tailieunhanh - Advances in Lasers and Electro Optics Part 14

Tham khảo tài liệu 'advances in lasers and electro optics part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 27 Fundamentals and Applications of Quantum Limited Optical Imaging Warwick P. Bowen1 Magnus T. L. Hsu1 and Jian Wei Tay2 1School of Mathematics and Physics University of Queensland QLD 4072 2Physics Department University of Otago Dunedin 1Australia 2New Zealand 1. Introduction The field of optical imaging is focussed on techniques to extract useful information about a physical system from the spatial structure of light. There are two main themes to research in this field the resolving of previously unknown structures ranging in size from microns in microscopy to distant galaxies in astronomical telescopy or if the structure is selected from an a priori known set then its unique discrimination such as in data read-out from a CD or DVD. In general both types of imaging involve the collection and focusing of light after interaction with the object. However the process of information extraction can be quite different. In resolving an unknown structure a full two dimensional image is usually desired. Here the metric of success is generally the resolution of the final image. In most cases diffraction is the key concern presenting the diffraction limit to the resolution of the final image as approximated by Abbe Born Wolf 1999 . There are ways to overcome this limit such as by utilising non-linearities Hell et al. 2009 or using metamaterials Pendry 2000 to form so called superlenses and this is a vibrant and growing area of research. The focus of this Chapter however is on the second theme of imaging discrimination between a set of known structures. As we will see this form of imaging is important not only for read-out of information from data storage devices but also in other areas such as microscopy Fabre et al. 2000 Tay et al. 2009 and satellite navigation Arnon 1998 Nikulin et al. 2001 . In structure discrimination the goal is not to achieve a two dimensional image but rather to generate a signal which unambiguously distinguishes each element of the set. Hence the .

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