Laser‐induced electron coherence is a fascinating topic in manipulating quantum materials. Recently, it has been shown that laser‐induced electron coherence in 2D materials can produce a third‐order nonlinear optical response spatial self‐phase modulation (SSPM), which has been used to develop a novel all‐optical switching scheme. However, such investigations have mainly focused on electron coherence, whereas laser‐induced hole coherence is rarely explored. Here, the observation of the optical Kerr effect in 3D Weyl semimetal TaAs flakes is reported. The nonlinear susceptibility (χ(3)) is obtained, which exhibits a surprisingly high value (with = 9.9 × 10−9 e.s.u. or 1.4 × 10−16 m2 V−2 at 532 nm). This cannot be explained by the conventional electron mobility, but can be well understood by the unique high anisotropic hole mobility of TaAs. The wind‐chime model and χ(3) carrier mobility correlation adequately explain the results, suggesting the crucial role of laser‐induced nonlocal ac hole coherence. These observations extend the understanding of SSPM from 2D to 3D quantum materials with anisotropic carrier mobility and from electron coherence to hole coherence.

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Conductive polymers are promising electrode candidates in the nonenzymatic catalytic detection of small molecule metabolites, due to the tunable electronic conductivity and versatile modifiability. However, the complex catalytic reaction pathway of conductive polymers results in lower detection sensitivity and a narrower linear range compared with clinical metal-based and carbon-based electrodes. Localized surface plasmon resonance (LSPR), characterized by deep strong light-matter coupling, has great potential in driving surface catalytic reactions at an ultrafast rate. Here, we constructed a salix argyracea-like polypyrrole nanowires/silver nanoparticles (PPy/AgNPs) heterojunction electrode using polydopamine as a dopant and chelator. Through cyclic voltammetry, the Mott–Schottky curve, and COMSOL simulation, we demonstrated that the LSPR-excited photocarriers enhanced PPy/AgNPs electrode electrocatalysis. Thus, the detection current response and linear range were significantly improved under the LSPR excitation when taking glucose and hydrogen peroxide as models of small molecule metabolites. Furthermore, we discussed the LSPR-enhanced detection mechanism of PPy/AgNPs electrode from the aspects of the Tafel slope, the apparent electron diffusion coefficient, and the charge transfer resistance. This strategy opens a new avenue toward the design of LSPR-enhanced conductive polymer electrodes.