We report on a study and test of two 6000-groove/mm prototype holographic gratings for NASA's FarUltraviolet Spectroscopic Explorer (FUSE) mission. The first grating was designed and developed onthe basis of the FUSE requirements as specified at the end of the first study in 1992. This design relieson an ellipsoidal grating, recorded with aberrated wave fronts to correct sagittal coma. The secondgrating corresponds to the new design adopted after the complete mission was restructured in1993. With this solution a new family of spherical holographic gratings recorded with stigmaticsources was permitted to increase the aperture size while simplifying the figuring and recording of theblank. The design, fabrication, and testing of each prototype are described, and we show that thechallenging requirement of a 30,000 resolving power at 1000 Å, with a 25% groove efficiency, is reached.
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http://dx.doi.org/10.1364/AO.35.003653 | DOI Listing |
Holographic displays have the potential to reconstruct natural light field information, making them highly promising for applications in augmented reality (AR), head-up displays (HUD), and new types of transparent three-dimensional (3D) displays. However, current spatial light modulators (SLMs) are constrained by pixel size and resolution, limiting display size. Additionally, existing holographic displays have narrow viewing angles due to device diffraction limits, algorithms, and optical configurations.
View Article and Find Full Text PDFField-of-view (FOV) and resolution are two critical performance metrics of a near-to-eye display (NED) and are primarily limited by the refractive index (RI) of the waveguide combiner and the number of available pixel counts of the micro display. A high RI material (n = 2.0) is required to transfer an image exceeding a 60 degree full FOV using traditional techniques.
View Article and Find Full Text PDFThis Letter discusses the limitations of immersion-free recording schemes for holographic waveguide displays. Traditional holographic recording of waveguides requires recording angles exceeding the critical angle of the hologram-cladding interface. Achieving these angles necessitates edge-lit exposure using prisms and immersion liquids, which are challenging for roll-to-roll mass production and hinder widespread adoption.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Institute of Communications Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
A core dielectric cylindrical rod wrapped in a dielectric circular pipe whose outer surface is enclosed by a helical conducting strip grating that is skewed along the axial direction is herein analyzed using the asymptotic strip boundary conditions along with classical vector potential analysis. Targeted for use as a cylindrical holographic antenna, the resultant field solutions facilitate the aperture integration of the equivalent cylindrical surface currents to obtain the radiated far fields. As each rod section of a certain skew angle exhibits a distinct modal attribute; this topology allows for the distribution of the cylindrical surface impedance via the effective refractive index to be modulated, as in gradient-index (GRIN) materials.
View Article and Find Full Text PDFSci Rep
January 2025
Faculty of Physics, Warsaw University of Technology, 75 Koszykowa Str., 00-662, Warszawa, Poland.
Surface relief grating formation in photo-responsive azo polymers under irradiation is a long-ago-found phenomenon, but all the factors governing its efficiency are still not fully recognized. Here, we report on the enormous impact of the polymer thickness on the possibility of fabrication of extremely high-amplitude surface deformations. We performed prolonged holographic recordings on the layers of the same azobenzene poly(ether imide), which had substantially different optical transmittances at the recording wavelength and revealed that the depths of the inscribed relief structures increased with the polymer thickness from a nondetectable value up to almost 2 µm, unaffected by the presence of a polymer-glass substrate interface in either sample.
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