VirtualLab Fusion includes several technologies for modeling complete optical systems from nano-structure to macro-structure feature sizes.

Four types of free-space propagation methods for accurately modeling paraxial to high NA regions in optical systems

Multiple Maxwell solvers for fast and accurate modeling of many types of optical components, such as: diffractive optical elements, gratings, nanostructured components, scatterers, etc.

Three types of Fourier Transforms to efficiently analyze regions in optical systems with little diffraction to significant diffraction

The free space propagation methods in VirtualLab Fusion are:

• Spectrum of Plane Waves
• Fresnel operator
• Far field operator
• Geometrical optics operator

VirtualLab includes an automatic propagation selection algorithm for calculating the most efficient propagation method in each region of the light path that optimizes error vs calculation effort.

The recommended propagation method in each region can either be used or it can be manually overridden.

For rigorous analysis of optical components, VirtualLab Fusion includes multiple Maxwell solvers.

To achieve Fast Physical Optics, Maxwell solvers are selectively applied in each region of the light path to optimize accuracy vs numerical effort.
The solutions in each region are connected through non-sequential field tracing to solve Maxwell's equations in the entire optical system.

Below are three examples of Maxwell solvers in VirtualLab. As a beam propagates through different regions, in the light path, calculations are done in the spatial domain (x-domain) or the spatial frequency domain (k-domain) as shown.

See below (Fourier Transforms) for more discussion of changing between these domains.

Example 1: Including free space, SLM and grating

Example 2: Including free space and grating

Example 3: Including free space and beam splitter

In order to efficiently model electromagnetic fields throughout optical systems that include diffractive optical elements, nanostructured components, scatterers, etc., VirtualLab Fusion includes three types of Fourier Transforms.

This speeds up Maxwell solver calculation time by changing from the spatial domain

(x-domain) to the more efficient spatial frequency domain (k-domain) in regions where rigorous physical optics analysis is required.

VirtualLab includes three types of Fourier Transforms.

• Fast Fourier Transform
• Semi-Analytical Fourier Transform
• Pointwise Fourier Transform

The Fast Fourier Transform is a rigorous method for paraxial regions with significant, slow diffraction

The Semi-Analytical Fourier Transform (SAFT) is a rigorous hybrid analysis for fields having high quadratic phases.

The quadratic phase from the input field/spectrum is separated from the residual phase. The second order polynomial phase terms are handled analytically. Since the sampling required for the residual field is relatively small, the computational effort is reduced in these regions, while still providing rigorous analysis.

The Pointwise Fourier Transform (also called homeomorphic Fourier Transform) is approximate for regions with strong, smooth wavefront phase and high NA.

The Fourier Transform used in each region can be selected manually or automatically within VirtualLab. The automatic selection algorithm is based on the ratio of geometric to diffractive power in each region.

Fourier Transforms can be applied to sources, optical components and detectors.