Hi, I have encountered a problem. I tried to reproduce the reflection of all-TiO2 nanopillars on a Si substrate, with a period of 350 nm as mentioned in the literature. Each nanopillar has a width of 200 nm and a thickness of 300 nm. I simulated this using Lumerical FDTD, but I obtained different reflection results in the range of 400 nm to 800 nm. Where could the problem lie? Also, how can I estimate the geometric parameters of a specified reflection peak?
the reference literature is :Yang, B., Liu, W., Li, Z., Cheng, H., Choi, D. Y., Chen, S., & Tian, J. (2019). Ultrahighly saturated structural colors enhanced by multipolar-modulated metasurfaces. Nano letters, 19(7), 4221-4228.
Dear Liu.
The difference between your results and the literature could be mainly due to considerable differences in dispersion relations (refraction index, both real and imaginary part, as a function of the excitation wavelength) considered for any material. These relations can vary considerably depending on the literature source. A good reference point can be found in the following database: RefractiveIndex.INFO - Refractive index database (https://refractiveindex.info/). I do not know what dispersion relations you and the authors of the referenced paper used.
Other issues could be related to the criterion selected for mesh refinement and FDTD simulation. Please, revise the following recommendations for ANSYS Lumerical: https://optics.ansys.com/hc/en-us/articles/360034382614-Selecting-the-best-mesh-refinement-option-in-the-FDTD-simulation-object
I recommend you use the "Conformal variant 2: The Yu-Mittra method 1" for mesh refinement, which is adequate for modeling electrical conductor/dielectric interfaces.
I hope my help has been useful.
Good luck!
Dr. Simón Roa
- Badges
- Science topic
- Similar topics
- Mathematical Sciences
- Graphs