In this paper, we study tunable holographic lithography using an electrically addressable spatial light modulator as a programmable phase mask. We control the phases of interfering beams diffracted from the phase pattern displayed in the spatial light modulator. We present a calculation method for the assignment of phases in the laser beams and validate the phases of the interfering beams in phase-sensitive, dual-lattice, and two-dimensional patterns formed by a rotationally non-symmetrical configuration. A good agreement has been observed between fabricated holographic structures and simulated interference patterns. The presented method can potentially help design a gradient phase mask for the fabrication of graded photonic crystals or metamaterials.
For the first time, to the authors' best knowledge, this paper demonstrates the digital, holographic fabrication of graded, super-basis photonic lattices with dual periodicity, dual basis, and dual symmetry. Pixel-by-pixel phase engineering of the laser beam generates the highest resolution in a programmable spatial light modulator (SLM) for the direct imaging of graded photonic super-lattices. This technique grants flexibility in designing 2-D lattices with size-graded features, differing periodicities, and differing symmetries, as well as lattices having simultaneously two periodicities and two symmetries in high resolutions. By tuning the diffraction efficiency ratio from the SLM, photonic cavities can also be generated in the graded super-lattice simultaneously through a one-exposure process. A high quality factor of over 1.56 × 10 for a cavity mode in the graded photonic lattice with a large super-cell is predicted by simulations.
In this paper, we present an achievable gradient refractive index in bi-continuous holographic structures that are formed through five-beam interference. We further present a theoretic approach for the realization of gradient index devices by engineering the phases of the interfering beams with a pixelated spatial light modulator. As an example, the design concept of a gradient index Luneburg lens is verified through full-wave electromagnetic simulations. These five beams with desired phases can be generated through programming gray level super-cells in a diffractive spatial light modulator. As a proof-of-concept, gradient index structures are demonstrated using synthesized and gradient phase patterns displayed in the spatial light modulator.
In this paper, we present a method for the mathematically formulated phase engineering of interfering laser beams through a spatial light modulator for a holographic fabrication of graded photonic lattices. The desired phases can be programmed at specific locations by assigning gray levels in cellular structures. The method is demonstrated by embedding single-lattice structures or missing lattices in dual-lattice periodic photonic structures. The demonstrated method can be potentially combined with the coordinate transformation technique in transformation optics for the fabrication of graded photonic devices.
This paper presents a holographic formation of compound photonic crystal and nano-antenna templates through a reflective optical element based laser interference. The reflective optical element consists of four Si facets where a circularly polarized single beam impinges at the Brewster angle and is reflected into four linearly s-polarized beams for the inference lithography. By tuning the phase delay in one of the interfering beams, dual-lattice photonic crystal, and nano-antenna templates are fabricated and compared with theoretic simulation. The design conditions for the nano-antenna formation are discussed.
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