Solution-Induced Degradation of the Silicon Nanobelt Field-Effect Transistor Biosensors.

Field-effect transistor (FET)-based biosensors are powerful analytical tools for detecting trace-specific biomolecules in diverse sample matrices, especially in the realms of pandemics and infectious diseases. The primary concern in applying these biosensors is their stability, a factor directly impacting the accuracy and reliability of sensing over extended durations. The risk of biosensor degradation is substantial, potentially jeopardizing the sensitivity and selectivity and leading to inaccurate readings, including the possibility of false positives or negatives. This paper delves into the documented degradation of silicon nanobelt FET (NBFET) biosensors induced by buffer solutions. The results highlight a positive correlation between immersion time and the threshold voltage of NBFET devices. Secondary ion mass spectrometry analysis demonstrates a gradual increase in sodium and potassium ion concentrations within the silicon as immersion days progress. This outcome is ascribed to the nanobelt's exposure to the buffer solution during the biosensing period, enabling ion penetration from the buffer into the silicon. This study emphasizes the critical need to address buffer-solution-induced degradation to ensure the long-term stability and performance of FET-based biosensors in practical applications.

Reconfigurable electro-optical logic gates using a 2-layer multilayer perceptron.

In this work, we aim to use the optical amplifiers, directional couplers and phase modulators to build the electro-optical gates. Thanks to the 2-layer-multilayer-perceptron structure, the inversion of matrix is performed to obtain the coupling ratio of the directional couplers and the phase delay of the phase modulators. The electro-optical OR, AND, XOR, NAND, NOR and XNOR gates are demonstrated. Moreover, we not only study the results under the ideal condition of device, but also discuss the imperfect situation with 1% error of fabrication or operation to study the tolerance of this system. Through our simulation results, the visibility of the gate output can be higher than 0.83. The gates can be fabricated in a silicon-based chip to develop the integrated optics computing system.

Application of the deep learning for the prediction of rainfall in Southern Taiwan.

Precipitation is useful information for assessing vital water resources, agriculture, ecosystems and hydrology. Data-driven model predictions using deep learning algorithms are promising for these purposes. Echo state network (ESN) and Deep Echo state network (DeepESN), referred to as Reservoir Computing (RC), are effective and speedy algorithms to process a large amount of data. In this study, we used the ESN and the DeepESN algorithms to analyze the meteorological hourly data from 2002 to 2014 at the Tainan Observatory in the southern Taiwan. The results show that the correlation coefficient by using the DeepESN was better than that by using the ESN and commercial neuronal network algorithms (Back-propagation network (BPN) and support vector regression (SVR), MATLAB, The MathWorks co.), and the accuracy of predicted rainfall by using the DeepESN can be significantly improved compared with those by using ESN, the BPN and the SVR. In sum, the DeepESN is a trustworthy and good method to predict rainfall; it could be applied to global climate forecasts which need high-volume data processing.

Optimization of Pulley-Type Ring Resonator with Waveguide Offset.

In this work, we dealt with the optimization of the pulley-type ring resonator using the offset of the straight input and output waveguide at the junction with the curved waveguide. We adopted the finite-difference time-domain method to simulate the structure. It was found that the coupling loss could be significantly reduced and the critical coupling could be precisely tuned. This results in the possibility of the Q-factor being higher than that of the structure without waveguide offset. In this study, the Q-factor of the ring resonator is increased from 9180 to 11,302. The corresponding enhancement is 23.1%.

Miniature Surface Plasmon Polariton Amplitude Modulator by Beat Frequency and Polarization Control.

The miniaturization of modulators keeps pace for the compact devices in optical applications. Here, we present a miniature surface plasmon polariton amplitude modulator (SPPAM) by directing and interfering surface plasmon polaritons on a nanofabricated chip. Our results show that this SPPAM enables two kinds of modulations. The first kind of modulation is controlled by encoding angular-frequency difference from a Zeeman laser, with a beat frequency of 1.66 MHz; the second of modulation is validated by periodically varying the polarization states from a polarization generator, with rotation frequencies of 0.5-10 k Hz. In addition, the normalized extinction ratio of our plasmonic structure reaches 100. Such miniaturized beat-frequency and polarization-controlled amplitude modulators open an avenue for the exploration of ultrasensitive nanosensors, nanocircuits, and other integrated nanophotonic devices.

Singular observation of the polarization-conversion effect for a gammadion-shaped metasurface.

In this article, the polarization-conversion effects of a gammadion-shaped metasurface in transmission and reflection modes are discussed. In our experiment, the polarization-conversion effect of a gammadion-shaped metasurface is investigated because of the contribution of the phase and amplitude anisotropies. According to our experimental and simulated results, the polarization property of the first-order transmitted diffraction is dominated by linear anisotropy and has weak depolarization; the first-order reflected diffraction exhibits both linear and circular anisotropies and has stronger depolarization than the transmission mode. These results are different from previously published research. The Mueller matrix ellipsometer and polar decomposition method will aid in the investigation of the polarization properties of other nanostructures.

Low power consumption and high-contrast light scattering based on polymer-dispersed liquid crystals doped with silver-coated polystyrene microspheres.

Polymer-dispersed liquid crystals (PDLCs) have attracted considerable attention for optical device applications in recent years. However, the high operating voltage of PDLCs limits their applications. This study reports a simple approach used for the first time to decrease the operating voltage of PDLCs by means of doping 3 µm-diameter silver-coated polystyrene microspheres (Ag-coated PSMSs) into PDLCs. Ag-coated PSMSs construct an induced electric field between each other when an external electric field is applied. This induced electric field can enhance the effective electric field so the operating voltage can be actively reduced from 77 V to 40 V. Such PDLCs also possess a high contrast ratio of >50 and a high on-state transmittance of ~73%. Therefore, PDLCs doped with Ag-coated PSMSs maintain a high contrast ratio and improve their electro-optical properties.

High Q-factor microring resonator wrapped by the curved waveguide.

In this work, we study the performances of ring resonators of different type by analyzing the bending loss and the condition of the critical coupling. We propose that the bending loss of microring can be reduced by wrapping a concentrically curved waveguide. The difference of propagation constant between two concentrically curved waveguides can be tuned by adjusting the bus waveguide width to optimize the critical coupling. Furthermore, we propose to enlarge the difference of the propagation constant between two concentrically curved waveguides to maintain the circulating light in the ring to obtain higher quality factor. In this study, the highest quality factor that we measured is 7 × 10(5).

Genetic algorithms optimization of photonic crystal fibers for half diffraction angle reduction of output beam.

In this work, we optimize the structure of the photonic crystal fibers by using genetic algorithms to provide strong light confinement in fiber and small half diffraction angle of output beam. Furthermore, this article shows the potentials of this study, such as optimizing three purposes at the same time and the arbitrary structure design is achieved. We report two optimized results obtained by different optimization conditions. The results show that the half diffraction angle of the output beam of the photonic crystal fibers can be reduced.

Design of a full-dynamic-range balanced detection heterodyne gyroscope with common-path configuration.

In this article, we propose an optical heterodyne common-path gyroscope which has common-path configuration and full-dynamic range. Different from traditional non-common-path optical heterodyne technique such as Mach-Zehnder or Michelson interferometers, we use a two-frequency laser light source (TFLS) which can generate two orthogonally polarized light with a beat frequency has a common-path configuration. By use of phase measurement, this optical heterodyne gyroscope not only has the capability to overcome the drawback of the traditional interferometric fiber optic gyro: lack for full-dynamic range, but also eliminate the total polarization rotation caused by SMFs. Moreover, we also demonstrate the potential of miniaturizing this gyroscope as a chip device. Theoretically, if we assume that the wavelength of the laser light is 1550nm, the SMFs are 250m in length, and the radius of the fiber ring is 3.5cm, the bias stability is 0.872 deg/hr.

Sensitive Faraday rotation measurement with auto-balanced photodetection.

A magneto-optic polarimetry based on auto-balanced photodetection is investigated. In this experiment, a commercial auto-balanced photoreceiver is adopted to measure the Faraday rotation of air. With a proper setup to utilize its noise cancellation capability, the measurement can be flexible and sensitive. The angular sensitivity is 2.99×10(-8) rad Hz(-1/2), which is about 2.7 times the shot noise limit. The measured Verdet constant of air is +1.39×10(-9) rad G(-1) cm(-1) at 634.8 nm. Significantly we applied a small AC current to induce the magnetic field, so there was no heating in the coil. In addition, a double current modulation scheme was used to demonstrate that there was no zero drift and amplifier instability in the measurement. The possibility of improvement of the angular sensitivity and the potential applications are also discussed.

Kinetics of glucose mutarotation assessed by an equal-amplitude paired polarized heterodyne polarimeter.

A dual-frequency equal-amplitude paired polarization heterodyne polarimeter (DEPHP) was set up in order to precisely measure the mutarotation rate constants of D-glucose in tridistilled water. The DEPHP is based on a balanced detector detection scheme for measurement of the optical rotation angle of D-glucose/water solution during the conversion process between alpha-D-glucose and beta-D-glucose while in a nonequilibrium state. The DEPHP can perform shot-noise-limited detection, so that the total optical rotation angle together with the mutarotation rate constants of alpha-D-glucose and beta-D-glucose conversion can be measured with high sensitivity. In this experiment, the sensitivity of the optical rotation angle measurement was 8.3 x 10(-5) deg/cm, while the total (k), forward (k(1)) and reverse (k(2)) mutarotation rate constants of D-glucose were found to be k = 7.67 x 10(-5) s(-1), k(1) = 2.76 x 10(-5) s(-1), and k(2) = 4.91 x 10(-5) s(-1), respectively, in tridistilled water. Moreover, using the DEPHP, we can measure the specific rotation angles of alpha-D-glucose and beta-D-glucose in water at 632.8 nm. They were 105 degrees and 12 degrees, respectively. Finally, the detection sensitivity of the DEPHP system is also discussed.

Paired circularly polarized heterodyne ellipsometer.

We develop a paired circularly polarized heterodyne ellipsometer (PCPHE), in which a heterodyne interferometer based on a two-frequency circularly polarized laser beam is set up. It belongs to an amplitude-sensitive ellipsometer that is able to provide not only a wider dynamic range of polarization modulation frequency but also a higher detection sensitivity than that of a conventional photometric ellipsometer. A real-time and precise measurement of ellipsometric parameters, which demonstrated an accuracy of less than 1 nm on thickness measurement of SiO(2) thin film deposited on silicon substrate, can be applied with the PCPHE.

Dual-frequency heterodyne ellipsometer for characterizing generalized elliptically birefringent media.

This research proposed a dual-frequency heterodyne ellipsometer (DHE) in which a dual-frequency collinearly polarized laser beam with equal amplitude and zero phase difference between p- and s-polarizations is setup. It is based on the polarizer-sample-analyzer, PSA configuration of the conventional ellipsometer. DHE enables to characterize a generalized elliptical phase retarder by treating it as the combination of a linear phase retarder and a polarization rotator. The method for measuring elliptical birefringence of an elliptical phase retarder based on the equivalence theorem of an unitary optical system was derived and the experimental verification by use of DHE was demonstrated too. The experimental results show the capability of DHE on characterization of a generalized phase retardation plate accurately.

High speed interferometric ellipsometer.

A novel high speed interferometric ellipsometer (HSIE) is proposed and demonstrated. It is based on a novel differential-phase decoder which is able to convert the phase modulation into amplitude modulation in a polarized heterodyne interferometer. Not only high detection sensitivity but also fast response ability on ellipsometric parameters (EP) measurements based on amplitude-sensitive method is constructed whereas different amplitudes with respect to P and S polarized heterodyne signals in this phase to amplitude modulation conversion is discussed. The ability of HSIE was verified by testing a quarter wave plate while a real time differential-phase detection of a liquid crystal device versus applied voltage by using HSIE was demonstrated too. These results confirm that HSIE is able to characterize the optical property of specimen in terms of EP at high speed and high detection sensitivity experimentally.

Degrees of polarization and coherence of paired linear polarized laser beam by scattering glass plates measured using optical coherent ellipsometer.

An accurate optical coherent ellipsometer (OCE) is proposed and setup in which a two-frequency paired linear polarized laser beam is integrated with a common-path heterodyne interferometer. This OCE is able to precisely measure the optical properties of scattering specimen by measuring ellipsometric parameters (Psi, Delta). In the mean time the degree of polarization P, and degree of coherence Chi of incident two-frequency linear polarized laser beam are measured too. In the experiment, both smooth and ground BK7 glass plates were tested in which the optical parameters (Psi, Delta, P, Chi ) were obtained precisely. Comparing with conventional ellipsometers, OCE can characterize scattering specimen precisely and excludes the scattering effect.

Polarized photon-pairs heterodyne polarimetry for ultrasensitive optical activity detection of a chiral medium.

A polarized photon-pairs heterodyne polarimetry is proposed in order to measure in an ultrasensitive manner the circular birefringence of a chiral medium via optical rotation detection. A balanced detector is integrated into this polarimeter. Thus, shot-noise-limited detection by this polarimeter can be achieved. Experimentally, the detection sensitivity for the circular birefringence of a glucose-water solution up to partial differential |n(r) - n(l)| = 2 x 10(-11) at 10 mg/dL is verified. To our knowledge, this is the highest sensitivity ever measured of a chiral liquid solution based on single traveling sample cell geometry. Finally, when compared to a fiber loop ring-resonator in the frequency domain for a chiral liquid, this polarimeter shows an order of 10(4) enhancement on the sensitivity of natural optical activity measurement.