By virtue of its narrow pulse width and high peak power, the femtosecond pulsed laser can achieve high-precision material modification, material additive or subtractive, and other forms of processing. With additional good material adaptability and process compatibility, femtosecond laser-induced application has achieved significant progress in flexible electronics in recent years. These advancements in the femtosecond laser fabrication of flexible electronic devices are comprehensively summarized here. This review first briefly introduces the physical mechanism and characteristics of the femtosecond laser fabrication of various electronic microdevices. It then focuses on effective methods of improving processing efficiency, resolution, and size. It further highlights the typical progress of applications, including flexible energy storage devices, nanogenerators, flexible sensors, and detectors, etc. Finally, it discusses the development tendency of ultrashort pulse laser processing. This review should facilitate the precision manufacturing of flexible electronics using a femtosecond laser.

Electrically tunable metasurfaces can realize two-dimensional pixelated spatial light modulation and have a wide range of applications in optical switching, free-space communication, high-speed imaging, and so on, arousing the interest of researchers. Here, a gold nanodisk metasurface on a lithium-niobate-on-insulator (LNOI) substrate is fabricated and experimentally demonstrated as an electrically tunable optical metasurface for transmissive free-space light modulation. Using the hybrid resonance formed by the localized surface plasmon resonance (LSPR) of gold nanodisks and the Fabry–Perot (FP) resonance, the incident light is trapped in the gold nanodisk edges and a thin lithium niobate layer to realize field enhancement. In this way, an extinction ratio of 40% is achieved at the resonance wavelength. In addition, the proportion of hybrid resonance components can be adjusted by the size of the gold nanodisks. By applying a driving voltage of ± 2.8 V, a dynamic modulation of 135 MHz is achieved at resonant wavelength. The highest signal-to-noise ratio (SNR) is up to 48 dB at 75 MHz. This work paves the way for the realization of spatial light modulators based on CMOS-compatible LiNbO₃ planar optics, which can be used in lidar, tunable displays, and so on.

Six-junction GaAs laser power converts (LPCs) were designed and fabricated. Each subcell is vertically connected by p++-AlGaAs: C/n++-AlGaAs: Si: Te (1:2) tunnel junction with good thermal stability and a record peak tunneling current density of 1867 A/cm². The I-V characteristics of LPCs with an aperture of 10×10 mm² were investigated as a function of laser power and temperature. Maximum conversion efficiency and output power of 57.7% and 15.4 W, respectively, and a continuous stable operation at 22.9 W for over 550 hours were demonstrated. The temperature coefficient of conversion efficiency and open-circuit voltage were -0.197%abs/°C and -8.15 mV/°C, respectively, under 808 nm laser illumination of 21.0 W. Furthermore, an array of 100 large-scale (41×46 mm²) LPCs with an output power of 179 W under 1 kW laser irradiation at 20 m wireless transmission was developed.

InGaAs metamorphic laser power converters (LPCs) have the potential to deliver electrical energy over distances of several kilometers. In this study, metalorganic chemical vapor deposition (MOCVD) was used to grow InGaAs-based LPCs with an absorption wavelength of 1064 nm. At step thicknesses of 2800 nm, overshoot thicknesses of 6000 nm, reverse component and thicknesses of 2.4% and 700 nm, respectively, a surface roughness of 6.0 nm and InGaAs (24%) lattice relaxation of 93.7% of the InGaAs metamorphic buffer were obtained. The I-V characteristics of LPCs with 10 × 10 mm² apertures were investigated as a function of laser power and temperature. The maximum conversion efficiency of 44.1% and 550 hours of continuous stable operation at 4 W were demonstrated. Under 1064 nm laser illumination of 4 W, the temperature coefficients for the conversion efficiency and open-circuit voltage were -0.1%abs/°C and -1.6 mV/°C, respectively, and the LPC output power fluctuation was less than 0.5% during 216 hours of continuous temperature change from 20 to 100°C.

One hotspot of integrated optics is how to realize a highly integrated and high-gain on-chip amplification system in a thin film of lithium niobate on insulator (TFLNOI). Here, a low erbium-doped TFLNOI waveguide amplifier with shorter length is demonstrated using the photolithography-assisted oblique-reactive ion etching technique. A maximum net internal gain of 5.4 dB in the small-signal-gain regime is measured at the peak emission wavelength of 1531.35 nm for a waveguide length of 1.5 mm and an erbium-doped concentration of 0.1 mol. %, indicating a gain per unit length of 36 dB cm⁻¹. This work paves the way for the monolithic integration of diverse active and passive photonic components on the TFLNOI platform.

During the implementation of laser wireless power transmission (LWPT), various factors, such as clouds and atmospheric turbulence, can potentially result in nonuniform irradiation, leading to a power mismatch of the photovoltaic (PV) array. Dynamic reconfiguration technology which adopted in solar energy system is an effective method to improve the power output of PV arrays, but the current execution speed and accuracy cannot meet the fast response requirements of LWPT. In this article, a novel adaptive threshold iteration algorithm for irradiance equalization based on total-cross-tied (TCT) configuration is proposed. Based on this algorithm, a large number of data samples characterized and labeled by irradiance and optimal layout are obtained in the simulation platform. The irradiance values are then converted into current values of special nodes for the training of deep neural networks, which simplifies both model complexity and hardware complexity. A theoretical analysis of the simulation was performed on a 3×4 scale PV array, followed by the design of the hardware circuit and evaluation of the experimental results with metrics. The results show that the output power enhancement of the array can reach up to 63.29% compared to TCT-type configuration. The conversion efficiency is improved by 17.21%, and the reconfiguration execution time is about 61 ms.