MWIR zoom system.

This project presents an original optical design of a 20× continuous zoom lens operating in the Mid-Wave Infrared (MWIR) region, covering a focal length range of 15 mm to 300 mm at a constant F-number of 3.6.

The optical system was developed entirely from scratch, without using any existing or patented optical design as its starting point. The design was optimized to maintain consistent imaging performance throughout the entire zoom range, rather than focusing only on selected focal length configurations.

Particular attention was given to athermalization, narcissus suppression, and zoom compensation, ensuring consistent optical behavior as the system transitions from wide-angle to narrow-angle operation.

The 15–300 mm F/3.6 MWIR zoom lens was developed entirely from scratch, without using an existing or patented optical design as the starting point. The system was optimized to achieve the best possible imaging performance across the full 20× continuous zoom range.

The zoom mechanism consists of two moving groups: a two-element variator and a single-element compensator. Particular attention was given to maintaining consistent zoom trajectories and achieving stable optical performance throughout the focal length range.

During the initial optimization, the system achieved its best imaging performance, but narcissus performance remained unsatisfactory. The design was subsequently re-optimized to reduce narcissus effects, accepting a small degradation in conventional imaging performance to achieve a more balanced overall system design.

Athermalization was also incorporated to control temperature-induced focus shifts and maintain performance over the intended operating temperature range. The final design reflects a balanced optimization approach that considers image quality, narcissus, thermal stability, and zoom mechanism behavior together.