Prism Coupling Method Research Articles

Planar and ridged waveguide preparation on erbium pre-implanted fused silica by multi-energy helium ion implantation and femtosecond laser ablation

Ion implantation stands as a highly competitive technique for fabricating optical waveguide structures within photoelectric materials. In this work, both planar and ridge waveguides have been successfully realized on fused silica. The fabrication process begins with the implantation of erbium ions into fused silica, utilizing an energy of 400 keV and a fluence of 5×1015ions/cm2 to produce a fluorescence effect. Following this, helium ions are implanted at varying energies −450, 500, and 550 keV-with a consistent fluence of 3.2×1016ions/cm2 to create a planar waveguide structure. Subsequently, the ridge waveguide is meticulously prepared through the application of laser ablation, leveraging the pre-existing planar waveguide as a foundation. The guide mode of the planar waveguide is characterized at a wavelength of 632.8 nm using the prism coupling method. Additionally, the near-field light intensity distribution at the same wavelength is assessed via the end-face coupling technique and further analyzed using the finite-difference beam propagation method. To substantiate the practical utility of these waveguides, measurements of the propagation loss and fluorescence properties are conducted.

High spatial resolution surface plasmon resonance imaging using a plasmonic chip.

The surface plasmon resonance (SPR) technique has been widely applied to biosensing technologies for the rapid quantification of biomolecules without enzyme and fluorescent labeling. However, the conventional prism-coupling SPR method generally has a detection area of a few mm2, and the large contribution of the background signal forms a barrier to highly sensitive detection. Based on a highly spatially resolved SPR method, the present study constructed a scanning GC-SPR imaging instrument using an objective lens with a high numerical aperture and a plasmonic chip that could be used for grating-coupled SPR. Focusing light on the diffraction limit can suppress background signals and improve detection sensitivity. SPR imaging can also be performed by scanning a focal spot. Using this method, the refractive index of a mixture of water and dimethyl sulfoxide was measured with a detection accuracy of 2.43 × 10-3 RIU. Polydopamine films prepared with a thickness of <5nm were also measured, and each film thickness was evaluated with high sensitivity from the effective refractive index detected in a small area of <1 µm2.

Formation of optical planar waveguides on fused quartz by MeV ion implantation

AbstractThe optical losses and the refractive index change of optical planar waveguides formed by MeV ion implantation were correlated with the experimental ion implantation parameters. Direct ion implantation was performed by means of carbon, silicon and copper ion beams impinging on the substrate surface at normal incidence. The ions were accelerated at energies ranging from 3 to 12 MeV with fluences varying from 1 × 1012 to 2 × 1016 ion/cm2, according to the type of implanted ion. The modification of the substrate refractive index due to the ion irradiation‐induced damage was evaluated using the prism coupler method, and the refractive index profiles were determined by means of a reconstruction method using a multilayer structure approximation. The guiding properties of the waveguides were analysed using the fibre‐coupling technique to determine both the optical transmission and transversal modes at 635 nm. The main practical relevance of our research is the obtention of high‐quality waveguides at low current density MeV ion implantation (≤80 nA/cm2) without post‐implantation annealing.

Damage, waveguide, and electrical properties in (La, Sr)(Al, Ta)O3 single crystal irradiated with carbon ions

The (La, Sr)(Al, Ta)O3 crystal was irradiated via 20.0 MeV C ion with fluence of 1.0×1015ions/cm2. The Rutherford backscattering (RBS)/channeling spectra, the hardness and elastic modulus as continuous functions of the depth, and X-ray diffraction (XRD) are used to analyze the irradiation damage, hardness, and structural changes in the near-surface area of samples. Prism coupling and end-face coupling methods were used to study the changes of optical waveguide properties under different annealing conditions. Considering the potential applications of low-loss waveguide structure in photoelectric sensors, electrical properties of (La, Sr)(Al, Ta)O3 samples were studied as an important detection indicator of sensors.

Optical and magnetic properties in well and barrier ZnS waveguides formed by MeV Ni and Cu ion implantation

Well and barrier waveguides were fabricated in zinc sulfide (ZnS) single crystals via nickel (Ni) and copper (Cu) ion implantation. Elastic collisions between the implanted ions and target nuclei were reconstructed using SRIM software. The prism coupling and end-face coupling methods were applied to capture the dark-mode spectrum and near-field intensity distributions, respectively, at 633 nm. The absorption spectra from the UV to visible band of the ZnS crystals before and after Ni and Cu ion implantation were collected on a spectrophotometer. Magnetic properties at room temperature were evaluated under a magnetic field of 3T.

Characterization of electro-optic coefficients r13, r23 and r33 in single crystalline BaTiO3 thin films

We report experimental characterization of DC electro-optic coefficients r13, r23 and r33 in thin film single crystalline BaTiO3 on DyScO3. The epitaxial BaTiO3 thin film is sandwiched between a SrRuO3 bottom electrode and an indium tin oxide (ITO) top electrode. We characterize the DC electro-optic coefficients r13, r23, and r33 by the prism coupling method at 636.6 nm for the BaTiO3 thin film. The results show the DC coefficients r13 = 4.2 pm/V, r23 = 4.6 pm/V and r33 = 9.0 pm/V.

Optical properties of He+-implanted and diamond blade-diced terbium gallium garnet crystal planar and ridge waveguides

Terbium gallium garnet (Tb3Ga5O12, TGG) crystal can be used to fabricate various magneto-optical devices due to its optimal Faraday effect. In this work, 400-keV He+ ions with a fluence of 6.0 × 1016 ions/cm2 are irradiated into the TGG crystal for the planar waveguide formation. The precise diamond blade dicing with a rotation speed of 2 × 104 rpm and a cutting velocity of 0.1 mm/s is performed on the He+-implanted TGG planar waveguide for the ridge structure. The dark-mode spectrum of the He+-implanted TGG planar waveguide is measured by the prism-coupling method, thereby obtaining the relationship between the reflected light intensity and the effective refractive index. The refractive index profile of the planar waveguide is reconstructed by the reflectivity calculation method. The near-field light intensity distribution of the planar waveguide and the ridge waveguide are recorded by the end-face coupling method. The He+-implanted and diamond blade-diced TGG crystal planar and ridge waveguides are promising candidates for integrated magneto-optical devices.

Optical properties and thermal stability of the H+-implanted Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass waveguide

Abstract Optical waveguides play a vital role in the manufacture of various optical devices due to their unique performances and high-degree integration. We report on the preparation and characterization of the planar waveguides in the Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass. The waveguide was formed by the 400 keV H+-ion implantation with a dose of 8 × 1016 ions/cm2. Its thermal stability was studied by annealing at 260°C for 1 h. The changes in the nuclear energy loss with the implantation depth were simulated by the stopping and range of ions in matter (SRIM 2013). The dark-mode characteristics of the waveguide were measured by the prism coupling method. The refractive index distribution of the optical waveguide was reconstructed by the reflectivity calculation method. The modal profile of the waveguide structure was calculated by the finite-difference beam propagation method (FD-BPM). The thermally stable proton-implanted Dy3+/Tm3+-codoped GeS2–Ga2S3–PbI2 chalcohalide glass waveguide is expected to be applied in mid-infrared integrated optical devices.

The effect of gamma-ray irradiation on polycarbonate sheets

In our study, we report on the effect of gamma-ray irradiation on four types of polycarbonate sheets. We used the panoramic gamma-radiation facility with 60Co source with applied doses from 1.38 to 100.50 kGy with the radiation dose rate 66.6 ± 6.3 Gy/h. To get knowledge on the needed properties, the prism coupling method was used for refractive indices measurement at six wavelengths (532.0, 654.2, 846.4,1308.2, 1549.1 and 1652.1 nm) and Sellmeier approximation with an infrared correction was used to estimate the refractive indices from 500 to 1700 nm. The transmission spectra were measured in the spectral range from 250 to 2150 nm and absorption coefficient and band gap Eg were calculated from transmission spectra. The chromaticity coordinates and influence of the gamma-irradiation were also studied. Our results proved that materials such as these can be used in gamma-radiation-exposed environments for optical components such as digital camera lenses, optical lenses, mirrors, prisms, optical waveguides, etc.

Performance simulation of terahertz waveguide resonance biochemical sensor based on nanoporous gold films

A highly sensitive terahertz (THz) waveguide resonance biochemical sensor is designed and simulated. The sensor consists of a silicon prism, a dielectric layer and a nanoporous gold film. The nanoporous gold film acts as both a THz waveguiding layer and a biochemical molecular enrichment layer, which can enhance the interaction between the THz waveguide mode and the adsorbed biochemical molecules, consequently improving the sensor’s sensitivity. When the THz transverse electric (TE) or transverse magnetic (TM) modes are excited by the prism-coupling method, the THz absorption of the nanoporous gold film results in the sharp resonance dips in the THz reflection spectrum. The resonance frequencies of the THz waveguide modes and the sensitivity to either liquid refractive index (RI) or adsorbed molecules can be determined with the measured reflection spectra, and the sensor’s sensitivity and its figure of merit (FOM) can be improved by adjusting the thickness and RI of the dielectric layer. The simulation results at 45º incidence angle indicate that the resonance frequencies of the TE and TM modes of the sensor linearly change with increasing either liquid RI or the amount of adsorbed molecules, and the RI sensitivity and the FOM with the TM mode are 13.42 THz/RIU and 167.70/RIU, respectively. Compared with the TM mode, the TE mode has a lower sensitivity to lqiuid RI but a high sensitivity to adsorbed molecules. The reason for these differences is that with the TE mode the evanescent field penentrating out of the nanopous gold film is weaker than that with the TM mode.

Monomode Optical Waveguide Achieved by Lattice Damage in Yttria-Stabilized Zirconia Crystal Induced from Energetic Oxygen Irradiation

With valuable physicochemical properties, yttria-stabilized zirconia crystal has promising advantages in optical applications. In this paper, the waveguide effect is observed in yttria-stabilized zirconia crystal irradiated by energetic oxygen ions. The waveguide properties and the field intensity are analyzed using prism and end-face coupling method arrangements, and the results show that monomode is found in the near-surface region and the light beam can be well confined in the waveguide structure, which shows refractive index distribution of the barrier-wall and enhanced-well type. The lattice damage induced by irradiation is investigated by the Rutherford backscattering/channeling experiment and high-resolution X-ray diffraction techniques. The simulation results are in good agreement with the experimental data.

Lattice structures and optical properties of Ce:LYSO crystal waveguides with implanted C, Si and Cu ions

We report on the lattice structures and optical properties of Ce:LYSO crystal waveguides implanted with C, Si and Cu ions at 6 MeV. SRIM software was used to reconstruct the elastic collisions between the implanted ions and target nuclei. The maximum structural changes were induced by the Cu-ion implantation, as determined by XRD and Raman spectra. Photoluminescent and absorption spectra were used to study the optical properties of Ce3+ ions in the Ce:LYSO waveguides. Prism-coupling and end-face coupling methods, respectively, were used to measure the guiding modes and the near-field intensity distribution of light at 633 nm. Typical well + barrier waveguides were formed in the Ce:LYSO crystals implanted by C, Si and Cu ions, which will be a interest application in integrated optical devices.

Investigation on the bulk crystal growth, crystalline perfection, refractive index and piezoelectric properties of borate single crystals for piezoelectric and electro-optic applications

Low solubility potassium pentaborate tetrahydrate (KB5), ammonium pentaborate tetrahydrate (AB5) and mixed (KAB5) single crystals have been grown by the Sankaranarayanan-Ramasamy (SR) method. The crystal structures and space groups have been confirmed by powder XRD analysis. The direction of the grown crystal was confirmed by the back reflection X-ray Laue pattern. The crystalline perfection (CP) of the crystals have been evaluated using HRXRD studies. The transmittance spectra of the grown crystals were recorded by UV–Vis-NIR transmission studies showing that all the crystals have 90% transmittance in the entire visible region and found that the crystals' cut off wavelengths were below 200 nm. The optical studies such as refractive index (RI) and birefringence interferometry (BI) were reported. The RI for five different wavelengths of KB5, AB5 and KAB5 crystals were analyzed using the prism coupling method (PCM). Electromechanical behavior of the grown crystals was observed using piezoelectric coefficient (d33) measurement. Vickers Microhardness (VMH) measurement carried out at 30 °C shows increased hardness as the load increases.

Broadband mode-selective couplers based on tapered side-polished fibers.

We propose the broadband mode-selective coupler (MSC) formed with a side-polished six mode fiber (6MF) and a tapered side-polished small core single-mode fiber (SC-SMF) or an SMF. The MSCs are designed to allow the LP01 mode in the SC-SMF and SMF to completely couple to the LP01, LP11, LP21, LP02, LP31, LP12 modes in the 6MF over a broadband wavelength range. The phase-matching conditions of the MSCs are satisfied by tapering the SC-SMF and SMF to specific diameters. The tapered fibers are side-polished to designed residual fiber thickness using the wheel polishing technique. The effective indices of the side-polished fibers are measured with the prism coupling method. The MSCs provide high coupling ratio and high mode purity. High coupling efficiencies in excess of 81% for all the higher-order modes are obtained in the wavelength range 1530-1600 nm. For the LP01, LP11, LP21, LP02, LP31, LP12 MSCs at 1550 nm, the coupling ratios are 96.2%, 99.8%, 89.5%, 85.0%, 90.9%, 96.1%, respectively, and the mode purity of the MSCs is higher than 88.0%. The loss of the MSCs is lower than 1.8 dB in the wavelength range 1530-1600 nm. This device can be applied in broadband mode-division multiplexing transmission systems.

Investigation of novel optical and waveguide characteristics for an air–graphene–LiNbO3 system

The optical characteristics of a planar thin film waveguide system composed of air–graphene–LiNbO3 have been investigated. Monolayer or bilayer graphene of high quality are characterized by Raman spectroscopy, scanning electron microscopy and atomic force microscopy. The refractivity and reflectivity of the air–graphene–LiNbO3 system are measured experimentally and compared with those of a LiNbO3 waveguide by the prism coupling method. The reflectivity shows an overall decrease due to the lower transmittance for graphene on the LiNbO3 substrate. The refractivity increases significantly at the wavelength of 1540 nm, which may be attributed to the generation of graphene surface plasmons excited by infrared radiation. A shaped air–graphene–LiNbO3 waveguide is designed and simulated by Mode Solutions. The distribution of an optical field is performed and analyzed. The preparation of the proposed air–graphene–LiNbO3 structure incorporates the commonly used chemical vapor deposition and thin film transfer techniques, and is compatible with existing optoelectronic integration processes, which can be employed for building various optical integrated devices.

Lithium niobate planar and ridge waveguides fabricated by 3 MeV oxygen ion implantation and precise diamond dicing

We report on the fabrication and optimization of lithium niobate planar and ridge waveguides at the wavelength of 633 nm. To obtain a planar waveguide, oxygen ions with an energy of 3.0 MeV and a fluence of 1.5×1015 ions/cm2 are implanted in the polished face of LiNbO3 crystals. For planar waveguides, a loss of 0.5 dB/cm is obtained after annealing at 300°C for 30 min. The ridge waveguide is fabricated by the diamond blade dicing method on optimized planar waveguides. The guiding properties are investigated by prism coupling and end-face coupling methods.

Growth of 1, 3, 5 - Triphenylbenzene single crystal by modified vertical Bridgman method and its characterization for scintillation application

1, 3, 5-triphenylbenzene (TPB) single crystal (length 100 mm and diameter 10 mm) has been successfully grown for the first time by the modified vertical Bridgman technique (VBT). This method is developed for the growth of crystals (changing the translation system using gear setup), with enhanced quality. Physical, optical and scintillation properties such as crystalline nature, thermal stability, transmittance, radioluminescence and lifetime were investigated. The polished TPB sample has a good transmission (80%) in the wavelength range between 300 and 1500 nm. The thermal properties of the grown crystal were analyzed by thermogravimetric and differential thermal analyses. Measurements of the refractive index of TPB crystal were made using the prism coupling method at five different wavelengths in the range between 407 and 1551 nm. Birefringence study reveals that the grown crystal has good optical homogeneity. Scintillation properties such as radioluminescence using Sr-90 as a source and decay time were also investigated.

Nonlinear optical process of second-order nonlinear optical susceptibility χ133(2) in an organic nonlinear optical crystal DAST.

A large unexamined second-order nonlinear optical (NLO) process is found in a 4-N,N-dimethylamino-4'-N'-methyl stilbazolium tosylate (DAST) crystal, which has a large figure of merit among NLO crystals. In second-order NLO processes using a DAST crystal, the χ111(2) process of light excitation is commonly used, involving a-axis polarized light excitation with light generation of a-axis polarized light. However, there have been few studies of other second-order NLO susceptibility processes to date. In this Letter, terahertz (THz) wave generation via second-order NLO processes based on the χ133(2) second-order NLO susceptibility of the DAST crystal was investigated. By adjusting the polarization direction of the excitation light using a prism-coupled Cerenkov phase-matching method, efficient generation of THz waves was achieved using a process involving χ133(2). The magnitude of the NLO constant χ133(2) estimated from the THz intensity ratio was 77.8 pm/V. These results indicate that prism-coupled Cherenkov phase matching can be used to identify undiscovered NLO processes for NLO crystals.

Investigation on the growth rate, crystalline perfection, refractive index, Z-scan and electrical characteristics of Z- cut imidazolium l-tartrate single crystal

Abstract Single crystal of imidazolium l -tartrate (IMLT) was grown by the Sankaranarayanan-Ramasamy method. The IMLT crystal system and space group were confirmed by single crystal X-ray diffraction (XRD) studies. X-ray Laue back reflection has been used to find out the orientations of the grown crystals. HRXRD studies revealed that the grown crystal shows good crystalline perfection with full-width-at-half-maximum ~23 arc-s. The UV–Vis–NIR studies show that the grown crystal has good transmission in the entire visible region. The refractive index (RI) and relative birefringence were measured for the first time to the best of our knowledge. Refractive index measurement was done by the prism coupling method. The observed variation of RI and birefringence (Δn) along principal directions depict IMLT belongs to a biaxial crystal system. Birefringence interferometry shows that the grown crystal has good refractive index homogeneity. The temperature dependent pyroelectric coefficients of IMLT have been determined. The nonlinear optical (NLO) properties of the IMLT crystal such as absorption coefficient (β), refractive index (n2) and the third order NLO susceptibility (χ(3)) have been analyzed by Z-scan measurement at 632.8 nm wavelength. Laser damage threshold (LDT) value of the SR method grown crystal has been determined at 532 nm by using a nanosecond second harmonic of Nd:YAG laser. Dislocation density of the SR method grown IMLT crystal was calculated by chemical etching studies. The IMLT crystal grown from the SR method has been found to have high laser damage stability, high piezoelectric coefficient and low dislocation density.

Fabrication of ion-sliced yttrium-aluminum-garnet thin films on silica by He+ implantation and Cu–Sn bonding

The fabrication of sub-micron-thickness ion-sliced yttrium-aluminum-garnet thin films on silica is performed by He + implantation and the Cu–Sn bonding. The formation of blisters on He-ion-implanted YAG crystals caused by thermal annealing is investigated. YAG thin films with an area of approximately 6 mm × 5 mm are produced. The implanted YAG crystals and fabricated YAG thin films are investigated using optical, transmission electron, and scanning electron microscopy, as well as prism-coupling methods. A YAG thin film with a low-refractive-index silica cladding can be used as a waveguide to manufacture photonic components with high refractive index contrast. • We report the fabrication of ion-sliced YAG thin films on SiO 2 for the first time. • The blistering behavior is investigate. • A sub-micron-thickness YAG thin film with an area of 6 × 5 mm is fabricated. • A YAG thin film on SiO 2 cladding layer can act as a slab waveguide.