Non‐Destructive Thermal Evaluation on Laser‐Stimulated 3D Functional Nanomembranes via Stokes and Anti‐Stokes Raman Scattering

Abstract 3D nanomembranes, defined as freestanding thin films, exhibit unique optical and optoelectronic properties under light or laser illumination due to enhanced light absorption and broad‐angle detection. These features enable widespread applications, including passive (e.g., optical microcavities, sensors, metamaterial fibers) and active devices (e.g., phototransistors, bolometers, photodetectors). However, due to low heat capacity and limited thermal dissipation in 3D nanomembranes with tens‐of‐nanometer thickness, thermal accumulation occurs under laser illumination and often compromises device performance. Here, a systematic, non‐destructive thermal evaluation of 3D functional nanomembranes using Stokes and anti‐Stokes Raman scattering is presented. Laser‐stimulated local temperature is experimentally determined from the Stokes‐to‐anti‐Stokes intensity ratio and validated by finite element simulations. Both experimental and simulation results reveal significant thermal accumulation, with local temperature reaching ≈1300 K under laser irradiation. To manage this thermal effect, laser parameters and ambient conditions are optimized for precise thermal control. By integrating Raman‐based measurements with simulations, thermal evaluation and management of 3D nanomembranes, enabling rational design of passive and active devices—such as preventing thermal damage in 3D Si microtube resonators and enhancing response in VO 2 ‐based bolometers, are achieved. This work provides a promising strategy for the thermal design of 3D microdevices in photonics and optoelectronics.