Small Core Diameter Research Articles

Is Bigger Better? Comparison of 150 µm and 200 µm Thulium Fiber for In Situ Lower-Pole Lithotripsy.

Introduction: The thulium fiber laser (TFL) generates a focused beam, which can be transmitted to laser fibers with small core diameters and may facilitate in situ lower-pole lithotripsy. This study compares lithotripsy performance of the 150 and 200 µm TFL in a lower pole benchtop kidney model. Materials and Methods: Using a 3D model printed from an actual kidney, in situ laser lithotripsy was performed on 1 cm lower-pole BegoStones (calcium oxalate monohydrate consistency) using four different settings (all 20W) and two fiber sizes (150 and 200 µm). Procedure time, laser time, total pulse energy, and fiber stripping were compared between the two fibers using an ANOVA or independent t-test. Results: The 150 µm fiber at 0.2 J × 100 Hz had the shortest lasing and procedure time (17.3 and 18.5 minutes) and lowest total pulse energy (20.75 kJ) compared with other study arms (p < 0.001). Overall procedure time, lasing time, and total pulse energy were significantly different between the 8 settings (p < 0.001 for all). At higher frequency (100 and 200 Hz), lasing time was significantly faster compared with 20 and 50 Hz (19.9 vs 27.3 minutes; p < 0.001). Furthermore, the average total procedure time was shorter with 150 µm compared with 200 µm regardless of settings (23.2 vs 29.8 minutes; p < 0.001). Conclusion: The 150 µm fiber results in shorter procedure and lasing time at lower total energy levels during lower-pole in situ lithotripsy. Overall, the fastest setting was 0.2 J and 100 Hz with the 150 µm fiber. Smaller laser fibers can potentially allow more efficient in situ laser lithotripsy with better irrigation and visibility at higher deflection angles.

Non-invasive FBG-based contact lens for continuous intraocular pressure monitoring

The intraocular pressure (IOP), or pressure inside the eye, is one of the key indicator for glaucoma diagnosis and treatment. The present work shows the design and fabrication of a non-invasive Fiber Bragg Grating (FBG) based contact lens for continuous IOP monitoring. By employing wet etching to reduce the FBG diameter, FBG based contact lens sensitivity and mechanical flexibility are enhanced. The contact lens is made of an optical fiber with a small core diameter that has an inscribed FBG of length 3 mm and is etched for a length of 40 mm to facilitate coiling the eFBG during fabrication. The soft contact lens was fabricated using flexible thin film technology with a transparent and flexible etched Fiber Bragg Grating (eFBG) integrated within flexible polydimethylsiloxane (PDMS) for sensing corneal deformations brought about by IOP variations. Experimental studies on the bionic eyeball model show that the Bragg wavelength shift is highly linear (r2 = 0.9694), with a very good sensitivity of 49.243 pm/mmHg in the IOP pressure range of 0 to 50 mmHg. Due to its ease of fabricating, simplicity of design, and ability to continuously measure pressure with good repeatability and stability, the proposed sensor thus offers a potential solution for IOP monitoring.

Single-longitudinal-mode narrow linewidth broadband tunable Brillouin random laser including dispersion compensation fibers

We propose and demonstrate a single-longitudinal mode (SLM) narrow linewidth broadband tunable Brillouin random laser, including two segment dispersion compensated fibers (DCFs), in which enough narrowband Brillouin gain provided by a 2-km-length DCF to overcome the cavity loss, and Rayleigh backscattering (RBS) provided by a 1-km-length DCF form a mirrorless open cavity to continuously compress the laser linewidth. Compared to ordinary single mode fibers, DCF has an enhanced stimulated Brillouin scattering gain coefficient and RBS coefficient, which is attributed to its small core diameter structure, making the laser more compact and stable. Stronger random feedback effectively lowers the laser threshold, and enough Brillouin gain for multiple amplifications in random mode makes SLM operations more accessible. The proposed laser is with a threshold of ∼11 mW and an optical signal-to-noise ratio (OSNR) of ∼55.75 dB, the 3-dB linewidth and linewidth compression ratio of the output laser reaches ∼550 Hz and ∼236, respectively. By changing the wavelength of the pump laser, the laser wavelength can be continuously tuned in a broad wavelength range, which is only limited by tunable range of Brillouin pump laser. The laser wavelength fluctuation of 0.02 nm and the OSNR fluctuation of about 3 dB in a 30-minute measure period, indicating that the laser is with a good stability.

Novel Multi-State QDC-QDG FETs and Gate All Around (GAA) FETs for Integrated Logic and QD-NVRAMs

This paper presents experimental I-V characteristics of a QDC-QDG FET that exhibited 5-states and has the potential to introduce additional states (e.g. 8) by utilizing Ge QDSL mini-energy sub-bands. Mini-energy bands are formed in an asymmetric Si quantum dot channel (QDC) comprising of two silicon oxide cladded Si quantum dots (QDs), where the upper layer has a smaller core diameter and thicker upper oxide cladding serving as tunnel oxide. Quantum simulations are presented to show more states when additional two germanium oxide cladded Ge dots are added on top of Si QD layers in the gate region. This paper also proposes Gate all around (GAA) FETs, when integrated with nonvolatile random access memories (NVRAMs) that have the potential for wafer scale integration, similar to vertical NANDs. Novel Si and Ge Quantum-dot-based device configurations discussed in this paper open the pathway forward to implement hardware platform for emerging applications using low power consumption and smaller footprint.

Thermocapillary flow‐induced core release from double‐emulsion droplets in microchannels

AbstractThe use of double emulsions (DEs), which represent colloidal structures composed of droplets nested within droplets, can provide for unparallel droplet manipulation in droplet‐based microfluidic technology due to their unique core–shell structures. The controlled release of cores in DEs is of particular interest. However, this process remains poorly explored. In this work, the thermocapillary flow induced by a temperature gradient is used as a driving force to control the core release and the impacts of different linear temperature gradients, core diameters, shell diameter, and core/shell diameter ratios on the thermocapillary flow and core release characteristics of DE droplets consisting of a water‐in‐n‐hexadecane‐in‐water system within a cylindrical microchannel are investigated. Most of the core and shell diameter conditions considered result in a double‐core release process, where the inner droplet volume is partially ejected before the remaining core is rewrapped by the outer droplet, and the remaining inner droplet volume is ejected later during a second core release event. However, relatively small core diameters of 50 and 75 μm produce conditions where the full inner droplet volume is ejected during a single‐core release process. In addition, we provide empirical relationships for accurately determining the time at which core release initially occurs under given DE parameters as well as for precisely determining whether the applied conditions will lead to single‐ or double‐core release processes. Therefore, the results of this study provide insights enabling the development of accurate inner droplet release technologies under thermocapillary migration.

Broadband supercontinuum generation in cascaded tapered liquid core fiber

Most recent broad supercontinuum sources have used nonlinear fibers with small core diameters, resulting in low coupling efficiency, limiting power level launching into the fiber, and low spectral power density. In this work, we numerically investigate tapered liquid-core fibers for supercontinuum generation that have a potential for both high coupling efficiency (with a standard SMF-28 fiber) and high nonlinear effects. Carbon disulfide is selected to fill into the fibers because of its high nonlinear refractive index and high transparency from the visible to the mid-infrared range. We consider cascaded fibers including SMF-28 and the tapered liquid-core fibers for all-normal and anomalous dispersion supercontinuum generation pumped by C-band femtosecond lasers (1560 nm, 90 fs). In such a case, we obtain all-normal dispersion supercontinuum generation with flat-top, broad bandwidth (1.0–2.5μm) via an input peak power of 27 kW. By changing the core diameter of the tapered fiber, we also yield anomalous dispersion supercontinuum generation with broad spectral bandwidth (1.0–3.3μm). In addition, the use of the cascaded tapered fibers is possible to mitigate fiber damage (via thermal effects of a high-power laser on the selected liquids) and increase stability of output supercontinuum spectra. In this context, supercontinuum generation in the cascaded fibers by using a picosecond laser with high average power (≈ 800 mW) is considered towards applications requiring high spectral power density (e.g., multiphoton imaging techniques).

Microfluidic device-fabricated spiky nano-burflower shape gold nanomaterials facilitate large biomolecule delivery into cells using infrared light pulses.

Photothermal nanoparticle-sensitised photoporation is an emerging approach, which is considered an efficient tool for the intracellular delivery of biomolecules. Nevertheless, using this method to achieve high transfection efficiency generally compromises cell viability and uneven distribution of nanoparticles results in non-uniform delivery. Here, we show that high aspect ratio gold nano-burflowers, synthesised in a microfluidic device, facilitate highly efficient small to very-large cargo delivery uniformly using infrared light pulses without sacrificing cell viability. By precisely controlling the flow rates of shaping reagent and reducing agent, high-density (24 numbers) sharply branched spikes (∼80 nm tip-to-tip length) of higher aspect ratios (∼6.5) with a small core diameter (∼45 nm) were synthesised. As produced gold burflower-shape nanoparticles are biocompatible, colloidally stable (large surface zeta potential value), and uniform in morphology with a higher plasmonic peak (max. 890 nm). Theoretical analysis revealed that spikes on the nanoparticles generate a higher electromagnetic field enhancement upon interaction with light pulses. It induces plasmonic nanobubbles in the vicinity of the cells, followed by pore formation on the membrane leading to diverse biomolecular delivery into cells. Our platform has been successfully implemented for uniform delivery of small to very large biomolecules, including siRNA (20-24 bp), plasmid DNA expressing green fluorescent protein (6.2 kbp), Cas-9 plasmid (9.3 kbp), and β-galactosidase enzyme (465 kDa) into diverse mammalian cells with high transfection efficiency and cell viability. For very large biomolecules such as enzymes, the best results were achieved as ∼100% transfection efficiency and ∼100% cell viability in SiHa cells. Together, our findings demonstrate that the spiky gold nano-burflower shape nanoparticles manufactured in a microfluidic system exhibited excellent plasmonic behaviour and could serve as an effective tool in manipulating cell physiology.

Numerical analysis of the mechanical and electrical properties of CORC cables under torsional loading

The type II high-temperature superconducting (HTS) ReBCO tapes have been widely used in high-field magnets. Conductors on round core (CORC) cables can carry very high currents in background magnetic fields exceeding 20 T, making it one of the most important types of HTS cables. However, the cables of the magnets in the fusion reactor are subjected to large mechanical and electromagnetic loads that may twist the CORC cables. The intrinsic strain of the superconducting cable is constrained by the brittleness of the HTS tape, which, if exceeded, will cause irreversible damage by producing cracks in the ReBCO layer. A finite element (FE) model was developed to predict how the CORC cable will perform in torsional cases. A comparison of numerical simulations with experiments for a single- and double-layer CORC cable is first performed to validate the model's reliability. For single-layer CORC cables, our model reduces the error between FE results and experiments from 46.7% to 6.7%. Variations in the winding angle, tape width, Poisson's ratio of the CORC cable core material, and core radius were made as part of the parametric analysis. The critical torsion angle is analyzed from the perspective of critical current density reduction. The results show that maintaining a small tape gap (smaller winding angle (26−30°), smaller core diameter, and larger tape width) and a small Poisson ratio can improve the strain limit of the ReBCO layer. The reason for the plateau phenomenon in the normalized critical current density curve of the double-layer CORC cable is reinterpreted. It is also confirmed that multi-layer CORC cables still need to maintain a small tape gap. The FE model can guide optimizing a cable design for specific application conditions.

Surface plasmon resonance tunable gold nanostar synthesis in a symmetric flow-focusing droplet device

Gold nanomaterials are known for their unique optical properties due to their localized surface plasmon resonance (LSPR). Controllable gold nanomaterials synthesis to tune LSPR of specific application demands is of great interest in the scientific community and is technically challenging to achieve in a conventional batch reactor. In this work, we tailored LSPR tunable gold nanostars (Au NS) using a symmetric flow-focusing droplet device after optimizing the flow parameters in 2D simulations. Simulations were used to represent the fluid interface within the device microchannels and helped to study the droplet evolution and their quantification. As nanomaterials synthesis in a droplet device demands the production of homogenous droplets and control over their size and production rate, we optimized the flow parameters from the simulation. By incorporating curved, sinusoidal geometries and semi-spiral microchannels, the mixing of reagents inside the droplet was improved for synthesizing heavily branched Au NS. The best performance was achieved when the flow rate of the shaping reagent was twice that of other reagents. As-synthesized Au NS are non-toxic, uniform and possess a small core diameter, large tip-to-tip length, negative surface zeta potential and red-shifted LSPR. These features are highly favourable for photothermal and photodynamic applications. Thus, our microfluidic platform can produce uniform droplets that provide sufficient mixing of reagents for the application-specific LSPR tunable synthesis of gold nanostars.

Fiber cladding dual channel surface plasmon resonance sensor based on S-type fiber

Fiber cladding surface plasmon resonance (SPR) sensors have few structures, and a clad SPR sensor based on S-type fiber is proposed in this paper. This new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding. In this paper, the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment. Based on the conclusion that the smaller the core diameter is, the closer the working band of the SPR resonance is to long wavelengths, and that the geometric characteristics mean that a multimode fiber can receive the fiber cladding light from a small core diameter few-mode fiber, a dual channel SPR sensor with a double S-type fiber cascade was proposed. In the refractive index detection range of 1.333–1.385 refractive index units (RIU), the resonant working band of channel I is 627.66 nm–759.78 nm, with an average sensitivity of 2540.77 nm/RIU, and the resonant working band of channel II is 518.24 nm–658.2 nm, with an average sensitivity of 2691.54 nm/RIU. The processing method for the S-type fiber cladding SPR sensor is simple, effectively solving the problem of this type of SPR sensor structure and the difficult realization of a dual channel. The sensor is expected to be used in the fields of medical treatment and biological analysis.

A 6.4-kW peak power near-single-mode quasi-continuous wave fiber laser oscillator employing spindle-shaped ytterbium-doped fiber

High peak power quasi-continuous wave (QCW) fiber lasers with good beam quality are widely used in industry. But it’s difficult to balance the peak power and the good beam quality for common lasers. We proposed a novel QCW fiber laser oscillator, employing a 24 m long spindle-shaped ytterbium-doped fiber (YDF), which has a core/cladding diameter of 25/400–37.5/600–25/400 μm. The large core diameter section in the middle and tapered sections are 20 m long in total for suppressing the nonlinear effects in the laser cavity, and the small core diameter sections in two ends are 4 m to result in good beam quality. Finally, a near-single-mode QCW fiber laser oscillator with a beam quality of 1.38 (M2 factor) and peak power of 6.4 kW is achieved, accompanying with a high stimulated Raman scattering (SRS) suppression ratio of 20.3 dB. To the best of our knowledge, this is the first time to adopt a spindle-shaped YDF in a QCW fiber laser, and also the highest output power of near-single-mode QCW fiber lasers ever reported.

Simultaneous illumination and imaging based on a single multimode fiber.

Due to the small core diameter, a single-core multimode fiber (MMF) has been extensively investigated for endoscopic imaging. However, an extra light path is always utilized for illumination in MMF imaging system, which takes more space and is inapplicable in practical endoscopy imaging. In order to make the imaging system more practical and compact, we proposed a dual-function MMF imaging system, which can simultaneously transmit the illumination light and the images through the same imaging fiber. Meanwhile, a new deep learning-based encoder-decoder network with full-connected (FC) layers was designed for image reconstruction. We conducted an experiment of transmitting images via a 1.6 m long MMF to verify the effectiveness of the dual-function MMF imaging system. The experimental results show that the proposed network achieves the best reconstruction performance compared with the other four networks on different datasets. Besides, it is worth mentioning that the cropped speckle patterns can still be used to reconstruct the original images, which helps to reduce the computing complexity significantly. We also demonstrated the ability of cross-domain generalization of the proposed network. The proposed system shows the potential for more compact endoscopic imaging without external illumination.

Dispersion and nonlinearity properties of small solid-core photonic fibers with As2Se3 substrate

Characteristics of As2Se3 photonic crystal fibers (PCFs) with a solid-core and small-core diameter are numerically investigated in the long-wavelength range (from 2 to 10 μm). A full modal analysis and optical properties of designed photonic crystal fibers with lattice constant Λ and filling factor d/Λ are presented in terms of chromatic dispersion, effective refractive index, nonlinear coefficients, and confinement loss. The simulation results show that a high nonlinear coefficient of 4410.303 W–1·km–1 and a low confinement loss of 10−20 dB·km–1 can simultaneously be achieved in the proposed PCFs at a 4.5 μm wavelength. Chromatic dispersions are flat. The values of dispersion increase with increasing filling factor d/Λ and decrease with the increase in lattice constant Λ. In particular, some chromatic dispersion curves also cut the zero-dispersion line at two points. The flat dispersion feature, high nonlinearity, and small confinement loss of the proposed photonic crystal fiber structure make it suitable for supercontinuum.

Low Divergence Structured Beam In View Of Precise Long-Range Alignment

A new method of generation of a Structured Laser Beam (SLB) with non-diverging central core was proposed and is promising for creating long distance multipoint alignment systems. This beam is generated by a set-up consisting of two convex lenses in Kepler telescope arrangement. The first one is a high refractive index ball lens, second one is a standard lens. The beam, in cross-section consisting of light and dark concentric circles, propagates over a large distance. The central core of the SLB has a very small divergence which can be tuned. A divergence of 10 μrad was proven experimentally. In this experiment, the small initial beam core diameter of 10 μm, and its diameter of 1.5 mm at a distance of 150 m, show its ability for use as a multipoint fiducial reference line. This small beam divergence seemingly lies beyond the diffraction limit for laser beams.

Material constraint‐based laser performance estimation of Yb3+‐doped phosphate fibers

AbstractBased on the material properties of 47 Yb3+‐doped phosphate fibers with different sizes and lengths, a laser performance estimation model was established to estimate the laser wavelength just above the threshold (λth), the laser threshold (Pth), and the laser slope efficiency (η). This model was solved via a numerical computing method with an accuracy of 0.01. Under the material constraints of this model, λth, Pth, and η were investigated by sensitivity analysis and Monte Carlo numerical simulation. The results show that short fibers with a small core diameter may more easily produce a shorter λth. Additionally, for constant material properties, fibers with a longer λth may have a lower Pth and higher η than other fibers. Verifying the above conjecture, an output power of 8.7 W with 35% enhancement in slope efficiency was obtained from an optimized phosphate fiber for an optical path in which the output of the short‐wave laser was inhibited. This model can be extended to simulate the lasing wavelength of multi‐composition fibers, providing a theoretical basis for special laser bands, laser material preparation, and fiber structure design.

High-speed multimode fiber imaging system based on conditional generative adversarial network

The multimode fiber (MMF) has great potential to transmit high-resolution images with less invasive methods in endoscopy due to its large number of spatial modes and small core diameter. However, spatial modes crosstalk will inevitably occur in MMFs, which makes the received images become speckles. A conditional generative adversarial network (GAN) composed of a generator and a discriminator was utilized to reconstruct the received speckles. We conduct an MMF imaging experimental system of transmitting over 1 m MMF with a 50 µm core. Compared with the conventional method of U-net, this conditional GAN could reconstruct images with fewer training datasets to achieve the same performance and shows higher feature extraction capability.

Preparation of Polymer Optical Fiber and Application to Water Purification

The photocatalytic reaction uses light energy to advance various chemical reactions, so they are attracting attention as a clean process. The range of photocatalysis applications is wide, and it has been put into practical use and researched in many fields such as water splitting for energy production, self-cleaning, and environmental purification. We focused on the field of water purification using photocatalysts. Hydroxyl radicals generated by electrons excited on the photocatalyst by light irradiation have strong oxidation. It removes harmful compounds such as organic compounds and bacteria. When decomposing harmful substances using a photocatalyst in water purification, the surface of the material coated with the photocatalyst is irradiated with light.However, photocatalysis requires the introduction of light, which limits its use in dark places such as suspended water, water pipes, and water tanks. One way to address these issues is to provide the photocatalyst with light from the coating material itself. Optical fiber composites have been devised as one such method. Devices reported to date have consisted of silica fibers coated with a photocatalyst. However, silica fiber has limitations such as weak bending, small core diameter, and material cost. To overcome these shortcomings, we combined plastic optical fibers and photocatalysts. Plastic optical fiber（POF）was selected because it is more bendable than silica optical fiber, has a larger core diameter, is lower cost, and is easier to process.Next, we examined the light leakage method. In previous studies, removal of the fiber cladding by heat or physical damage was common. However, it is not a preferable method for increasing the number of manufacturing processes and for uniform light leakage. This time, during the fiber manufacturing process, an optical fiber that leaks light was added by adding a light scattering agent during core manufacturing.The light Leakage-type plastic optical fiber（POF）were made using previously reported methods. The preform was made by polymerizing methyl methacrylate (179 g, MMA) into a tubular shape with closed ends. (inner diameter / outer diameter 14.7 / 22.0 mm, length 600 mm).3.87 mg of titanium dioxide (TiO2) powder (P25), which is a material with a high refractive index, was added as a scattering agent when manufacturing the core. Then, the obtained preform was heat-drawn to produce L-POF having a diameter of 1000 μm.The photocatalyst layer was formed by three kinds of coating methods. In the dip coating method, the photocatalyst layer was formed by immersing the fiber in a suspension of TiO2 dispersed in ethanol. In the paste coating method, commercially available TiO2 paste Was applied to the fiber. In the two-layer coating method, an adhesive solvent (NRC-300A,) was dip coated, and then an adhesive solvent (NRC-300C) in which TiO2 was similarly dispersed was dip coated.The fabricated fiber was evaluated by near-field pattern measurement. This is to measure the light intensity at the fiber end face by observing the laser light incident from the end face of the optical fiber with a CCD camera installed at the other end face. The surface of each coated fiber was observed with a scanning electron microscope (SEM, S4800). The photocatalytic performance was evaluated by a methylene blue decomposition experiment.In this study, we succeeded in producing L-POF by adding a light scattering agent to the core of POF. In addition, a TiO2 photocatalyst layer was formed on the surface, enabling decomposition of organic substances in the dark. Light incident from the end face of L-POF leaks into the clad layer due to the scattering agent inside the core and excites the photocatalyst. Electron-hole carriers excited on the photocatalyst generate reactive oxygen species that decompose methylene blue. Since this method uses POF, which is inexpensive and easy to process, it can realize various photocatalytic reactions not only in the purification of contaminated water but also in dark places. By changing the incident light and coating the photocatalyst, devices suitable for various reactions can be made. From a practical point of view, by connecting a POF and photocatalytic L-POF, light could be transported to target areas for photocatalytic application with reduced light loss. Figure 1

Highly Sensitive Fiber Ring Laser Sensor for Curvature Using a Modal Interferometer

A curvature sensing Ytterbium-doped fiber ring, using a Thin Core Fiber Modal Interferometer (TCFMI) was experimentally demonstrated in this work. The TCFMI was implemented by fusion splicing a segment of a thin-core fiber, with a small core diameter, between two single-mode fiber sections. The proposed TCFMI functioned as a wavelength-selective filter in the fiber ring laser cavity. It was optimized to achieve a Side Mode Suppression Ratio (SMSR) of 35 dB; the laser emission produced a sensor resolution of 0.37 nm. The experimental results also showed a high curvature sensitivity close to −38.26 nm/ $\text{m}^{{-1}}$ from 0 $\text{m}^{{-1}}$ to 0.399 $\text{m}^{{-1}}$ curvature range. Here, the laser sensor exhibited a bandwidth of 16 nm in the 1072 nm to 1056 nm wavelength range. The fiber ring laser is a low-cost alternative for curvature sensing applications.

Mitigation of Polarization Effects in Single-mode Fiber Spectrographs

The use of single-mode fibers (SMFs) to illuminate radial velocity (RV) spectrographs shows promise to achieve extremely precise Doppler measurements. Due to their small core diameter, SMFs only propagate a single spatial mode which allows for diffraction-limited optical performance while simultaneously eliminating fiber modal noise. The single spatial mode however consists of two orthogonal polarization modes. In circular core fiber with a non-isotropic refractive index profile or asymmetries in the cross-sectional geometry, the two polarization modes propagate with different relative speeds inducing birefringence. Conditions at a telescope observatory will subject the fiber to mechanical (bending and twisting) and thermal stresses, inducing birefringence that varies in time. The interaction of variable birefringence combined with with polarization sensitive optics, such as diffraction gratings, results in an intensity modulation that causes unwanted Doppler shifts via “polarization noise.” In this paper, we characterize variable fiber birefringence both in the laboratory and at the Large Binocular Telescope using a Stokes parameters. We then combine the measured Stokes vector through a numerical model of a SMF spectrograph to understand the impact of variable polarization on RV precision. We find that polarization noise is a tens of cm s−1 to several m s−1 effect, which is exacerbated by the degree of polarization of the light source and the polarization response of the spectrograph optics. Finally we show experimentally mitigating the RV offset using polarization averaging methods and in-line fiber depolarizers and can reduce a several m s−1 polarization noise to σ ≤10 cm s−1.

Correlation of concrete by using small core diameter

One of the causes of limited sampling on concrete structures is that there is reinforcement in the concrete structure so that when using a large diameter drill core, can damage the concrete structure. Therefore, a study of small diameter concrete was conducted to predict the compressive strength of cylindrical concrete. Test specimens in the form of concrete cylinders with dimensions 10 cm x 20 cm, two concrete plates with dimension 45cm x 45cm x 13cm, and four concrete beams with dimensions 70 cm x 30 cm x 15 cm by taking concrete using a drill core diameter of 2″ and 1″. Two concrete slabs and two concrete beams with concrete strength (f′c) 20 MPa (MSA 20mm and 10mm) while two concrete slabs and two concrete beams with concrete strength (f′c) 30 MPA (MSA 20mm and 10mm). Types of tests carried out include testing the compressive strength of concrete, core concrete normality test, modulus of elasticity and compressive strength of the core concrete. From test results, can be concluded that the compressive strength of core concrete with sample in the direction of casting for a diameter of 2 inches and concrete strength of 20 MPa (MSA 20 mm and 10 mm) meets the requirements and can be recommended with number samples of 25, whereas for diameter 1″ the number of samples must be added.