Compact, High‐resolution Inverse‐Designed On‐Chip Spectrometer Based on Tailored Disorder Modes

Abstract

Integrated optical sensors have garnered much interest for lab-on-chip applications such as chemical and biological sensing and detection. Among various ways for detection schemes, spectral analysis performed by a spectrometer has shown great promise. Typically, such spectrometry is carried out in a relatively large device, owing to the fact that spectral resolution is often dictated by large optical path length. Here, a high-resolution compact spectrometer utilizing random scattering events in a disordered medium is demonstrated. The spectrometer is inverse designed by objective-first method and fabricated using two-photon polymerization technique. The compact spectrometer consists of a disordered photonic structure and an inversed-designed mode decomposer. A spectral resolution of 0.25 nm with a bandwidth of 30 nm in the near-infrared regime is realized from a spectrometer occupying a relatively small footprint of 30 × 12.8 µm 2 . The proposed platform has a great potential to be used as a versatile lightweight and compact spectrometer for various applications including on-chip spectrometer and sensing.

Advances in cost-effective integrated spectrometers

“…Based on the laser-induced polymerization effect, current commercial 3D nano printer can implement arbitrary three-dimensional pattern with <200 nm feature size. A variety of demonstrations of 3D-nanoprinted spectrometers have been reported based on different principles ranging from free-space optics to computational reconsctruction 115 , 116 . An additional design dimension could bring unique advantages for 3D nano-printed spectrometers, such as ultra-compact footprint.…”

Broadband and High-Resolution Integrated Spectrometer Based on a Tunable FSR-Free Optical Filter Array

“…However, there are several drawbacks of the FTSs, including high power consumption, large driving voltage, long measurement time, and relatively large footprint. Over the past decade, reconstructive spectrometers, which employ scattering medium to provide a unique fingerprint (speckle) for each probe wavelength, then use computational techniques to reconstruct an incident light spectrum, have emerged. − The physical channel number and device footprint can be reduced dramatically for the sparse spectra. The critical challenges for the reconstructive spectrometer are to develop a series of speckles with an ideally orthogonal spectral response and to reduce the scattering loss within the scattering medium.…”

Metamaterial-enabled arbitrary on-chip spatial mode manipulation

“…1a , through introducing the spatial-mode-parallelism dimension to silicon photonic integrated circuits (PICs), mode-division multiplexing (MDM) can significantly scale the bandwidth density of on-chip interconnects 6 , 7 , and also has great potential in MMF communications where the MMF is excited directly by the multimode waveguide via a multimode grating coupler 8 . Moreover, mode-selective manipulation has greatly promoted the development of diverse information processing fields ranging from performance-enhanced optical sensing 9 , 10 , neuro-inspired photonic computing 11 , to novel nonlinear 12 , and quantum optics devices 13 , 14 . For instance, the coupling of spatial modes with other degrees of freedom (polarization, time, frequency, etc.)…”