image: Figure | Chaotic cavity and circular microdisk cavity. a, schematic of circular microdisk and its strong periodicity visualized by correlation function, b, schematic of chaotic cavity and its weak periodicity visualized by correlation function. The calculated PSOS, the corresponding ray trajectory in real space marked with different colors in PSOS, and supporting resonant modes of c, the circular microdisk cavity and d, chaotic cavity, respectively.
Credit: Yikai Su et al.
In a new paper published in Light: Science & Applications, a team of scientists, led by Professor Xuhan Guo and Yikai Su from State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, China, has reported an ultra-compact chaos-assisted computational spectrometer, thoroughly overcoming the three-way trade-off among physical size, resolution, and operational bandwidth. A broad operational bandwidth of 100 nm can be attained with a high spectral resolution of 10 pm, encapsulated within an ultra-compact footprint measuring 20×22 μm², which is compatible with other nano-materials-based computational spectrometers. These scientists summarized the principle of their chaos-assisted spectrometers:
“Chaotic system, whose eventual behavior is exponentially sensitive to the small deviation of initial condition, is usually avoided in most cases. However, for some specific scenarios, the chaotic behavior can be transformed into a dominant resource to efficiently achieve requirements, such as the application in computational spectrometer. The computational spectrometer can effectually identify the input spectral signal by means of the high-random response matrix, yet requiring complex cascading configurations and up to millimeter-scale footprints for high-random sampling. While the idea of employing chaotic spectra in spectrometry offers a brand-new paradigm for the miniaturization of high-performance optical spectrometer.”
“Therefore, we utilize a single chaotic cavity whose boundary is smoothly deformed into a Limaçon of Pascal shape to leverage the chaotic spectral information. We successfully utilize the chaotic behavior to effectively eliminate periodicity in resonant cavities, facilitating a decorrelated response matrix with a high degree of diversity. Employing this high-quality response matrix, we experimentally achieve ultra-high spectral resolution in a broadband operational bandwidth, attaining a record high of bandwidth-to-resolution ratio per footprint.” These scientists expressed their experiments.
“Moreover, current on-chip computational spectrometers generally consume high power consumption of over 30 mW, whereas our chaos-assisted spectrometer only requires a low power consumption of 16.5 mW. The substitution of grating couplers (GCs) with edge couplers permits a substantial expansion of the operational bandwidth to over 300 nm. This proposal can be transplanted into other wavelength bands via simply adjusting the dimension of the chaotic cavity in accordance with wavelength among silicon transparent window, or transplanted into other material systems. Furthermore, the resources required by our chaos-assisted spectrometer can be borne by existing consumer mobile devices, providing a new technical path for the development of low-power, low-cost portable spectral sensing.” These scientists added.
Journal
Light Science & Applications
Article Title
Miniaturized chaos-assisted Spectrometer