Infrared imaging has been vigorously pursed in parallel with visible imaging because of its utility in military applications.

Some of these early developments were intended for a picturephone, other efforts were for television cameras, satellite surveillance, and digital imaging. Photolithography enabled the fabrication of silicon monolithic imaging focal planes for the visible spectrum beginning in the early 1960s. Zworykin and Morton, the celebrated fathers of videonics, on the last page of their legendary book Television (1939) concluded that: вЂњ when rockets will fly to the moon and to other celestial bodies, the first images we will see of them will be those taken by camera tubes, which will open to mankind new horizons.вЂќ Their foresight became a reality with the Apollo and Explorer missions. Applications and new devices soon flourished, pushed by the dawning technology of vacuum tube sensors developed in the 1920s and 1930s culminating in the advent of television. Progress was slow until 1905, when Einstein explained the newly observed photoelectric effect in metals, and Planck solved the blackbody emission puzzle by introducing the quanta hypothesis. The birth of photodetectors can be dated back to 1873 when Smith discovered photoconductivity in selenium. Looking back over the past several hundreds of years we notice that following the invention and evolution of optical systems (telescopes, microscopes, eyeglasses, cameras, etc.) the optical image was formed on the human retina, photographic plate, or films. 1) is often described as the final unexplored area of spectrum and still presents a challenge for both electronic and photonic technologies. The terahertz (THZ) region of electromagnetic spectrum (see Fig. Radio (1886вЂ“1895), X-rays (1895), UV radiation (1901), and radar (1936) were invented in the end of the 19-th and the beginning of the 20-th centuries. Candles appeared around 1000 BC, followed by gas lighting (1772), and incandescent bulbs (Edison, 1897). Cave men used torches (approximately 500,000 years ago). First humans relied on the radiation from the Sun. Finally, the outlook for near-future trends in optical detector technologies is presented.Дevelopments in source and detection of electromagnetic radiation have a very long history. Emphasis is also given on far-infrared and sub-millimetre wave detector arrays. Discussion is focused mainly on current and the most rapidly developing focal plane arrays including: CdZnTe detectors, AlGaN photodiodes, visible CCD and CMOS imaging systems, HgCdTe heterostructure photodiodes, quantum well AlGaAs/GaAs photoresistors, and thermal detectors. Special attention is given on recent progress in their detector technologies. The main subject of paper is concentrated on describing of material systems and detectors operated in different spectral ranges. This topic is followed by general overview of focal plane array architectures. Next, the classification of two types of detectors (photon detectors and thermal detectors) is done on the basis of their principle of operation. At the beginning of paper, emphasises are given on integrated detector assembly and cooling requirements of different types of detectors. This paper presents progress in optical detector technology of focal plane arrays during the past twenty years. Development of focal plane arrays started in seventies last century and has revolutionized imaging systems in the next decades.

Gundlach radar extreme wide angle lens