Laser seeker design with multi-focal diffractive lens

Abstract Diffractive optical elements are increasingly favoured due to their ability to provide numerous design freedoms by adjusting the Fresnel regions. The design freedoms make it possible to meet multiple system functions in electro-optical systems simultaneously by using a single optical element. This research introduces a novel laser seeker design with a multi-focal diffractive lens that enhances a laser seeker’s measurement sensitivity and linear measurement range. The development of the multi-focal combined lens, featuring two distinct regions with unique focal lengths, aims to simultaneously fulfill two system functions within the laser seeker. The central region of the lens is intended for adjusting the linear measurement range, while the outer region is utilized to regulate the measurement sensitivity of the seeker. The numerical optical wave propagation method was employed to simulate the behaviour of the laser seeker with a multi-focal diffractive lens, and the combined diffractive lens was compared to an ideal lens in the scope of laser seeker application. The simulation results indicate that the measurement sensitivity of the seeker has been increased between 0° to ±3° angular incidence, and the linear measurement range has been increased from ±18° to ±26°. The findings of this study contribute to the advancement of multi-focal diffractive lenses, which fulfil multiple functions within an electro-optical system concurrently.