1、 Working principle of collimating lens

The core function of a collimating lens is to adjust the direction of beam propagation through the principle of refraction. When a diverging light source (such as a laser diode or fiber optic output light) passes through a lens, the curved surface design of the lens will redistribute the propagation path of the light, making the light rays tend to be parallel. This process depends on the focal length and curvature radius of the lens:

Focal length selection: The shorter the focal length, the stronger the lens's ability to compress the divergence angle of the beam, but a too short focal length may lead to aberration problems.

Material characteristics: common materials include fused silica (high temperature resistance, low expansion coefficient) and optical glass (low cost), and infrared materials such as calcium fluoride (CaF ₂) can be used in special scenarios.

Coating technology: Anti reflective coatings can reduce surface reflection losses and increase light transmittance to over 99%, while customized coatings can also adapt to UV or infrared band requirements.

2、 Typical application areas of collimating lenses

Laser Processing and Manufacturing

In laser cutting, welding, and 3D printing, collimating lenses are used to ensure high energy density and parallelism of the laser beam, reducing processing errors. For example, the light output from a fiber laser needs to be calibrated through a collimating lens and then processed with micrometer level precision through a focusing lens.

Fiber optic communication system

Optical signals are prone to divergence in fiber optic transmission due to bending or connector issues. Collimator lenses can repair beam quality and improve the stability of long-distance transmission. In addition, it plays a key role in coupling optical paths in optical modules, such as the optical transceiver of 5G base stations.

Medical and Biological Imaging

Endoscopes, confocal microscopes, and other equipment rely on collimating lenses to control the illumination path and ensure imaging clarity. Laser medical equipment (such as ophthalmic surgery) also requires precise control of its range of action through collimation technology.

Research and testing instruments

In precision instruments such as spectrometers and interferometers, collimating lenses are used to calibrate light sources and avoid stray light interference with experimental results. In the field of autonomous driving, LiDAR systems achieve high-resolution ranging through collimated laser pulses.

3、 Selection and usage suggestions for collimating lenses

Key parameter matching

Wavelength range: It needs to match the wavelength of the light source, with significant differences in lens design for ultraviolet (200-400nm), visible light (400-700nm), or infrared (above 700nm).

Aperture: The aperture should be larger than the beam diameter to avoid edge light loss.

Surface accuracy: High precision applications (such as aerospace optics) require surface roughness<5nm, which can be relaxed to λ/4 (λ=633nm) in ordinary industrial scenarios.

Environmental adaptability considerations

In high temperature, high humidity or corrosive environments, quartz material+waterproof coating is preferred.

Scenes with frequent vibrations require seismic brackets to prevent lens displacement.

Maintenance and Calibration

Regularly clean the mirror surface with a dust-free cotton swab dipped in ethanol to avoid scratching by hard objects.

Use an interferometer or collimator to test the performance of the lens and adjust the installation angle in a timely manner.

4、 Industry development trends and innovation directions

Metasurface Lens Technology

Nanostructured metasurface lenses (Metalens) can replace traditional curved lenses, achieve thinner and lighter designs, and maintain high performance over a wide wavelength range, with the potential for application in AR/VR devices.

Intelligent integration solution

By combining sensors and automatic adjustment algorithms, an adaptive collimation system is developed to compensate for optical path deviations caused by factors such as temperature and vibration in real time, meeting the flexible production requirements of Industry 4.0.

Cost optimization and domestic substitution

With the breakthrough of domestic optical processing technology, domestic collimating lenses have approached international standards in coating uniformity, consistency, and other indicators, with prices 30% -50% lower than imported products, promoting downstream industries to reduce costs and increase efficiency.

Conclusion

As the "beam commander" of modern optical systems, the technological advancement of collimating lenses is constantly expanding their application boundaries. From gigabit level fiber optic communication to quantum computing laboratories, from Face ID modules for smartphones to LiDAR for deep space detectors, their value is increasingly highlighted in the wave of digitization and intelligence. In the future, with the integration of new materials and processes, collimating lenses will unleash their potential in more fields and become the core growth point of the optical industry chain.