Studies Of Subwavelength Imaging And Focusing Using Metamaterials

The steadily decreasing dimensions in semiconductor devices are for filling the rapid development of the information technology, especially for the high-end nano-optical imaging technology. Subwavelength resolution is widely required in many fields, such as optical lithography, confocal microscopy, high-density optical storage, nano-laser processing, biological microscopy, life science, etc. However, traditional optical imaging techniques have been unable to meet the requirements for the diffraction limit. In this paper, based on the subwavelength super-resolution imaging technology-hyperlens, which can overcome the diffraction limit, and another resolution enhancement techniques-alternating phase shift mask (Alt-PSM), we propose a novel subdiffraction-limited photolithography design. Theoretical analysis and numerical simulation show that the combination of Alt-PSM and planar hyperlens can realize subwavelength plane-to-plane imaging beyond the diffraction limit. And in this paper, based on a new metamaterial, which is a new type of aritificial electromagnetic material or sturcture, and has electromagnetic properties that are not found in nature and can be artificially tuned at will, we also present a new structure of hyperlens called "trumpet hyperlens". It has a strong ability to focus over a broad wavelength range, and it will have important potential applications.Firstly, based on the analysis of phase-shift mask and hyperlens, we present a novel subdiffraction-limited photolithography design. The Alt-PSM is not only acted as a distinct object with phase shifting, but also modulates the transmission by interference of diffracted evanescent waves generated by subwavelength features at the surface. The planar hyperlens, which is alternately filled thin metal and dielectric film, has the ability to convert evanescent waves from the diffraction-limited Alt-PSM immediately into propagating waves. By analyzing the imaging principles and characteristics of this imaging system, and compared it with the traditional model, we find it achieves finer resolution with a well-proportioned reduction. This not only improves the imaging resolution, but also effectively reduces the feature size of chips. This provides an important theoretical basis for the rapid development of microelectronic technology, and will have a wide range of application.Following, with the unique characteristic of metamaterials and coordinate transformation theory, we design a novel trumpet hyperlens. By changing the permittivity of the dielectric in agreement with an effective metamaterial description, this lens is expected to focus light over a broad wavelength range. And by changing the number of layers, we can get a different spot size and focus length. This lens will have a wide range of application for it has a strong ability to focus and higher focusing efficiency.In conclusion, we have proposed the nanolithography design and the novel trumpet hyperlens in this paper. They both can break through diffraction limit, and achieve subwavelength imaging or focusing. This will have important theoretical value and application prospects in nano-optical imaging technology, microfabrication technology, surface-plasmon-polaritons waveguide excitation and so on.