Designing open channels in random scattering media for on-chip spectrometers
- 5 August 2020
- journal article
- research article
- Published by Optica Publishing Group in Optica
- Vol. 7 (8), 934-939
- https://doi.org/10.1364/optica.391612
Abstract
On-chip spectrometers with tailored spectral range and compact footprint have been pursued widely in the last decade. Splitting different frequencies typically requires a propagation length that scales inversely with the frequency resolution, which leads to a trade-off between resolution and size. Scattering media in the diffusive regime provide a long light path and multipath interference in a compact area, resulting in strong dispersive properties that can be used for on-chip com-pressive spectrometry. However, the performance suffers from the low light transmission through the diffusive medium. It has been found that there exist "open channels" such that light with certain wavefronts can pass through the medium with high transmission. Here we show that a scattering structure can be designed so that open channels match target input/output channels in order to maximize transmission while keeping the dispersive properties typical of diffusive media. Specifically, we use inverse design to generate a scattering structure where the open channels match the output waveguides at desired wavelengths. For a proof of concept, we propose a 1 x 10 multiplexer covering a band of 500 nm in the mid-infrared spectrum, with a footprint of only 9.4 mu m x 14.4 mu m. We also show that filters with nearly arbitrary spectral response can be designed, enabling a new degree of freedom in on-chip spectrometer design, and we investi-gate the ultimate resolution limits of these structures. The structures can also be designed based on a simple geometry consisting of circular holes with diameters from 200 to 700 nm etched in a dielectric slab, making them highly suited for fabrication. With the help of compressive sensing, the proposed method represents an important tool in the quest towards integrated lab-on-a-chip spectroscopy. (c) 2020 Optical Society of America under the terms of the OSA Open Access Publishing AgreementKeywords
Funding Information
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (022.005.001)
This publication has 41 references indexed in Scilit:
- On-Chip Compressed Sensing Fourier-Transform Visible SpectrometerIEEE Photonics Journal, 2018
- Integrated nano-opto-electro-mechanical sensor for spectrometry and nanometrologyNature Communications, 2017
- Mid-Infrared Silicon-on-Insulator Fourier-Transform Spectrometer ChipIEEE Photonics Technology Letters, 2015
- Waveguide-integrated photonic crystal spectrometer with camera readoutApplied Physics Letters, 2014
- A high-resolution spectrometer based on a compact planar two dimensional photonic crystal cavity arrayApplied Physics Letters, 2012
- A high-resolution silicon-on-insulator arrayed waveguide grating microspectrometer with sub-micrometer aperture waveguidesOptics Express, 2007
- Very Compact Arrayed-Waveguide-Grating Demultiplexer Using Si Photonic Wire WaveguidesJapanese Journal of Applied Physics, 2004
- Planar waveguide echelle gratings in silica-on-siliconIEEE Photonics Technology Letters, 2004
- Monolithic integrated wavelength demultiplexer based on a waveguide Rowland circle grating in InGaAsP/lnPJournal of Lightwave Technology, 1998
- Demonstration of a 15*15 arrayed waveguide multiplexer on InPIEEE Photonics Technology Letters, 1992