Ultrafast transient absorption spectroscopy (UFTS) is a widely used technique to determine the change in optical parameters on laser irradiation and can highlight the pathways and the lifetime of decay of the charge carriers. Here, UFTS was used to detect the structural changes occurring in a MoO₃/Ag heterostructure because of dewetting and dealloying. A comparative study of transient absorption behavior of samples exposed to different temperatures indicated a change in phase and crystallinity of the film. Later through GI-XRD, it was concluded that the MoO₃ film has become crystalline at 350 °C along α-(110) plane. A wide plasmonic band in UFTS data of dealloyed sample followed by FESEM showed randomly distributed Ag-Mo nanoporous clusters (315 nm - 6 μm). Tuning of surface plasmon resonance (~19 nm) was seen with etching time. This study proves UFTS's suitability for correlating the structural change in a film or heterostructure of films with spectroscopic results.

超快速瞬态吸收光谱法（UFTS）是一种广泛使用的技术，可以确定激光辐照时光学参数的变化，并且可以突显电荷载流子的衰变路径和寿命。此处，UFTS用于检测由于去湿和脱合金而在MoO ₃ / Ag异质结构中发生的结构变化。对暴露于不同温度的样品的瞬态吸收行为的比较研究表明，薄膜的相和结晶度发生了变化。后来通过GI-XRD，得出MoO ₃膜在350°C时沿α-（110）平面结晶。脱合金样品的UFTS数据中的宽等离子带，然后进行FESEM，显示出随机分布的Ag-Mo纳米多孔簇（315 nm-6μm）。随蚀刻时间观察到表面等离激元共振的调谐（〜19 nm）。这项研究证明了UFTS适合将膜的结构变化或膜的异质结构与光谱结果相关联。