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As a widely used method in the diffractive optics community, the thin-element approximation (TEA) turns out to be very efficient in the calculation of the diffraction efficiencies of thin diffractive elements. On the other hand, it is also known that such an approximation becomes inaccurate when e.g. the period of the diffractive grating becomes small in comparison to the wavelength. We selected two commonly used profiles for transmission gratings (sinusoidal and blazed), and apply TEA and the rigorous FMM/RCWA for their analysis, in order to compare the results from both methods.

VirtualLab Fusion provides various tools to make simulation workflows easier. A very important one among them is the Parameter Run, which sweeps over different value ranges for multiple parameters in an optical setup automatically. You can choose any parameter to vary, either physical values or numerical parameters, and check their influence on the result. Especially for the case of multiple parameters, different configuration modes of the Parameter Run are available: check all possible parameter combinations using the scanning mode; define a specific combination in the programmable/standard mode, or in a random manner, as the need may arise.

Nowadays, many quantum-mechanical effects can be demonstrated with equivalent optical systems. As an example, a passive parity-time (PT) grating with separate modulation of the real and imaginary parts of the refractive index has been used to study the non-Hermitian parity-time symmetry. We construct such a passive PT grating in VirtualLab Fusion and analyze it with the Fourier modal method (FMM, also known as RCWA) to show its asymmetric diffraction property.

Diffraction is a very representative phenomenon that shows the wave nature of light. It explains the behavior of light in the region of a geometric shadow. To take diffraction into consideration is often of concern in modern optics, which is beyond the scope of a pure geometric optics approach. We demonstrate two typical fundamental effects in VirtualLab Fusion: the diffraction caused by aperture truncation and the diffraction due to wavefront aberration.

Diffractive optics has become an indispensable technology in many fields to the point where nowadays it is applied in medical applications as well. One example in this field is the intraocular diffractive lens, which is implanted in the eye for the treatment of cataracts or myopia. The diffractive lens, together with the original human eye structures, makes a hybrid lens system. With VirtualLab Fusion, we show how to model and design such systems, particularly with the workflow that supports the import of Binary 2 surfaces from Zemax OpticStudio®.

A resonant waveguide grating, which is made up of a thin waveguide film in contact with a grating, shows great potential in different applications due to its high optical tunability. With the Fourier modal method (FMM, or RCWA) in VirtualLab Fusion, we analyze the response of such gratings. In the example below, the parameter coupling feature is used to help define the parameters under investigation in a relative manner. Furthermore, the resonant modes within the grating structures are computed as well to study the working principle of such devices.  

Ultrashort pulse lasers, with time duration in femtoseconds, are of great importance and potential for both fundamental research and industrial applications. For example, such lasers enable the extremely precise processing of materials, which is known as “cold” ablation. In VirtualLab Fusion, an ultrashort pulse is modeled as a composition of a broadband spectrum, and the correlation between the different spectral modes is considered. That enables the investigation of ultrashort pulse behavior in both spatial-temporal (or spatial-spectral) domain, as shown in the examples below.

Learn from our optical engineering experts how to use VirtualLab Fusion efficiently. Register for both courses or only one, depending on your previous experience working with VirtualLab Fusion.

Since numerous new features are included in our VirtualLab Fusion Winter Release 2019, these courses would be interesting for current users as well.

USA | 10 – 13 February 2020