title: Guided mode resonance enabled ultra-compact Germanium photodetector for 1.55 μm detection.
abstract: We propose a novel technique of enhancing the photodetection capabilities of ultrathin Ge films for normally incident light at 1.55 μm through the guided mode resonance (GMR) phenomenon. Specifically, by suitably patterning the surface of a Ge thin film, it is possible to excite guided modes which are subsequently coupled to free space radiative modes, resulting in spectral resonances that possess locally enhanced near fields with a large spatial extent. Absorption is found to be enhanced by over an order of magnitude over a pristine Ge film of equal thickness. Furthermore, attenuation of incident light for such a structure occurs over very few grating periods, resulting in significantly enhanced theoretical 3 dB bandwidth-efficiency products of ~58 GHz. The nature of the enhancement mechanism also produces spectrally narrow resonances (FWHM ~30 nm) that are polarization sensitive and exhibit excellent angular tolerance. Finally, the proposed device architecture is fully compatible with existing Si infrastructure and current CMOS fabrication processes.
authors.forename: Alexander Yutong
authors.initials: AY
authors.lastname: Zhu
authors.forename: Shiyang
authors.initials: S
authors.lastname: Zhu
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Lo
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005857:Germanium / Q000528:radiation effects*; D008027:Light; D008904:Miniaturization; D010783:Photometry / Q000295:instrumentation*; D011829:Radiation Dosage; D012031:Refractometry / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014159:Transducers
chemical_list: D005857:Germanium