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Nanostructured Surfaces for High Throughput Lensfree Microscopy and Sensing On a Chip

  • Author(s): Khadem Hosseinieh, Bahar
  • Advisor(s): Ozcan, Aydogan
  • et al.
Abstract

Lensfree platforms are becoming valuable alternatives to conventional lens-based imaging and sensing methods because they are compact and cost-effective and provide large field-of-view systems more compatible with microfluidic devices. Due to the lack of lenses in these systems, an additional step of processing is required to obtain the final result; however, digital technology and efficient mathematical algorithms make the task rapid and straightforward. In this dissertation, I introduce a lensfree modality utilizing nanostructured surfaces to provide high throughput and on-chip incoherent imaging and plasmonic sensing. In the imaging implementation of the proposed platform, the emitted incoherent light from an object is modulated by a nanostructured surface on top of which the object is placed. Through a compressive-sensing algorithm, the embedded spatial resolution and intensity information are extracted. In the sensing implementation, the light source illuminates the surface of the microfluidic substrate that is placed on top of an image sensor. The bottom layer of the microfluidic device is a metal-coated glass layer on top of which there are arrays of nano-slits modulating the transmission of light so that the diffraction pattern of those structures on the image sensor alters based on the amount of change in the refractive index. In addition, I explain how the pixel super resolution method can be deployed in lensfree incoherent imaging to provide a high-resolution image out of a series of low-resolution frames that have shifted in relation to each other.

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