Combined holographic optical elements for multicolor holographic screens and indicators

Abstract

Abstract. A combination of holographic and diffractive optical elements (HOE-DOEs) for multicolor signs-symbolic information display system, screens and indicators is described. These elements combine the functions of high-efficiency four-level diffractive optical elements with spectral plasmon filters having a variable bandwidth dependent on the angle of incidence. The main parameters of such HOE-DOEs were determined using the Fourier modes method. The theoretical results show that a four-level diffraction grating and a plasmon filter can be combined based on their spectral-angular characteristics, opening up the possibility for their use in display systems. IntroductionCurrently, one of the most promising practical applications of flat optics is the development of holographic and diffractive optical elements (HOE-DOEs) with binary and multi-level surface relief, as well as their integration into optical devices. HOE-DOEs with light guide substrates are used in miniature display systems [1][2][3][4][5][6]. With these combined elements, the weight and size of display and visualization systems can be significantly reduced [3,4], which allows for their use in new applications, especially in automotive and aviation systems [2,4,5], where the display is superimposed on real world imagery.The use of holographic indicators in different climatic conditions requires the selection of special photosensitive materials for HOE-DOEs. These elements may need to be physically protected or recorded directly into the glass [4]. There is a significant problem with the low diffraction efficiency of these devices [1][2][3]. Improved efficiency would allow for the use of less powerful illumination source including the possibility of using OLED-displays. In order to project multi-colored images, HOE-DOEs need to be designed with the specified spectral and angular selectivity. The development of a new type of combined HOE-DOEs with increased diffraction efficiency and spectral-angular selectivity for different photosensitive materials and glass will facilitate the development of a new generation of signs-symbolic information displays, based on holographic optical elements and light guide substrates.

Design and experiments of combined diffractive optical element for virtual displays and indicators

“…A combination of four-level diffraction grating (DG) having high diffraction efficiency with spectral filters that have a bandwidth that varies with the angle of incidence inside a single DOE [8] is shown in Fig. 1.…”