, and in entertainment, such as laser shows, they’ve become a part of our lives.
Lasers utilize the phenomenon that atoms in an excited state emit light when they change to a stable state. However, the light emitted in the natural state is of different phases and wavelengths, and does not travel far. However, if you create a situation where the excited atom is hit by light of the same wavelength as the light it emits, the excited atom will emit light of the same wavelength, phase, and direction as the light it hit. This is called induced emission, and lasers are a dramatic example of induced emission.
A simple laser is made by placing an oscillating material inside a tube and attaching mirrors to each end. When a switch is flipped, a specific wavelength of light is emitted from the oscillating material. As this light is reflected through the mirrors, it collides with other emitting materials and becomes stronger through induced emission. This process is repeated hundreds or thousands of times inside the tube, and then the light passes through the mirror and becomes visible to our eyes.
Red lasers are common in everyday life. However, it’s rare to find lasers of other colors. This is because the color of the laser has to do with the oscillating material that is pre-charged to produce the light. The energy of atoms is quantized, meaning that they can only emit certain wavelengths of light. To make a laser of a desired color, you need to find atoms that emit light of the right wavelength, they need to be easy to keep excited, and they need to be inexpensive to commercialize. It’s hard to find an oscillating material that meets all of these requirements, which is why laser pointers are currently available in only a limited number of colors.
In the case of LEDs, which have recently gained attention as a light source, a wide range of colors are already commercially available. However, compared to the development era of LEDs, it has been time-consuming to construct a screen with full LEDs. In order to make a screen with full LEDs, it was necessary to realize and commercialize a blue-colored LED, and Japanese scientists who solved this problem were awarded the Nobel Prize in Physics in 2014. If we can develop and commercialize lasers of various colors like LEDs, we can also look forward to the Nobel Prize.
Another problem with lasers is their use in weapons. Of course, war is not good and shouldn’t be, but countries acknowledge this and are trying to strengthen their defense. If lasers themselves could be used as a weapon, wouldn’t it be great for defense to intercept incoming objects, or even mounted on airplanes to bomb them?
However, this is a difficult idea, because to attack, you need to use high-energy light, which loses energy as it travels through the atmosphere. As the high-powered laser collides with the air molecules, it turns them into plasma and loses its own energy and direction of travel. This phenomenon is called blooming, and laser shows in the atmosphere utilize it. Even if a high-powered laser hits a target without losing much energy, the cloud of particles created by the evaporation of the material at the point of impact will scatter the laser and make it ineffective as a weapon.
In this article, we learned what lasers are, their properties, and characteristics. Lasers are a mixture of optics and quantum mechanics, and can be described as a field that combines physics and electrical engineering. Laser technology has a wide range of potential applications in the future, which could lead to new industrial innovations. If you are interested in learning more about lasers, you can refer to the Introduction to Quantum Mechanics and Optoelectronics courses in the School of Electrical and Computer Engineering. It is also an exciting challenge to explore new possibilities of lasers through the convergence of various disciplines.
