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Micro-nanoscale metrology for reference material size from speckle pattern images
(2026-03-05)
Sirikarntayuprakit, Pakkhanan
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Plaipichit, Suwan
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Ngansalung, Benjarat
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Buranasiri, Prathan
Recently, the fabrication of micro- and nanoscale materials has become necessary in daily life. The sizes and compositions of those materials need to be explored, as the products will be used in other industries. Therefore, micro-nanoscale metrology is necessary for quality control, as some processes require the use of reference materials for comparing the size of industrial micro-nano-sized products. This study investigates the feasibility of using laser speckle imaging. Since the laser speckle setup is relatively inexpensive, the system is a good choice for installation in small factories. Combined with the Gray-level Co-occurrence Matrix (GLCM) analysis method, this technique has been used to compare the size of reference materials that are fabricated by the National Institute of Metrology of Thailand. Two sizes of reference materials, 100 nm and 1,000 nm, were of interest. The particles are composed of polystyrene, and their certified mean diameter and size distribution were determined using transmission electron microscopy (TEM), validated through international comparison, and served as the basis for testing the technique. Clear differences in GLCM contrast, dissimilarity, energy, and correlation were observed between the two particle sizes, reflecting their distinct scattering characteristics. The results demonstrate that speckle-based texture analysis provides a sensitive response to particle size variation, offering a promising pathway toward low-cost, non-invasive micro-nano metrology.
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Photorefractive Effect in an Imperfect Cerium Doped Barium Titanate Crystal: Reflection Grating Case
(2026-01-01)
Khotphuthon, Wasuphon
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Plaipichit, Suwan
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Suchat, Suebtarkul
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Buranasiri, Prathan
The photorefractive (PR) effect, a nonlinear optic phenomenon, occurs in materials that have electro-optic (EO) properties. When two coherent beams of light interfere with each other in a PR material, donor electrons between valence band and conduction band, caused by material impurity, absorb the photon and are excited into the conduction band and generate electron-hole pairs. This process induces a periodic electric field called a space charge field that alters the material’s refractive index due to the EO effect. In this research, we explored reflection grating (RG) in an imperfect Ce-doped BaTiO3 crystal and then showed optical image correlation using the RG. Two beam coupling was investigated using two non-Gaussian incident beams on the opposite surface of an imperfect Ce-doped BaTiO3 crystal. Light at green wavelengths from a semiconductor laser was used as the source of the incident beams and entered at certain angles relative to the crystal c-axis. Large beam coupling power was observed in both incident directions when the angle between both incident beams is at Bragg’s angle in the direction of the c-axis. The diffraction light was found to be in the same polarization as the incident beam. In addition, interesting results for the optical correlation using reflection grating were demonstrated. These results suggest that by doping BaTiO3 with cerium, strong beam coupling or photorefractive grating can be observed with certain incident writing angles on the crystal, which could be utilized in future flexible holographic devices in the future.
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DESIGNING WEAVING PATTERN AND ENGINEERING MULTILAYER STRUCTURE OF NYLON-ACRYLIC FABRIC UTILIZING IN TRIBOELECTRIC NANOGENERATOR
(2025-01-01)
Navatragulpisit, Suchanat
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Krailadsirirattna, Praophansupa
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Khwanming, Rawiwan
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Pongampai, Satana
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Plaipichit, Suwan
In the contemporary era, the textile triboelectric nanogenerator (T-TENG) has sparked interest to be a powerful energy supply for small electronic devices and electronic component in next generation of electronic textiles. Most T-TENG is developed by adding other materials to fabric or cloths that probably limit the comfortable use. Fabrication of conformable fabrics with high triboelectric outputs remains challenging. This research is firmly focused on the development of fully-fabric T-TENG by employing woven nylon-acrylic fabrics as the main contact material and designing a weaving pattern together with engineering a multi-layered structure to amplify its electrical efficiency. Based on the experimental results, different weaving patterns provided different electrical output values owing to its different contact surface areas. The matt weave pattern can yield the best electrical output regarding the extreme deformations. A further significant enhancement in T-TENG’s performance is consistent with inserting polymer intermediate layer. Adding ball-fiber and kapok serves as a synergetic charge-trapping interlayer, rendering a high triboelectricity of both open circuit voltage (VOC) and short circuit current (ISC) for 3 to 8 times higher than that of nylon-acrylic single layer. Finally, the multilayer fabric T-TENG is integrated with the long-sleeved garments and provide output enough to fully-charge the 0.22 μF and 0.33 μF capacitors together with brightening 30 LEDs. Finally, this work demonstrates a potential way with simple procedures in achieving fully-fabric T-TENG for small-scale energy sources that can harvest biomechanical energy to power electronic component for approaching the real application in E-textile systems.
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Evaluating Noise Reduction Methods for Raman Spectroscopy in Transmission and Reflection Configurations
(2024-05-01)
Sassuvun, Wasunun
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Buranasiri, Prathan
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Wicharn, Surawut
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Puttharugsa, Chokchai
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Limnonthakul, Puenisara
This work involved comparing Raman signals obtained from two different Raman spectroscopy configurations, using two distinct noise reduction methods. The excitation light source was a laser diode with a wavelength of 532 nm. A long-pass filter and focusing lens were utilized to block the excited light from the source and concentrate the Raman signals due to their weaker nature compared to the excited light signals. Light of 532 nm wavelength was blocked during green laser diode illumination using a long-pass filter. Two configurations were studied: transmission Raman spectroscopy (TRS) and reflection Raman spectroscopy (RRS). Raman signals from both configurations were compared, and the boxcar averaging and Vancouver Raman algorithm (VRA) noise reduction methods were investigated and compared. The results showed that Raman signals from the transmission configuration were higher than those from the reflection configuration, and noise signals were effectively reduced using both the boxcar averaging and VRA methods.
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Digital holography with deep learning for algae identification and classification
(2024-01-01)
Ruttanasirawit, Chinnaphat
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Plaipichit, Suwan
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Thongsuwan, Setthanun
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Thonglim, Pachara
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Phunpruch, Saranya
Recently, the characterization of marine objects, populations and biophysical interactions have become crucial within the research community. In this study, we leverage digital holographic imaging systems and deep learning networks to classify three distinct types of micro-algae: Chlamydomonas, Scenedesmus armatus, and Scenedesmus_sp-L. We employed reconstructed digital holographic images and deep learning to identify the results from both approaches. The integration of holographic imaging holds promises in replacing expensive characterization systems like AFM, x-ray diffraction, and Raman spectroscopy, offering a more costeffective solution. In our system, we utilize in-line microscopic digital holographic imaging to record and reconstruct images of the algae specimens. An essential advantage of holographic techniques is that they do not require intact samples of the specimens for effective object identification. To further enhance the process, we combined deep learning algorithms with holographic imaging, capitalizing on the advanced computers. This combination enables highly effective characterizing and classification of different types of algae. These innovative approaches pave the way for exciting advancement in marine research and monitoring.
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The Moina Gender Investigation using In-Line Digital Holographic Microscopy
(2023-01-01)
Voochaiyaphum, Bunyarit
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Thongsuwan, Setthanun
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Ruttanasirawit, Chinnapat
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Plaipichit, Suwan
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Thonglim, Pachara
The investigation of Moina was performed using in-line DHM. The reconstructed images of Moinas have been applied for investigation their surface area. Then the surface area has been used for gender investigation.
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Recursive-formula for second-harmonic generation problem in photonic hypercrystal
(2022-09-01)
Buranasiri, Prathan
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Plaipichit, Suwan
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Puttharugsa, Chokchai
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Wicharn, Surawut
In this work, we proposed a recursive-formula based on transfer-matrix method to solve problem of second-harmonic generation by obliquely incident fundamental-harmonic wave in a photonic hypercrystal, which is composed of one-dimensional periodically alternating arrangement of nonlinear hyperbolic metamaterial layer with anisotropic permittivities: ε<inf>axx</inf>, ε<inf>azz</inf> and layer thickness: a and linear dielectric layer with isotropic permittivity: ε<inf>a</inf> and layer thickness: b. This proposed formula was very simple and accurate for calculating conversion efficiency of second-harmonic generation at various incident angles of fundamental-harmonic wave and thicknesses of nonlinear hyperbolic metamaterial layer. The numerical results showed that the maximum conversion efficiency can be achieved by the strong local field confinement of fundamental-harmonic wave in the photonic hypercrystal and phase-matching due to optimal values of hypercrystal layer thickness and incident angle of fundamental-harmonic wave.
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Phase Extracting Imaging by Stacking Defocus Transport of Intensity Equation
(2022-01-01)
Plaipichit, Suwan
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Visessamit, Jakkapol
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Wicharn, Surawut
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Buranasiri, Prathan
The investigation of cells was performed using TIE. The phase imaging using a stack of low defocus intensity images has shown better results of the cell edge and shape comparing with the traditional one.
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Hybrid nanowire-hyperbolic metamaterial based broadband absorber for the visible and near-infrared regions
(2021-12-01)
Buranasiri, Prathan
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Plaipichit, Suwan
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Puttharugsa, Chokchai
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Wicharn, Surawut
In this work, spectral absorbance of hybrid nanowire-hyperbolic metamaterial was investigated numerically by using transfer-matrix method. The hybrid nanowire-hyperbolic metamaterial is consisted of two-dimensional periodically arranged arrays of subwavelength-sized hybrid nanowires (with circular cross-section) embedded in silicon dioxide host matrix. Each hybrid nanowire is made by core-shell structure used silicon as a core and gold as a shell. The hybrid nanowire-hyperbolic metamaterial is used as a top layer of a broadband absorber. The top layer is over on a planar silicon dioxide layer, which is backed by a nano-sized layer of gold as a perfect reflector for guaranteeing high absorbance. When electromagnetic waves in the range of 400–1600 nm wavelength are obliquely incident on the top hybrid nanowire-hyperbolic metamaterial surface, the absorption spectra of the designed absorber structure are analyzed for different incident angles, and radii of hybrid nanowire components or fill-factor of the hyperbolic metamaterial layer. The multiple absorption peaks, which are continuously generated from multiple longitudinal and transverse surface plasmon modes and are supported by the hybrid nanowires, are observed directly. The absorption feature can be also tuned by various operational conditions. The proposed structure is made by in-complex nano-fabricating techniques comparing with the another and it provides acceptable broadband absorptivity.
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Wide-Angle Dual-Band Absorber Based on Nanowire-Hyperbolic Medium
(2021-03-10)
Wicharn, Surawut
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Plaipichit, Suwan
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Buranasiri, Prathan
We proposed a dual-band absorber in the visible regime by using nanowire-hyperbolic medium, which is composed of an array of subwavelength-sized hybrid nanowires immersed in dielectric matrix, as a top layer, silicon dioxide as a middle layer, and gold as a bottom layer. Each nanowire is made by core-shell structure, which has silicon as a core and gold as a shell. We found that the dual-band absorption originated from impedance matching between incident medium impedance and input impedance of the proposed absorber at first-and second-order resonant modes. Furthermore, the absorbance can be controlled by adding or reducing filling factor of hyperbolic medium layer. In addition, the absorption performance of the absorber retains well in wide angles. This dual-band absorber is a good candidate for potential applications such as thermal radiation tailoring and sensitive detection.

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