Simulation of photodetection using finite-difference time-domain method with application to near-field subwavelength imaging based on nanoscale semiconductor photodetector array

Abstract

Simulation of detecting photoelectrons using multi-level multi-electron (MLME) finite-difference time-domain (FDTD) method with an application to near-field subwavelength imaging based on semiconductor nanophotodetector (NPD) array is reported. The photocurrents from the photodiode pixels are obtained to explore the resolution of this novel NPD device for subwavelength imaging. One limiting factor of the NPD device is the optical power coupling between adjacent detector pixels. We investigate such power coupling in the presence of absorbing media as well as the spatial distributions of the electric field and photoelectron density using the MLME FDTD simulation. Our results show that the detection resolution is about one tenth of the operating wavelength, which is comparable to that of a near-field scanning optical microscope based on metal clad tapered fiber.

Plasmonic Superlens Imaging Enhanced by Incoherent Active Convolved Illumination

“…The images could then be directly read out with a subwavelength near-field probe 2,6,66-74 or detector [75][76][77][78][79][80][81][82][83][84] small enough to resolve the important features.…”

Nanoscale Photodetector Array and Its Application to Near-Field Nano-Imaging

“…A new idea using multi-level multi-electron (MLME) semiconductor FDTD model has been developed by Huang and Ho (Huang 2002;Huang & Ho 2006), in which multiple energy band levels to describe the essential characteristics of the semiconductor energy band structures have been incorporated. This simulation scheme has also been successfully utilized in various photonic device applications with active semiconductors including photodetector, photonic crystal fiber, photonic transistor, whispering gallery resonator, and so on (Kim et al 2008;Khoo et al 2008). In order to understand the working mechanism of NPD array as a nanoscale imaging device, a MLME FDTD method has been adopted in this Chapter.…”

Near-field nano-imaging by nanophotodetector array

“…Conceptually, a photodetector can be simplified as a medium with two energy levels and the photocurrent can be derived from emptying the excited states through an external electric circuit as shown in Fig. 5 [6] . The photocurrent generated is dependent on the incident (excitation) wavelength, and the energy band gap structure of the semiconductor material.…”