Scalable On-Chip Microdisk Resonator Spectrometer

On-chip micro-spectrometers are sought after with great effort owing to extensive potential applications in mobile optical sensing and imaging. By multiplexing more physical channels, the reconstructive spectrometers based on the spectral-to-spatial mapping technique can improve the spectral range. However, this method is challenging to implement and sustain due to the increase in system complexity and the decrease of dynamic range or spectral resolution. Here, a micro-spectrometer utilizing a single tunable microdisk resonator (MDR) is demonstrated. Such a single MDR spectrometer has only one physical channel to receive all spectral components with a compact size, overcoming the trade-off among spectral resolution, spectral range, and dynamic range. Leveraging the wavelength and temperature-dependent response matrix, unknown spectra are reconstructed from their corresponding output light intensity vector. The fabricated device illustrates a high resolution of 0.01 nm for a dual peak and a medium resolution of 0.2 nm in the 20 nm spectral range. A wide variety of complex input spectra, including narrowband and broadband spectral signals, can be well recovered, exhibiting the robustness of the spectral reconstruction approach. Moreover, this proposed spectrometer exhibits ease of scalability and flexible configuration to a spectrometer array covering a set of desired and even discrete spectral ranges.

Automated summary

This article introduces a micro-spectrometer that utilizes a single tunable microdisk resonator (MDR). By leveraging the wavelength and temperature-dependent response matrix, unknown spectra can be reconstructed from their corresponding output light intensity vector. The fabricated device demonstrates high and medium resolution capabilities and can recover a wide variety of complex input spectra, showing the robustness of the spectral reconstruction approach. Moreover, this spectrometer can be easily scaled and configured to cover desired spectral ranges.