Shouhuan Zhou

This study presents a miniaturized mid- to long-wave infrared computational spectrometer based on metasurface filter arrays fabricated on silicon and germanium substrates. Using electron-beam lithography, we created multi-channel filters that leverage subwavelength amplitude control targeting the 2.5–6.5 μ m and 8–14 μ m bands. Two computational spectral reconstruction methods were demonstrated based on a deep neural network algorithm: a portable approach using a thermal camera for the 8–14 μ m band, and Fourier-transform infrared-based method simulating single-pixel detection. Experimental results on materials such as cellophane and glass confirmed effective recovery of spectral features, demonstrating that the proposed metasurface filters combined with computational reconstruction can enable cost-effective, integrated computational reconstruction spectrometers.

We propose a heat-reconfigurable metasurface composed of the silicon-based gold grating. The asymmetric Fano-like line shape is formed due to the mutual coupling of the local surface plasmon (LSP) in the gap between the two layers of Au gratings and the surface propagating plasmon (SPP) on the surface of the Au gratings. Then, we effectively regulate the Fano resonance by applying a bias voltage to laser-induced graphene (LIG), to generate Joule heat, so that the resonant dip of one mode of the Fano resonance can shift up to 28.5 nm. In contrast, the resonant dip of the other mode barely changes. This effectively regulates the coupling between two resonant modes in Fano resonance. Our study presents a simple and efficient method for regulating Fano-like interference in the near-infrared band.

We present a hybrid device based on graphene-coupled silicon (Si) photonic crystal (PhC) cavities, featuring triple light detection, modulation, and switching. Through depositing single-layer graphene onto the PhC cavity, the light-graphene interaction can be enhanced greatly, which enables significant detection and modulation of the resonant wavelength. The device is designed to generate a photocurrent directly by the photovoltaic effect and has an external responsivity of ∼14 mA/W at 1530.8 nm (on resonance), which is about 10 times higher than that off-resonance. Based on the thermo-optical effect of silicon and graphene, the device is also demonstrated in electro-optical and all-optical modulation. Also, due to the high-quality (Q) factor of the resonate cavity, the device can implement low threshold optical bistable switching, and it promises a fast response speed, with a rise (fall) time of ∼0.4 μs (∼0.5 μs) in the all-optical switch and a rise (fall) time of ∼0.5 μs (∼0.5 μs) in the electro-optical hybrid switch. The multifunctional photodetector, modulator, and optical bistable switch are achieved in a single device, which greatly reduces the photonic overhead and provides potential applications for future integrated optoelectronics.

We propose and demonstrate a novel flexible and elastic vibration-displacement fiber sensor with a doped polydimethylsiloxane (PDMS) micro-fiber based on model interference. High resolution three-dimensional displacement measurement is achieved through monitoring the output pattern and variation of power. The sensor with a length of about 200 μm reveals frequency range from 50 Hz to 14 kHz, covering all the human voice frequency, with greatly enhanced high signal to noise ratio (SNR) reaching up to 66 dB. This work suggests a simple structure, small size and low cost fiber-based convenient way to achieve a multifunctional sensing applications including human motion detection.

We experimentally investigate a stable freestanding whispering gallery mode (WGM) microlaser based on polymer microdisk formed by a ~500 µm diameter microfiber knot. A quality factor of about 14 700 and a relatively low lasing threshold with about 38.0 µJ/pulse are demonstrated in this structure. When a polymer microdisk is pumped by a 532 nm wavelength pulse laser, WGM lasing with a free spectral range (FSR) of 0.15 nm is observed from the polymer microdisk laser. This work provides a convenient and efficient approach to achieving a WGM microlaser based on a polymer microdisk and collecting the output light.