There are applications for lasers in several fields. There are a lot of ways in which a laser can be generated. There are a lot of lasers with different principles.
One way to achieve high energy efficiency is by using bound states in the continuum. These states describe waves that are in space but not in the real world. BICs can be achieved by carefully designing the geometry of a periodic structure.
Most of the BIC-based lasers can only emit a beam in a horizontal direction away from the device. The use of BIC lasers in applications where angling the beam is needed is hampered by this limitation.
A research team from NYCU in Taiwan has created a new BIC laser device that can be easily adjusted. Tien-Chang Lu is a professor in the Department of Photonics at NYCU.
One of the main reasons for the creation of this new laser was its potential use in lidar systems. Laser light scanning is done using mechanical or microelectromechanical mirrors, which are bulky, expensive, and unreliable in rugged road conditions. Many people are trying to build a solid-state lidar system that can eliminate mechanical mirrors but still have beam-steering capabilities.
There is a demand for beam steerability. The team designed a device geometry that produced Friedrich- Wintgen BIC. This type of BIC is derived from the fact that the states at energies far from the resonance energy are located in the same cavity as the states at resonance energy. The main condition to create FW-BIC is that the radiation coming from these resonances should interfere with each other in the far field so that their energy is trapped within the cavity. A perfect environment for reaching lasing conditions is provided by the FW-BIC laser device, which has a high Q factor and is tightly confined.
FW-BIC helps develop a laser. A one-dimensional suspended high-contrast grating structure gave rise to FW-BIC. Changing the geometry of this grating changed the direction of the beam. The property made it easy to change the emission angle.
The largest angle demonstrated for BIC lasers was from -40 to +40. This feature allows us to design a laser array with a field of view of up to 80. This would be great for solid-state lidar applications.
The proposed beam-steering solution is expected to achieve a higher power efficiency because it does not require external passive components to modify the emission angle. The proposed design would hopefully lead to the development of large-scale, high-resolution laser scanning systems.
The Tunable lasing direction in one-dimensional suspended high-contrast grating using bound states in the continuum is more information. There is a book titled "10117/1.AP.4.6.066004."
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