KEYWORDS: Deep learning, Digital holography, Holography, 3D image reconstruction, Education and training, Ocean optics, Holograms, Data modeling, Image classification, Performance modeling
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.
The electrochemical properties of NiCo2O4 for using as electrode materials for the potential applications have been investigated by electrochemical measurement which composed of cyclic voltammetry (CV) and galvanostatic chargedischarge (GCD). These processes are generating the ion exchange between the electrode and electrolyte, wherein induce the surface change of the interface. Especially, since in the cycle ability measurement using the potentiostat needed to repeat the cycle into the electrode for many times, the effective of the electrode is reduced. In this research, digital holographic technique was used to investigate the different properties of interface of the NiCo2O4 electrode while operating under the various electrochemical techniques. In our DH recording, the surface change of the electrode was expose at the difference potential scan rate at 1, 5, 10, 50, 100 and 200 mV/s of CV, and the difference current densities at 1, 2, 3, 5, 10 and 20 A/g of GCD and vary times of cycle ability test every 50 cycle times to 1000 cycles. In the end the reconstructed DH images of the electrode have been used to analyze the results from electrochemical measurement.
In this study, we numerically investigated the absorption properties in one-dimensional photonic hypercrystal (PHC), which was consisted of a periodically alternating layers of hyperbolic metamaterial and dielectric material. The first layer of the unit cell of the PHC is a hyperbolic metamaterial (HMM), which made of the two-dimensional square lattice arrangement of gold (Au) nanowire embedded in indium tin oxide (ITO) host and the second layer is the same dielectric material used in metamaterial system. First, the nanowire array hyperbolic metamaterial was designed for providing high extinction coefficient in visible light to near infrared region by optimizing the radius of each Au nanowires. Then, a transfer-matrix method (TMM) was used as the numerical tool for calculating the absorption spectrum of the PHC for both TE- and TM-polarization. The numerical results showed that the PHC structure provides the widest absorption spectrum in the range of 500 to 1,000 nm for TE-polarized wave incidence. The bandwidth of interesting absorption spectrum is increased when increasing the layer thickness of the composed dielectric material. The level of absorbance of PHC is enhanced by increasing the number of periods. Conversely, the absorbance of PHC structure is decreased with the greater incident angle. Finally, the fill factor of nanowire hyperbolic metamaterial will make the shifting of absorption spectrum into long-wavelength region when it is decreased. Meanwhile, the absorption of TM-polarized wave in PHC structure is too low when comparing with TE-wave case. Due to the influence of the above parameters on the absorption spectrum for TE-polarized wave, so the PHC may be used as the TE broadband absorber for energy harvesting application.
The purpose of the study was to investigate of photorefractive Bragg gratings within iron-doped lithium niobate crystals with the size of seven cubic millimeters. Polarized helium-neon laser beams with a wavelength of 633 nm have been separated into two beams and then incident on the crystal with different angles. Both beams were used for writing the grating in the crystal with the incident angle (2θ). and the angle between both beams has been founded the highest efficiency of diffraction beams. Then the transport of intensity method was used to explore the grating characteristics by using the opposite polarization of the writing helium-neon laser beam. Images in focus and defocus before and after the focal plane was recorded on a Canon digital camera. Then, these images were used to process by computer programing based on the principle of transport of intensity equation. By using this technique, the grating characteristics in lithium niobate crystals would be investigated.
In this work, the digital holography technique was used to examine different types of colors on the painting. Quantitative phase imaging by in-line digital holography is used to get the phase profile of image bearing beam from total internal reflection, which is modulated by the paintings of different kinds of color on the surface of internal reflection. The experimental results were shown that the reconstructed images of different kinds of colors which were painted on both black and white fine face papers could be observed more details than those on rough face papers. The reconstructed images have been shown the details of homogeneity of different kinds of colors. By improving the technique, this approach would be used for the examination of particular piece of paintings in the future.
Multilayered hyperbolic metamaterials (MHM) is proposed to create phase matching of fundamental-frequency (FF) and third-harmonic (TH) field components with a unique dispersion provided by the engineered MHM structure for third-harmonic generation in ultra-short pulse regime. In this work, we analytically study the ensuing possibilities and demonstrate that a birefringent phase-matching can be alternatively achieved with a wide range of involved material parameters and optimal engineering of MHM structure. When the phase-matched conditions is satisfied by birefringent phase-matching method, the growth rate of the TH intensity generating as a function of the nonlinear-optical interaction length to be obviously increased. This method opens new ways of improving the conversion efficiency of frequency tripling regardless of the coherence length in the bulk of a nonlinear material.
In this research, two-wave coupling in photorefractive lithium niobate crystal has been used to do imaging enhancement of digital holography (DH) system. The image bearing beam of in-line DH system has been incident and interfered with a reference beam that was emerged from the same laser on a LiNbO3 crystal. With certain angles between both beams, the energy of the reference beam was transferred to the image bearing beam then resulted the enhancement of the reconstructed image of the DH system. By using the suitable intensity of laser beam with a right PR crystal, the image from an in-line DH imaging system would be improved.
In this paper we propose a modern technique to evaluate the shape changes of solder paste by using double-view in-line digital holography. We observed the transformation of three different kinds of solder paste composition: pure solder paste, solder paste mixed with 0.02%, 0.05%, 0.10% graphene (GPN) and 0.02%, 0.05%, 0.10% graphene oxide (GPNO), respectively. The shape of the solder pastes was investigated at different melt temperatures (i.e. 200°C, 250°C, and 300°C) for 30 seconds using a collimated beam propagating through the solder paste, then being double reflected on a mirror and second incident on another sides of the solder paste. The double images bearing beams were recorded with a CCD sensor simultaneously. The single recorded digital hologram from double view technique was reconstructed using digital holography. The results show that the double-view technique provides reliably data. Moreover, it would be developed for observing more than two images by single holography writing in the future.
In this paper, we discuss the digital holography (DH) experiment in our optical and communication laboratory course for undergraduate students at Physics department, KMITL. The purposes of DH experiment are presenting our students the meaning and advantage of DH and its applications. The Gabor configurations of in-line DH has been set up for recording a number of samples, which were placed on different distances, simultaneously. Then, the images of all objects have been numerical reconstructed by using computer. The students have been learned that all of reconstructed images have been got from only one time recording, while using the conventional recording technique, sharp images of different objects have been gotten from different recording time. The students also have been learned how to use DH technique for investigation some different kinds of samples on their own of interested such as a human hair or a fingerprint. In our future work, our DH system will be developed to be a portable apparatus for easily showing to children in different areas.
In this paper, the novel technique for investigating the quality of glass bottle by using digital in-line holography (DIH)
has been proposed. In our experimental setup, the collimated beam of short coherent laser diode with wave length of 635
nm incident on a glass bottle. Then, the image bearing reflected beam consisted of quality profile of the glass bottle has
been recorded on a CMOS camera. By using the experimental results and numerically reconstructed images, the defects
inside the glass bottle can be detected and the curvature radius of the bottle has been found. Our technique may be used
for glass bottle inspection in the glass bottle making industry.
Total internal reflection (TIR) is normally important in an optical fingerprint scanner. The moisture effect in a fingerprint scanner based on TIR has been explored by using digital in-line holography (DIH). First, the reflection and the transmission technique set up for DIH have been explored by using a positive resolution test target with a line width of 200 μm. From experimental results, the reconstructed image of the reflected DIH is perfect as the image of the transmitted DIH. Due to the advantage for opaque object imaging of the reflected DIH, reflected DIH based on TIR has been selected to investigate the moisture effect of the fingerprint. Fingerprints with moistures of 39%, 54%, 69%, and a soaked finger have been observed. A laser diode of 635 nm and a complementary metal oxide semiconductor camera were used in all of the experimental setups in this research. The reconstructed image of the fingerprint gives a sharper image than the directed recorded image. The fingerprint with higher moisture provided a darker fingerprint image, while the optimum amount of moisture that gives the most complete finger pattern is 54%.
In this research, the low cost optical tweezers systems using X-Y stage has been developed by using 5-phase stepping motor. By using sequential double coil driving, we can obtain the driving torque larger than using the single coil driving. The moving scale is fine resolution at 0.2 micrometer. The overall systems based on microcontroller PIC18F458 and joystick controller with LabView® graphical user interface (GUI). The mechanical damping has been included in the system for decreasing the vibrational noise. By using this method, our optical tweezers system is cheaper than the other commercial system that has been used the piezoelectric driving, and still has the same efficiency.
In this paper, optical phase conjugate beam with the using of different resonator configurations has been investigate. Two types of SPPC resonators were selected to use, the first one is linear resonators formed by crystal surface and the other one is linear resonators formed by single mirror and a photorefractive crystal. In our experiment, cerium doped barium titanate crystal (BaTiO3 : Ce) and He-Ne laser with wavelength of 632.8 nm have been used. From the results of both cases, the angle of the incident beams is optimum at 37.95° respect to the normal line of the surface that parallel to the c-axis of the crystal. The generating time of OPC beam are 150 seconds and 330 seconds for the first and second type resonators, respectively. The reflection ratios are equal to 8.75% and 5% for the first and second type resonators, respectively (the first type resonators could provide better reflection ratio).
In this paper, we have proposed the novel prototype of the portable fingerprint scanner. Using this method, the low coherence digital holography technique has been used to verify fingerprints. In our experiment, the Michelson’s interferometer has been setup first for determining the coherence length of a laser diode with wave length of 635 nm. In our model, the light transmission and reflection properties of the glass slide have been applied. Then, the glass slide has been used as a beam splitter for separating the light to two beams, which are the reference beam and fingerprint image bearing beam. The results show fingerprint pattern, which are reconstructed with numerical method.
Higher-order anisotropic self-diffraction up to third orders have been observed in Cerium doped barium titanate by using
red beam at 633 nm from He-Ne laser. In our experiment, the third orders and second orders have been observed
simultaneously for the first time from our knowledge. From our observation, the phase conjugate beam has not been
generated before and after the appearance of higher orders as observing when the green beam from the Argon-ion laser at
514.5 nm has been used. The diffraction efficiency and the decay rate of the grating have been measured as well in the
red light case.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.