Mateusz Surma
supervisor: Maciej Sypek
Diffractive optical elements (DOEs) can be part of any optical setup designed for narrowband system. DOE’s reduced volume leads to the reduction of the total weight of the setup. Although, in on-axis regime parameters of DOEs may be similar to refractive optics, the design procedure is entirely different. In off-axis case refractive elements becomes very bulky and some configurations are even not possible to be realized.
DOE design methods are independent of selected wavelength, which opens the use of terahertz (THz) radiation as a potential choice for testing of designing procedures. Additionally, THz radiation is attractive due to the availability of relatively easy and cost-effective production methods such as 3D printing.
The issue related to finding DOE’s shape can be interpreted as optimization problem, especially in off-axis case. In this way the optimization methods search for solution (DOE’s phase distribution - single- or multi-plane structures) that binds known input and output intensity distributions. However, one of potential improvements is to optimize DOE phase distribution to assure forming complex output intensity pattern working in broader spectral range.
This presentation introduces basic concepts connected with design and production of DOEs with special focus on THz radiation band and off-axis focusing. Then, the overview of optimization methods is provided with perspective of use in the design of broadband and focusing off-axis DOEs.