Scientists Develop New Method To Output High-power Mid-infrared Lasers

Recently, a group of scientists led by the Nanyang Technological University of Singapore (NTU Singapore) developed a new method, which can generate intense ultra-fast laser light, and is expected to create accurate equipment that can accelerate the "sniffing" of trace pollutants and harmful gases.
Currently, lasers in the infrared range have the ability to analyze a wide range of substances in the air in a matter of minutes, whether they are greenhouse gases, toxins, explosives, or gases relevant to human health.
Of these, high-powered mid-infrared lasers are particularly critical, supporting highly sensitive remote detection equipment that can safely detect even trace amounts of substances that may be difficult to detect under ordinary conditions.
However, current technologies for manufacturing such lasers face challenges. On the one hand, some of the methods require strict laboratory environments that do not tolerate any form of interference, such as vibration, temperature or humidity variations, which limits their application in real-world environments. On the other hand, while some methods are able to generate laser light in unstable environments, the intensity is not strong enough to accurately detect trace amounts of substances.
A research team from Nanyang Technological University in Singapore, led by Assistant Professor Chang Wonkeun, has successfully solved the above challenges by using a special hollow fiber and adjusting the thickness of its internal structure. The new method can generate high-brightness laser light in the mid-infrared range without relying on a stable laboratory environment.
Our technique provides a new way to develop portable, efficient and fast mid-infrared lasers," said Prof. Chang. These lasers do not need to be operated in a strictly controlled environment and can therefore be combined with detectors and used directly in the field to test and identify a wide range of unknown substances. This means that we no longer need to send samples to laboratories for testing, even for trace amounts of substances, saving significant time and resources."
Hollow fiber technology, which allows mid-infrared lasers (wavelengths of 2-20 microns) to demonstrate significant advantages when detecting substances. Many molecules have unique absorption properties for lasers in the mid-infrared range, making these lasers particularly effective in identifying unknown substances. In addition, the mid-infrared laser can accurately recognize substances even when water is present, without interference from water molecules.
Assistant Professor Chang Wonkeun discovered through computer simulations that by varying the wall thickness of hollow fiber microtubes, it is possible to convert near-infrared lasers into high-power mid-infrared lasers. The experimental results showed that they succeeded in creating mid-infrared lasers with a wavelength of 3-4 micrometers and a peak power of up to megawatts, far exceeding that of a standard light bulb.
Prof. ssambastien fsamvrier of the University of Limoges commented that the Nanyang Technological University team's approach is very different from the traditional complex nonlinear arrangement and provides a new way of thinking for fabricating stable mid-infrared lasers. In addition, since hollow fibers can be spliced with each other, this opens up the possibility of producing mid-infrared lasers without moving mechanical parts.
Experimental data show that the mid-infrared lasers fabricated by the team are about 1,000 times more powerful than existing techniques, and are powerful enough to detect trace substances over long distances.Prof. Chang further noted, "With such high intensity lasers, we can achieve unprecedented sensitivity and expect to use these devices to safely detect trace amounts of substances that are difficult to detect by conventional methods. substances that are difficult to detect by conventional methods."
The results of this research not only provide technical support for the development of more accurate environmental monitoring equipment, but may also play an important role in the field of health monitoring. For example, by detecting methane levels in breath, the technique could be used for early screening for colorectal cancer.
Looking ahead, the research team plans to further expand the wavelength range of the mid-infrared laser to improve its detection capability. According to Assistant Professor Zhang, the method can theoretically produce mid-infrared lasers with wavelengths up to 10 micrometers, which will further broaden its application in areas such as environmental monitoring and safety detection.