Terahertz waves, also known as the "frequency of dreams," have been gaining attention in recent years due to their potential applications in various fields. According to the Electronics and Telecommunications Research Institute (ETRI), electromagnetic waves used for communication and light waves from the sun are essentially the same. They are all electrical waves, known as electromagnetic waves, which are categorized as radio waves, microwaves, and light waves based on their frequency bands. Radio waves and microwaves are low-frequency electromagnetic waves used in radio and similar technologies. Light waves, on the other hand, are high-frequency electromagnetic waves used in medical imaging and astronomy.
Telecommunications engineers have explored higher frequency bands for communication, while optical engineers have focused on lower frequency bands of light. However, there is an area that was not well known until recently - the "terahertz wave" section. Terahertz waves vibrate 1,000 times faster than the frequency used in 5G, which has the highest frequency among communication frequencies, and 100 times slower than infrared rays, which have the lowest frequency among light waves. It is an electromagnetic wave that belongs to the middle region between light and radio waves for communication.
Early research on terahertz waves began in the field of astronomical observation in the 1920s, but it was only in the past 20 to 30 years that scientists began researching and developing terahertz waves in earnest. This was because terahertz waves are easily absorbed by water, which made it difficult to apply them to everyday life using past technologies.
Currently, laboratory technology that generates terahertz waves and uses them to detect substances is being actively developed. Scientists are working to create a technology that fully utilizes the characteristics of terahertz waves, which have several unique features.
First, terahertz waves can penetrate opaque objects such as cloth or boxes, and are reflected when they meet metal. They are safe for the body as the energy is low enough to avoid damaging living tissue or DNA. Using this feature, security screening can be performed with terahertz waves instead of X-rays, which cannot be used directly on people in the departure hall.
Second, terahertz waves can easily distinguish objects with different components. It is possible to use the principle of absorbing different amounts of terahertz waves for each material. For example, flour and white dope appear as different colors in a camera that shoots terahertz waves, even though they look similar to the naked eye. This makes it possible to simply inspect the components of matter through terahertz waves.
Third, terahertz waves are easily absorbed by moisture. By using the weakness of terahertz waves, which are vulnerable to moisture, it is possible to check the moisture content of the test target. This can be applied to quality inspection, such as finding products with different moisture content in food factories. It can also be used for medical purposes, as cancer cells contain more water than normal cells. Therefore, the location of cancer cells can be tracked by taking images with terahertz waves.
Terahertz waves have been called the "dream frequency" because they can transmit more information than existing wireless communication frequencies, can be used for detecting drugs or harmful gases, and can also be applied to medical diagnostic technology. It will not be long before we encounter terahertz wave technology with such wide applicability in everyday life. The advent of new terahertz waves is expected to make our lives more convenient, and we look forward to that future.
