Illumination of light on matter normally causes heating and destroys the ordered ground states. Despite this common understanding, recent advances in ultrafast light sources have enabled the non-thermal control of quantum phases. Here, we report the light-induced enhancement of superconductivity in a thin film of an iron chalcogenide FeSe_0.5Te_0.5, which exhibits multiple quantum condensates associated with the multi-orbital character. Upon the photoexcitation, we observed a transient increase of the superfluid density as indicated by the optical conductivity in the frequency range of superconducting gaps. The light-induced enhancement of superconductivity is further corroborated by the photoinduced enhancement of terahertz third harmonic generation, which is accounted for by the Higgs mode response. The ultrafast dynamics of two superfluid components revealed by frequency- and time-resolved terahertz measurements indicate the interplay between the condensates through the interband Cooper pairings while suggesting the potential tunability of the pairing interaction by light in the ultrafast timescale.

光照在物质上通常会导致加热并破坏有序的基态。尽管有这种普遍的理解，但超快光源的最新进展已经实现了对量子相的非热控制。在这里，我们报告了铁硫属化物 FeSe _0.5 Te _0.5薄膜中超导性的光诱导增强，表现出与多轨道特征相关的多个量子凝聚体。在光激发时，我们观察到超流体密度的瞬时增加，如超导间隙频率范围内的光导率所示。太赫兹三次谐波产生的光诱导增强进一步证实了超导性的光诱导增强，这是由希格斯模式响应解释的。频率和时间分辨太赫兹测量揭示的两个超流体组分的超快动力学表明凝聚体之间通过带间库珀配对相互作用，同时表明在超快时间尺度上光对相互作用的潜在可调性。