Calculation device and calculation method

A calculation device, comprising:

• a calculation portion that divides a sample into a plurality of cells, and calculates an electromagnetic field of the sample by calculating an electromagnetic field of each cell based on a physical property value associated with the cell, wherein the sample includes a numerical solution applying portion, a connecting portion and an analytic solution applying portion that are sequentially arranged in a propagation direction of incident light,
• wherein the calculation portion
• calculates the electromagnetic field of the numerical solution applying portion and the connecting portion by a numerical calculation that uses Maxwell's equations,
• Fourier transforms the calculated electromagnetic field of the connecting portion into a plane wave expressed by a wavenumber vector,
• sets the plane wave of the connecting portion as an initial value, and calculates a wavenumber space electromagnetic field of the analytic solution applying portion by using Helmholtz's equation, when the plane wave propagates the analytic solution applying portion in the propagation direction, and
• calculates the electromagnetic field of the analytic solution applying portion by inverse Fourier-transforming the wavenumber space electromagnetic field of the calculated analytic solution applying portion.