RCWA is a rigorous method and is able to provide any information you want, such as transmission, reflection, diffraction, field profiles, etc.  Since it decomposes fields into set of plane waves, it is most efficient when the field profile approaches that of plane waves.  This happens in structures with low to moderate index contrast, but the method can also be applied to metal structures albeit less efficiently.  This means you can get very accurate results with very few terms to be solved so the simulations are fast.  It is also very good for layered media.  You will see it applied to diffraction gratings, resonant gratings, and sometimes to photonic crystals.

To get a deeper understanding, it is necessary to know a little more about the method.  It is a semi-analytical technique, meaning it picks one direction (longitudinal) to solve analytically and the other two (transverse) to be solved numerically.  RCWA uses a discrete Fourier transform to discretize the fields in the transverse direction.  This means it represents the fields and materials as a set of plane waves (or planar gratings), so RCWA is extremely fast and efficient for devices with low to moderate index contrast where the waves are more like pure plane waves.  The longitudinal direction is solved analytically so the layers can be any thickness without affecting the computational burden.  A layer can be picometers to megameters without affecting speed for efficiency at all.  It can also very efficiently handle multilayer devices and devices with thousands or even millions of layers.

If you want some high level discussion of RCWA, check out Lecture 1 at the following link.  If you want to see the details of RCWA, check out Lectures 18, 19, and 21-23.  There are also a lot of resources on this website if you want to write your own RCWA code.

http://emlab.utep.edu/ee5390cem.htm

Hope this helps!

RCWA is a rigorous method and is able to provide any information you want, such as transmission, reflection, diffraction, field profiles, etc.  Since it decomposes fields into set of plane waves, it is most efficient when the field profile approaches that of plane waves.  This happens in structures with low to moderate index contrast, but the method can also be applied to metal structures albeit less efficiently.  This means you can get very accurate results with very few terms to be solved so the simulations are fast.  It is also very good for layered media.  You will see it applied to diffraction gratings, resonant gratings, and sometimes to photonic crystals.

To get a deeper understanding, it is necessary to know a little more about the method.  It is a semi-analytical technique, meaning it picks one direction (longitudinal) to solve analytically and the other two (transverse) to be solved numerically.  RCWA uses a discrete Fourier transform to discretize the fields in the transverse direction.  This means it represents the fields and materials as a set of plane waves (or planar gratings), so RCWA is extremely fast and efficient for devices with low to moderate index contrast where the waves are more like pure plane waves.  The longitudinal direction is solved analytically so the layers can be any thickness without affecting the computational burden.  A layer can be picometers to megameters without affecting speed for efficiency at all.  It can also very efficiently handle multilayer devices and devices with thousands or even millions of layers.

If you want some high level discussion of RCWA, check out Lecture 1 at the following link.  If you want to see the details of RCWA, check out Lectures 18, 19, and 21-23.  There are also a lot of resources on this website if you want to write your own RCWA code.

http://emlab.utep.edu/ee5390cem.htm

Hope this helps!

Thanks a lot! It really helps!