What is the Function of Laser Collimating Lens?

Semiconductor lasers have the advantages of low cost, long life, small size, and high reliability, and have broad application prospects in industrial processing, pumping, medical treatment, and communications. Whether the laser output brightness can be further improved is an important factor restricting the future development of semiconductor lasers. The brightness of the laser beam is determined by the output power and beam quality. The higher the power, the better the beam quality and the higher the brightness. The application field of semiconductor lasers is also wider.

1. Application of collimating lens in semiconductor laser

Semiconductor laser array is one of the common means to realize high-power, high-brightness semiconductor laser. The semiconductor laser array arranges a plurality of semiconductor laser light-emitting units in sequence in the slow axis direction to realize the accumulation of power. The divergence angle of a single light-emitting unit in the fast axis direction is usually 30 to 40°, and the divergence angle in the slow axis direction is usually 5° to 10°. In practical applications, the fast and slow axes need to be collimated. At present, the commonly used collimation method is to use the fast-axis collimating lens and the slow-axis collimating lens respectively, first let the light beam pass through the fast-axis collimating lens (usually an aspheric cylindrical lens), and then let the light beam pass through the slow-axis collimating lens ( Usually a micro-cylindrical lens array) to obtain a collimated laser beam array.

2. The role of laser collimation lens

Laser collimating lens is one of the core accessories of laser equipment such as laser welding machine, laser marking machine, laser cutting machine, laser engraving machine, etc. The collimating lens is for point light source, and the laser collimating lens is from energy fiber. The light, that is, a point light source with a divergence angle, is placed at the focal point of the fiber collimating lens, and the light emitted from the focal point of the focusing lens will become parallel light after passing through the collimating lens.

Laser collimating lenses are used in various optical measurement systems, and are often used to collimate the optical path, so that the divergent optical path becomes a parallel optical path. With different optics, beam collimation can be optimized for different measurement processes. In order to improve the fiber coupling efficiency and reduce the beam divergence angle, a fiber collimating lens needs to be installed at the fiber port.

After passing through the collimating lens, the area of the focused spot is twice as large as the area of the point light source that just came out of the energy fiber, the energy density is 1/2 of the original, and the beam collimation degree is high. After adjustment by the fiber collimating lens , the divergence angle of the beam does not exceed 2°. The function of the laser collimation lens of the CO2 laser is to install it in the laser head to focus the laser beam. When installing, the convex surface is upwards to ensure that the lens is installed firmly and not loose.