Holographic Lithography Method Research Articles

Two-dimensional liquid crystal polarization grating via linearly polarized light modified multi-beam polarization interferometry.

Holographic lithography is widely used as an effective approach for two-dimensional (2D) photonic crystal fabrication. However, for the fabrication of 2D polarization structures based on photoaligned liquid crystals (LCs), holographic lithography method is limited. The fabrication requires full coverage of light intensity, 2D chiral distribution and continuously varying polarization direction, which could be hardly guaranteed by multi-beam interference of circularly polarized light (CPL). Herein, we introduce a linearly polarized light (LPL) into a three-CPL interference configuration to improve the interference field and fulfill the critical requirement. The introduced LPL intensity is chosen to be 1/5 of the CPL to guarantee both full coverage of light intensity and well photoalignment defined LC directors. Moreover, the introduction of the weak LPL into multiple CPL interference is shown to give little disturbance to the desired diffraction properties.

Fractional-topological-charge-induced vortex birth and splitting of light fields on the submicron scale

The formation and dynamics of fractional vortex charge in orbital-angular-momentum states is experimentally investigated. The holographic lithography method developed in this work may be effectively applied to study other structured matter waves.

As2Se3기반 Resistive Random Access Memory의 채널 직선화를 통한 신뢰성 향상

Resistive random access memory (ReRAM) of metallic conduction channel mechanism is based on the electrochemical control of metal in solid electrolyte thin film. Amorphous chalcogenide materials have the solid electrolyte characteristic and optical reactivity at the same time. The optical reactivity has been used to improve the memory switching characteristics of the amorphous As2Se3-based ReRAM. This study focuses on the formation of holographic lattices patterns in the amorphous As2Se3 thin film for straight conductive channel. The optical parameters of amorphous As2Se3 thin film which is a refractive index and extinction coefficient was taken by n&k thin film analyzer. He-Cd laser (wavelength: 325 nm) was selected based on these basic optical parameters. The straighten conduction channel was formed by holographic lithography method using He-Cd laser. Ag + ions that photo-diffused periodically by holographic lithography method will be the role of straight channel patterns. The fabricated ReRAM operated more less voltage and indicated better reliability.

Efficient Platform for Flexible Engineering of Superradiant, Fano-Type, and Subradiant Resonances

Delicate control of the surface plasmon resonance (SPR) line shapes is crucial for the development of nanoplasmonics with dedicated applications. In this paper, we develop a method to fabricate large-scale periodic structures with significantly different plasmonic properties by the holographic lithography method. We show that SPR line shapes can be controllably engineered from a broad superradiant line shape to an asymmetrical Fano-type resonance, as well as an ultranarrow subradiant mode, which are clearly correlated with the structural parameter (morphology) of the fabricated structures. The wavelength of the SPR band can be tuned from the visible to near-infrared region by changing the incident angle. The nanostructures fabricated by the present method show a clear correlation between the morphology of plasmonic structures and SPR line shapes, which can serve as an efficient platform for engineering SPR line shapes for specific applications. Most importantly, the capability to produce structures of lar...

The Wavelength-Locking of High-Power 808 nm Semiconductor Laser

A distributed feedback (DFB) laser of 808 nm is produced in this paper whose optical power is 2 W, cavity length is 3 mm, and injecting width is 200 μm. A second-order grating formed into an InGaP/GaAs/InGaP multilayer structure provides the optical distributed feedback. The holographic lithography method is adopted to make Bragg gratings in p-waveguide layer (Λ = 240 nm) of the GaAs epitaxial wafers. The best experimental conditions are determined by analyzing the surface morphology and three-dimensional holographic grating. In addition, the output power data and wavelength of the distributed feedback laser emitting at different temperatures are presented. And the wavelength varies with temperature at a rate of 0.062 nm/K. Finally, the conclusion is drawn that this kind of DFB laser has a better temperature stabilized wavelength and narrower line width.

Erratum: Fabrication of large-scale photonic phased array using a holographic lithography system

A holographic lithography method for fabricating large-scale photonic phased array is presented. The large-scale array could be gen- erated using a specially designed holographic optical element and the period could be decreased by half with the help of a half-wave plate. This method provides a convenient way to obtain the photonic array with a smaller period without shortening the recording wavelength. MATLAB simulations and primary experimental results have demonstrated that the phase modulation and nonlinear photoresist response played collectively significant roles in tuning the distribution of the array. The large-scale photonic phased array with a smaller period is an ideal candidate as a Raman substrate. © 2013 Society of Photo-Optical Instrumentation

Electrical Characteristics of Ge25Se75 Thin Films by Ag Ion Doping Methods for Resistance Random Access Memory Applications

Chalcogenide thin films have characteristics of both electric switching and individual optical reactivity. The resistance random access memory (ReRAM) using amorphous chalcogenide materials is based on the electrochemical control of photodiffused metal ions in chalcogenide thin films. In this study we focus on the formation of a straight filament pattern in Ge25Se75 thin films by changing the doping method for Ag ions. Ag photodissolution was performed by the general method (UV exposure) and a holographic lithography method [using He–Ne laser (632.8 nm)]. We measured the electrical characteristics of each device. Improved results were obtained with the induced straight filament pattern device. In the device patterned straightly, operation voltage and reliability were improved.

Fabrication of micro-tube arrays in photopolymer SZ2080 by using three different methods of a direct laser polymerization technique

In this paper we demonstrate femtosecond laser fabrication of micro-tubes with a height of several tens of micrometers in the photopolymer SZ2080 by three different methods: direct laser writing, using the optical vortex beam and holographic lithography. The flexibility of direct laser writing and dramatic increase of production efficiency by applying the vortex-shaped beam and four-beam interference approaches are presented. Sample arrays of micro-tubes were successfully manufactured applying all three methods and the fabrication quality as well as efficiency of the methods is compared. The processing time of a single micro-tube with 60 µm height and 3 µm inner radius is reduced 400 times for the holographic lithography technique and 500 times for the optical vortex method compared with the direct laser writing technique. The processing time of a micro-tube array containing 400 micro-tubes is the shortest for the holographic lithography method but not for the optical vortex method as in the case of a single micro-tube, because the holographic lithography method does not require time for sample translation. Additionally, the holographic lithography enables manufacturing of the whole micro-tube array by a single exposure. Although point-by-point photo-structuring ensures unmatched complexity of manufactured microstructures, employing nowadays high repetition rate amplified femtosecond lasers combined with beam shaping or several beam interference can envisage industrial applications for practical demands.

Holographically formed three-dimensional Penrose-type photonic quasicrystal through a lab-made single diffractive optical element

Large-area three-dimensional Penrose-type photonic quasicrystals are fabricated through a holographic lithography method using a lab-made diffractive optical element and a single laser exposure. The diffractive optical element consists of five polymer gratings symmetrically orientated around a central opening. The fabricated Penrose-type photonic quasicrystal shows ten-fold rotational symmetry. The Laue diffraction pattern from the photonic quasi-crystal is observed to be similar to that of the traditional alloy quasi-crystal. A golden ratio of 1.618 is also observed for the radii of diffraction rings, which has not been observed before in artificial photonic quasicrystals.

Holographic Lithography 방법을 적용한 Chalcogenide-based ReRAM(Resistance RAM) 소자의 개발에 관한 연구

In this study, we studied the nature of thin films formed by holographic photodoping chalcogenide thin films with for use in programmable metallization cell devices(PMC), a type of ReRAM. We formatted straight conduction pathway from the internal interferences of the diffraction gratings which is builded by the holographic lithography method. We investigated the resistance change of solid-electrolyte chalcogenide thin films varied in the applied voltage bias direction from about <TEX>$1\;M{\Omega}$</TEX> to several hundreds of <TEX>$\Omega$</TEX>. The switching characteristics of the devices applied holographic lithography method was more improved than ultraviolet exposure condition. As a result of improved resistance change effects, we can analogize that the diffraction gratings is a kind of pattern for straight conduction pathway formation inside the chalcogenide thin films.

포토닉 크리스탈 응용을 위한 비정질 칼코게나이드 As-Ge-Se-S 박막의 특성 연구

In this paper, we investigated the properties of chalcogenide glass thin films formed by photo-inducing for use in 1-dimensional photonic crystals. We used Ag-doped amorphous As-Ge-Se-S thin films which belongs in the chalcogenide materials having sensitive photoluminescence properties. The purpose of this experiment is to form the holographic lattice for 1-dimensional photonic crystals. The way in which photo-induce into the amorphous chalcogenide thin films is holographic lithography method. We confirmed the formation of diffraction lattice by sensing the existence of diffraction beam and measured the diffraction efficiency. The results suggest that there is an application possibility with photonic crystals.

Fabrication of Photonic Crystals by Holographic Lithography Method

In this study, we found out the new fabrication process condition for Photonic crystals(PCs). PCs were fabricated by holographic lithography(HL), instead of commonly used electron beam lithography(EBL). HL process enable periodic large area fabrication of PCs. Also this method can easily control the pitch of periodic patterns. We set up holographic lithography system by laser and some optical components. The source of light used laser of 442 nm wavelength. Photo-resist(PR) used DMI-150 model. The viscosity of PR is diluted with propylene glycol monomethyl ether acetate(PGMEA) which is solvent for DMI-150. This experiment is holographic lithography of rotated double exposure method for PCs pattern. The method use only one beam. Result data is shown by atomic force microscope(AFM), scanning electron microscope(SEM) and 3D contour image. At the this study, we conclude conditions which we need periodic structure for PCs. It is some factor. For example, incident angle, exposure time, rotation angle, etc. And we show incident angle calculation recipe for needed size of periodic patterns. We already manufacture PCs structure design and simulation tool. Nano structure of this paper’s result is applied to designed PCs patterns.

Holographic lithography of a two-dimensional hexagonal structure: Effect of beam polarization

A comparison is made between the theoretical determination of the interference contrast function with fabricated two-dimensional hexagonal structures of submicron lattice constant. Experiments were performed using a siloxane based hybrid organic–inorganic material and a holographic lithography method. Thin hybrid structured layers were fabricated and characterized for different conditions of beam polarizations between 0 ° and 90 ° . As a result, the photo patterning appears to be strongly dependent on beam polarization in accordance with theoretical predictions.

Icosahedral quasicrystals for visible wavelengths by optical interference holography

Quasicrystals, realized in metal alloys, are a class of lattices exhibiting symmetries that fall outside the usual classification for periodic crystals. They do not have translational symmetry and yet the lattice points are well ordered. Furthermore, they exhibit higher rotational symmetry than periodic crystals. Because of the higher symmetry (more spherical), they are more optimal than periodic crystals in achieving complete photonic bandgaps in a new class of materials called photonic crystals in which the propagation of light in certain frequency ranges is forbidden. The potential of quasicrystals has been demonstrated in two dimensions for the infrared range and, recently, in three-dimensional icosahedral quasicrystals fabricated using a stereo lithography method for the microwave range and direct laser writing for the IR range. Here, we report the fabrication and optical characterization of icosahedral quasicrystals using a holographic lithography method for the visible range. The icosahedral pattern, generated using a novel 7-beam optical interference holography, is recorded on photoresists and holographic plates. Electron micrographs of the photoresist samples show clearly the symmetry of the icosahedral quasicrystals in the submicron range, while the holographic plate samples exhibit bandgaps in the angular-dependent transmission spectra in the visible range. Calculations of the bandgaps due to reflection planes inside the icosahedral quasicrystal show good agreement with the experimental results.

Simulated calculation and analysis of the forbidden band for fabricating two- and three-dimensional photonic crystal structures using holographic lithography

Compared with the semiconductor and micromachining fabrication technology, the holographic lithography method offers a number of advantages, including its ability to create large volume of periodic structures through one irradiation process, the uniformity of period, and more degrees of freedom to control the structures. In this study, a multi-beam interference model is presented for predicting two-and three-dimensional photonic crystal structures through designing the beam intensities, polarization directions and phase delays. Based on plane wave expansion method, complete forbidden bands of three-dimensional photonic crystals with fcc structure are also studied. The calculated results provide a useful guide for choosing proper optical parameters to fabricate two- and three-dimensional photonic crystal structures.

Predication of multi-dimensional photonic crystal structures generated by multi-beaminterference in holographic lithography

Photonic crystals (PCs) are synthetic micro-structures which have periodic refractive indexvariations and produce photonic bandgaps similar to electronic bandgaps produced by thecrystal potentials of semiconductors. Different methods have been proposed anddemonstrated to fabricate two- or three-dimensional photonic crystal structures. Amongthem, the holographic lithography method, in which multi-beam interferenceis employed, offers a number of advantages. These include the ability to createa large volume of uniform periodic structures through an irradiation process,and more degrees of freedom to control the structures. In this study, a model ispresented for predicting the multi-dimensional photonic crystal structures formedusing multi-beam interference. Various parameters, including beam propagationand polarization directions, beam intensities, and phase shifts are considered.Calculations have been carried out to simulate two four-beam configurations whichhave been popularly used in the fabrication of photonic crystals. It has beendemonstrated that the contours of the interference pattern are related to thepolarization states, the intensity ratios among the four beams, and the phasedelays. Therefore, by controlling the beam intensities, polarization directions,and phase delays, different structures can be obtained. The results presented inthis study provide a useful guide for choosing various optical parameters andselecting suitable photoresists to fabricate 2D and 3D photonic crystal structures.

Photonic crystal with diamondlike structure fabricated by holographic lithography

In this letter, we report a diamondlike structure. Our theoretical analysis reveals that a large complete band gap exists between the second and third bands with only a very low refractive index is needed (n⩾2.05) to open the complete band gap for this inverse structure. Large-scale and high-quality three-dimensional structures with this diamondlike symmetry are fabricated by a holographic lithography method using four laser beams incident from the same half-space. The beam geometry is similar to that for the face-centered cubic (fcc) structure except that the central beam is circularly polarized and the polarizations of the three outer beams must be optimized, which is critical to construct this diamondlike interference pattern.

Three-dimensional photonic crystals fabricated by visible light holographic lithography

In this report, we present three-dimensional photonic crystals fabricated by a four-beam holographic lithography method using visible photoinduced polymerization. High-quality face-centered-cubic single crystals with a large range of polymeric matrix volume fraction were fabricated using optimal conditions obtained from computer simulations. Optical measurements of the crystals showing photonic band-gap-like behavior are presented for different polymeric matrix volume fractions.