<title>Analysis on optical dome in wider waveband</title>

Abstract

ABSTRACT Optical sensors airborne will include a laser rangefinder, an infrared search and tracking system (IRST) or forwardlooking infrared system (FLI ) , as well as a visible TV system and image intensifier. these optical systems areequipped in varying conditions where the environment is very different. They must be capable of withstanding theharsh land, air and sea environments associated with military operations, such as impact from airborne sand, grit, insectand raindrops. In order to solve the questions, a wider spectral band dome is often used for protecting the opticalsystem.This paper will describe mainly a hemispherical dome a irborne and analyze the effect of mater ial and shape of domeon imaging performance. The improvement design will be discussed finally. Keywords: hemispherical dome, multispectral materials,1. INTRODUCTION New reconnaissance system airborne requires to achieve multiple functions and higher degree of accuracy. Thirequirement has led to the development of new sensor/detector technologies from visible light to midwave infrared(MWIR) light, even to far wave infrared (FWIR) light. In general, The optical systems airborne include a laserrangefinder, an infrared search and tracking system (IRST) or forward looking infrared system (FLI ) , a visible TVcamera system as well as image intensifier. They operate in a wider spectral region, for example, laser rangefinder andIRST system on aircraft are used at the same time. Here, the wavelength of laser rangefinder is 1.06µm or 1.5 4µm andthe wavelength of IRST is 3 5 m. Perhaps, visible CCD camera (0.4 0.7 m), image intensifier operating in the0.6 1.0 m band and FWIR wavelength(8 14 m) will be used in the same device. The infrared imaging system is a critical component of military aircraft operations for navigation, surveillance andtarget acquisition. Generally speaking, optical materials with high optical transparency in the IR imaging system havelow hardness and poor mechanical strength. In addition, these optical systems are equipped in varying c onditions wherethe environment is very different. They must be capable of withstanding the harsh land, air and sea environmentsassociated with military operations, such as impact from airborne sand, grit, insect and raindrops. In order to solve thequestions, a wider spectral band dome or window is often used for protecting the optical system from the environment,tominimize the performance degradation and boresight wander [1]. A dome or window for an electro-optical equipment, either aircraft or missile dome, serves two functions mainly:(1) to protect the optical system from the poor environments;(2) to meet the aerodynamic requirements.