Dynamic infrared thermal camouflage technology has attracted extensive attention due to its ability to thermally conceal targets in various environmental backgrounds by tuning thermal emission. The use of phase change materials (PCMs) offers numerous advantages, including zero static power, rapid modulation rate, and large emissivity tuning range. However, existing PCM solutions still encounter several practical application challenges, such as temperature uniformity, amorphization achievement, and adaptability to different environments. In this paper, we present the design of an electrically controlled metal-insulator-metal thermal emitter based on a PCM metasurface, and numerically investigate its emissivity tunability, physical mechanisms, heat conduction, and thermal camouflage performance across different backgrounds. Furthermore, the influence of the quench rate on amorphization was studied to provide a guidance for evaluating and optimizing device structures. Simulation results reveal that the thermal emitter exhibits a wide spectral emissivity tuning range between 8 and 14 μm, considerable quench rates for achieving amorphization, and the ability to provide thermal camouflage across a wide background temperature range. Therefore, it is anticipated that this contribution will promote the development of PCM-based thermal emitters for practical dynamic infrared thermal camouflage technology with broad applications in both civilian and military domains.

Efficiently tuning the output intensity of an optical device is of vital importance for the establishment of optical interconnects and networks. Thermo-optical modulation is an easily implemented and convenient approach and has been widely employed in photonic devices. In this paper, we proposed a novel thermo-optical modulator based on a microfiber knot resonator (MKR) and graphene heater. Upon applying voltage to graphene, the resonant property of the MKR could be thermally tuned with a maximum phase shift of 2.1π. Intensity modulation shows a fast optical response time thanks to the high thermal conductivity of graphene and the thin microfiber diameter of the MKR.

All-optical modulation based on the photothermal effect of two-dimensional (2D) materials shows great promise for all-optical signal processing and communication. In this work, an all-optical modulator with a 2D PtSe2-on-silicon structure based on a microring resonator is proposed and demonstrated utilizing the photothermal effect of PtSe2. A tuning efficiency of 0.0040nm·mW?1 is achieved, and the 10%–90% rise and decay times are 304 μs and 284 μs, respectively. The fabricated device exhibits a long-term air stability of more than 3 months. The experimental results prove that 2D PtSe2 has great potential for optical modulation on a silicon photonic platform.

Q-switched fiber lasers are integral tools in science, industry, and medicine due to their advantages of flexibility, compactness, and reliability. All-optical strategies to generate ultrashort pulses have obtained considerable attention as they can modulate the intracavity Q factors without employing costly and complex electrically driven devices. Here, we propose a high-performance all-optical modulator for actively Q-switched pulse generation based on a microfiber knot resonator deposited with V2CTx MXene. Experimental results show that the obtained Q-switching pulses exhibit a wide adjustment range of repetition rate from 1 kHz to 20 kHz, a high signal-to-background contrast ratio of ～55dB, and a narrow pulse width of 8.82 μs, indicating great potentials of providing a simple and viable solution in photonic applications.