Abstract
We present a pixel-level angle sensitive detector composed of silicon-on-insulator (SOI) photodiode (PD) stacked with a gold surface plasmon (SP) antenna to affect the direction of the incoming light. The surface plasmons are excited in the grating-type SP antenna and enhance the diffraction efficiency of the grating. The diffracted light is coupled strongly with the propagation light in the SOI waveguide when the phase matching condition is satisfied. The phase matching takes place at a specific angle of light incidence, and the discrimination of the light based on the incident angle is achieved. As spatial patterns in the polar coordinate of the elevation-azimuth angles (θ, ϕ) of the incident light, we present the phase matching condition theoretically, the absorption efficiency in the SOI by simulation, and also the quantum efficiency of the SOI PD experimentally for different SP antennas of one-dimensional (1D) line-and-space (L/S) and two-dimensional (2D) hole array gratings under various polarization angles. 1D grating offers a polarization sensitive angle detection and 2D grating exhibits angle detection in two orthogonal directions, enabling a polarization independent angle sensitivity. A good agreement among the theory, simulation, and experiment are attained. The proposed device features relatively high quantum efficiency as an angle-sensitive pixel (ASP) and gives wider opportunities in applications such as three-dimensional (3D) imaging, depth-of-field extension, and lensless imaging.
Highlights
The current trend in the research field of advanced image sensors is to focus on the development of pixel-level detectors for computational imaging [1,2,3,4]
A novel CMOS image sensor has been developed to detect the angular information as a representative angular sensitive pixel (ASP)
We have investigated the elevation-azimuth angle dependence of the light sensitivity in silicon-on-insulator photodiode (SOI PD) with a surface plasmon (SP) antenna, but the polarization angle directly depends on the azimuth angle because of our previous measurement configuration with one axis goniometer stage [21,22]
Summary
The current trend in the research field of advanced image sensors is to focus on the development of pixel-level detectors for computational imaging [1,2,3,4]. The 5D plenoptic function is the combination of the three spatial coordinates (x, y, z) and the two angle information (θ, φ) which represent elevation and azimuth angles, respectively, of the light ray This function is reduced to 4D data. A novel CMOS (complementary metal-oxide-semiconductor) image sensor has been developed to detect the angular information as a representative angular sensitive pixel (ASP). This sensor utilizes the Talbot effect between two diffraction gratings stacked over a conventional photodiode and it became possible to measure one angular information I(θ) of the incident light [16]. The experimental demonstration of the fabricated devices is done by measuring the directivity of quantum efficiency for different polarizations
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
