This two-mirror optical system adopts a reflective afocal structure design, consisting of a primary mirror and a secondary mirror to form a coaxial optical assembly, featuring high imaging quality, high stability and low distortion. The system is compact in structure and strong in stray light suppression, suitable for applications such as laser collimation, beam shaping and long-distance transmission. The integrated mechanical structure integrates mounting interfaces and adjustment mechanisms, enabling high-precision alignment and long-term stable operation, meeting the requirements of scientific research, industrial inspection and optoelectronic system integration.

Two-mirror system, or dual-reflector optical system, takes a primary mirror and a secondary mirror as the core imaging/collimation structure. It is a classic design for high-resolution, achromatic, large-aperture optical systems, widely used in astronomical telescopes, lidar, deep-space exploration, precision measurement and industrial optical lenses. ### I. Basic Structure and Principle Primary mirror: usually parabolic / hyperbolic / ellipsoidal, collects light and reflects it to the secondary mirror. Secondary mirror: placed in front of the primary mirror, reflects light again to fold the optical path and shorten the overall system length. Core advantages: - Fully achromatic (reflection is wavelength-independent), suitable for broadband and multi-band applications. - Folded optical path, system length much shorter than focal length, compact structure. - Large aperture and lightweight, beneficial for high light-gathering capability and high resolution. ### II. Classic Types of Two-Mirror Systems Newtonian system Parabolic primary mirror + flat secondary mirror Simple structure, low aberration, mostly for astronomical observation. Cassegrain system (most widely used) Parabolic primary mirror + hyperbolic secondary mirror Long focal length, short barrel, high imaging quality, mainstream for telescopes, remote sensing and spotting scopes. Ritchey-Chrétien system (R-C) Hyperbolic primary mirror + hyperbolic secondary mirror Wide field of view, extremely low off-axis aberration, preferred for professional astronomy, space telescopes and high-resolution remote sensing. ### III. Key Features Achromatic and broadband: compatible with visible, infrared and ultraviolet spectra. Large aperture and high resolution: lighter and more capable than refractive lenses at the same aperture. Compact structure: ideal for precision instruments with limited space. Easy coating, high reflectivity: outstanding advantages in laser and weak-light detection. ### IV. Typical Applications Astronomical telescopes, space observation cameras Lidar, laser collimation, beam shaping Remote sensing satellites, aerial surveying High-precision measuring instruments, infrared imaging systems Industrial lenses, long-distance monitoring, targeting optics