capability is critical for holographic near-eye displays. Since most systems employ phase-only spatial light modulators (SLMs), computer-generated holograms (CGHs) must be encoded as phase-only holograms (PoHs). This work presents two approaches for PoH-based CGH generation from plane images: a direct single-step method (D-PoH) and an iterative method (I-PoH). Both utilize the Compact Space-Bandwidth Angular Spectrum (CSW-AS) technique for propagation, which is optimal for wide-angle scenarios. We evaluate their accuracy and zero-padding requirements. Results show that I-PoH provides ahigher quality image, but at the cost of cyclic computations and the requirement of substantially larger zero-padding compared to D-PoH, limiting its efficiency for wide-angle applications. Incontrast, I-PoH achieves a maximum field of view (FoV) of 39 degrees, while D-PoH enables a significantly larger FoV of 54 degrees, for a PC with 64GB RAM. These findings demonstrate the advantage of direct single-step encoding for achieving wide-angle holographic displays.
study presents a Free Space Optical Communication system using InP-based integrated transceivers, demonstrating multichannel transmission capabilities. The system utilizes photonic integrated circuits (PICs) to achieve compact, energy-efficient transceivers suitable for scalable optical communication applications. Successful multi-channel data transmission at rates of up to 10 Gb/s was achieved in both indoor (2 m) and outdoor (up to 10 m) environments. The design incorporates distributed Bragg reflector (DBR) lasers, electroabsorption modulators, and arrayed waveguide grating (AWG) multiplexers. The system showcases high-quality transmission with low bit-error rates (BER <= 10-11) and minimal power penalties.
this work, two series of glasses of the NaF-Al2O3-P2O5 ternary system with the Na3Al2(PO4)2F3 nominal composition, doped with Er3+(1% and 0.5%) and Yb3+ ions, were synthesized by a standard melt-quenching method, and their up-conversion photoluminescence properties were studied. The as-received amorphous materials were excited by the IR laser radiation with a wavelength of 976 nm, and their emission spectra in the visible range were measured. The optical measurements were focused on the up-conversion photoluminescence spectra in the visible range. It was found that stronger up-conversion effects were observed for the series containing 1 wt% Er2O3. In the case of 0.5 wt% Er2O3, the emission response was weaker, comparable with the background noise.
This study presents a fan-in coupler architecture for a four-core fiber, implemented using a single diffractive optical element (DOE). The DOE selectively excites two opposite cores while the remaining ones serve as receiving channels. The DOE was designed using an iterative algorithm, resulting in a computer-generated hologram and fabricated using two-photon polymerization (TPP). Numerical simulations and experimental measurements confirmed correct operation of the concept. The proposed coupler shows strong potential for applications in fiber-optic sensing and optical communications. Full Text: PDF References W. Chen et al., "Applications and Development of Multi-Core Optical Fibers", Photonics 11, 270 (2024). CrossRef J. Sun, W. Huang, A. Lorenz, M. Zeisberger, and M. A. Schmidt, "Tunable metafibers: remote spatial focus control using 3D nanoprinted holograms on dual-core fibers", Light Sci. Appl. 14, 237 (2025). CrossRef M. Khosravi, T. Wieduwilt, M. Zeisberger, A. Lorenz, and M.A. Schmidt, "Advanced remote focus control in multicore meta-fibers through 3D nanoprinted phase-only holograms", Nat. Commun. 16, 507 (2025). CrossRef C. Liu, L. Niu, K. Wang, and J. Liu, "3D-printed diffractive elements induced accelerating terahertz Airy beam", Opt. Express 24, 29342 (2016). CrossRef R.D. Muelas-Hurtado, J.L. Ealo, J.F. Pazos-Ospina, and K. Volke-Sepúlveda, "Generation of multiple vortex beam by means of active diffraction gratings", Appl. Phys. Lett. 112, 084101 (2018). CrossRef P. Komorowski, M. Kurowska, M. Kaluza, P. Czerwińska, P. Zagrajek, and A. Siemion, "Neural Network-Based Design of Two-Focal-Spot Terahertz Diffractive Optical Elements", IEEE Trans. Terahertz Sci. Technol. 14, 228 (2024). CrossRef M. Kaluza, P. Komorowski, M. Surma, A. Nieradka, P. Zagrajek, and A. Siemion, "Advanced diffractive optical elements implementing multiple-input spatial multiplexing of terahertz radiation", Opt. Lasers Eng. 184, 108606 (2025). CrossRef M. Surma, M. Kaluza, P. Komorowski, and A. Siemion, "Segmentation of THz holograms for homogenous illumination", Sci. Rep. 14, 12733 (2024). CrossRef Y. Luo, D. Mengu, N. T. Yardimci, Y. Rivenson, M. Veli, M. Jarrahi, and A. Ozcan, "Design of task-specific optical systems using broadband diffractive neural networks", Light Sci. Appl. 8, 112 (2019). CrossRef A. Siemion, "Terahertz Diffractive Optics—Smart Control over Radiation", J. Infrared Millim. Terahertz Waves 40, 477 (2019). CrossRef J. Suszek et al., "Evaluation of the shadow effect in terahertz kinoform gratings", Opt. Lett. 38, 1464 (2013). CrossRef H. Wang et al., "Two-photon polymerization lithography for imaging optics", Int. J. Extreme Manuf. 6, 042002 (2024). CrossRef H. Wang et al., "Bio-Inspired Semi-Active Safeguarding Design with Enhanced Impact Resistance via Shape Memory Effect", Adv. Funct. Mater. 33, 2214211 (2023). CrossRef O. Yermakov et al., "Fiber-based angular demultiplexer using nanoprinted periodic structures on single-mode multicore fibers", Nat. Commun. 16, 2294 (2025). CrossRef Z. Li et al., "Doughnut beam shaping based on a 3D nanoprinted microlens on fiber tip", Opt. Laser Technol. 167, 109798 (2023). CrossRef M. Kaluza, P. Komorowski, A. Nieradka, P. Zagrajek, and A. Siemion, "Implementing Terahertz Spatial Multiplexing and Frequency Demultiplexing Systems Using Diffractive Optical Elements for 6G Telecommunications Applications", IEEE Trans. Microw. Theory Techn. 73, 6037 (2025). CrossRef M. Sypek, "Light propagation in the Fresnel region. New numerical approach", Opt. Commun. 116, 43 (1995). CrossRef
In this research, we provide the outcomes of spectral calculations and selected characteristics of the NLC homologous series of cyanobiphenyls (nCB) and phenylcyclohexanes (nPCH) within the frequency range of 0.4–7.6 THz. Geometry optimizations, assessments of harmonic frequencies, and calculations of intensity were performed utilizing Scigress – Molecular Modelling Software developed by Fujitsu. The numerical analyses were executed following the standard DFT procedure, employing the B88-LYP functional and DZVP basis sets. The results obtained for the absorption spectra, along with physical parameters such as dielectric permittivity, refractive index, and birefringence, are detailed herein. Notably, we demonstrate that the results align well with the referenced experimental findings. Full Text: PDF References J. Parka, K. Sielezin, "0.3-10.0 THz spectra for chosen liquid crystal molecules - simulation and physical properties", Mol. Cryst. Liq. Cryst., 657, 66 (2017). CrossRef K. Sielezin, R. Kowerdziej, J. Parka, "Simulations of some physical parameters of homologous series of nBT and nCHBT at 0.3-20.0 THz", Liq. Cryst., 1563918, 1 (2018). CrossRef Z. Chen, L. Jiang, H. Ma, "Calculation on frequency and temperature properties of birefringence of nematic liquid crystal 5CB in terahertz band", Chem. Phys. Lett., 645, 205 (2016). CrossRef Z. Chen, Y. Jiang, L. Jiang, H. Ma, "Terahertz absorption spectra and potential energy distribution of liquid crystals", Spectrochim. Acta A Mol. Biomol. Spectrosc. 153, 741 (2016). CrossRef Z. Chen, Y. Jiang, L. Jiang, H. Ma, "Molecular vibration mode assignment of nematic liquid crystal 5CB on Terahertz spectra", Liq. Cryst., 42(7), 947 (2015). CrossRef N. Vieweg, M. A. Celik, S. Zakel, V. Gupta, G. Frenking, M. Koch, "Terahertz Absorption of Nematic Liquid Crystals", J. Infrared Milli Terahertz Waves 35, 478 (2014). CrossRef P. Friebel, D. R. Galimberti, M. Savoini, L. Cattaneo, "Unveiling Low THz Dynamics of Liquid Crystals: Identification of Intermolecular Interaction among Intramolecular Modes", J. Phys. Chem. B 128, 596 (2024). CrossRef Molecular Modelling Software SCIGRESS, Fujitsu Limited, Tokyo, Japan, (2016), DirectLink R. Kowerdziej, L. Jaroszewicz, M. Olifierczuk, J. Parka, "Experimental study on terahertz metamaterial embedded in nematic liquid crystal", Appl. Phys. Lett., 106(9), 092905 (2015). CrossRef M. Olifierczuk, R. Kowerdziej, L. Jaroszewicz, M. Czerwinski, J. Parka, "Numerical analysis of THz metamaterial with high birefringence liquid crystal", Liquid Crystals, 39(6), 739 (2012). CrossRef R. Kowerdziej, T. Stańczyk, J. Parka, "Electromagnetic simulations of tunable terahertz metamaterial infiltrated with highly birefringent nematic liquid crystal", Liquid Crystals, 42(4), 430 (2015). CrossRef J. Parka, S. Kłosowicz, "16th Topical Meeting on the Optics of Liquid Crystals", Phot. Lett. Poland, 7(4), 90 (2015). CrossRef U. Chodorow, J. Parka, O. Chojnowska, "Liquid Crystal Materials in THz Technologies", Phot. Lett. Poland, 4(3), 112 (2015). CrossRef
