Using laser pointer to turn the light beam into intense monochromatic radiation has completely changed the way we live and work, and has a history of more than 50 years. Its many applications include: ultra-fast and high-throughput data communications, manufacturing, surgery, barcode scanners, printers, driverless technology, and laser projection displays. Lasers are also used in atomic and molecular spectroscopy, and can be used for the detection and analysis of various scientific branches and various chemical substances and biological molecules.
Lasers can be classified according to their emission wavelengths in the electromagnetic spectrum. Visible lasers such as laser pointers are only a small part of them. Infrared lasers can be used for optical communication through optical fibers; ultraviolet lasers can be used for ophthalmic surgery; there is also a terahertz laser, which is also the subject of research by Sushil Kumar's research team, Lehigh University School of Electronics and Computer Engineering.
In the electromagnetic spectrum, the radiation emitted by a terahertz laser is located between microwave and infrared light. Its radiation can penetrate common packaging materials such as plastic, fiber fabric and cardboard, and it is also very effective for optical sensing and analysis of various chemical substances. This type of laser (terahertz laser) has broad application prospects and can be used for non-destructive screening and detection of packaged explosives and illegal drugs, evaluation of pharmaceutical compounds, screening of skin cancer, and even research on the formation of stars and galaxies .
Applications such as spectroscopy require laser pointer to emit at precise wavelengths, which is usually achieved through a technique called distributed-feedback. Such devices that emit precise wavelengths are called single-mode lasers. Since the most important application of terahertz lasers will be in terahertz spectroscopy, the requirement for single-mode operation is particularly important for terahertz lasers. Terahertz lasers are still in development and researchers around the world are trying to improve their performance characteristics to make them commercially viable.
Terahertz radiation is absorbed by atmospheric humidity as it propagates. Therefore, the key requirement is that such lasers must be powerful enough to be used for optical sensing and material analysis at distances of several meters or more without being absorbed. To this end, Kumar's research team focuses on increasing the intensity and brightness of the laser, which can be achieved to some extent by increasing the optical power output.