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With the rapid development of mobile consumer electronics, Internet of Things, 5G, artificial intelligence, new energy vehicles and other technologies, the demand for high integration, high performance, fast heat dissipation and miniaturization of electronic packaging is becoming more and more urgent. In this paper, based on the traditional embedded silicon fan-out (eSiFO) package with a package size of less than 5mm*5mm, we have developed a super-large eSiFO packaging technology, in which the package size is up to 30mm*40mm, the embedded chip size is up to 14mm*14mm, and the number of I/Os is as high as 1808. After completing the successful development of critical process such as cavity etching, die attaching, and vacuum lamination, the super-size eSiFO package we manufactured has an electrical yield rate of 96%, and has passed the electrical test in uHast- B 264 hours and TC-B 1000 cycles. Regarding the key technical problems in the super-size eSiFO package, a systematic study was launched and some practical optimization suggestions were provided.

Dirac nodal-line semimetals with the linear bands crossing along a line or loop, represent a new topological state of matter. Here, by carrying out magnetotransport measurements and performing first-principle calculations, we demonstrate that such a state has been realized in high-quality single crystals of SrAs3. We obtain the nontrivial pi Berry phase by analysing the Shubnikov-de Haas quantum oscillations. We also observe a robust negative longitudinal magnetoresistance induced by the chiral anomaly. Accompanying first-principles calculations identify that a single hole pocket enclosing the loop nodes is responsible for these observations., Comment: Version as published in Science Bulletin

In this work, we have studied the oxidation process of the bismuth doped graphene in the ambient air. Complete oxidation of the bismuth clusters and that of the graphene are firmly confirmed. The influence of oxygen on the graphene is characterized by means of Hall measurement and SdH oscillation. All transport measurements demonstrate a hole-type doping behavior. Our work also demonstrates that the short-range scattering mechanism is enhanced in doped graphene due to accumulated O-species adsorbates after being exposed in the atmosphere for 40 days and is suppressed after annealing. This investigation may open a new perspective for fabricating the graphene metal oxide devices.

We fabricated nanodevices from Mo

We report the study of a triaxial vector magnetoresistance (MR) in nonmagnetic (Bi

We report the study of a tri-axial vector magnetoresistance (MR) in nonmagnetic (Bi1-xInx)2Se3 nanodevices at the composition of x = 0.08. We show a dumbbell-shaped in-plane negative MR up to room temperature as well as a large out-of-plane positive MR. MR at three directions is about in a -3%: -1%: 225% ratio at 2 K. Through both the thickness and composition-dependent magnetotransport measurements, we show that the in-plane negative MR is due to the topological phase transition enhanced intersurface coupling near the topological critical point. Our devices suggest the great potential for room-temperature spintronic applications, for example, vector magnetic sensors., Comment: 23 pages, 12 figures

The Laguerre-Gaussian (LG) modes constitute a complete basis set for representing the transverse structure of a {paraxial} photon field in free space. Earlier workers have shown how to construct a device for sorting a photon according to its azimuthal LG mode index, which describes the orbital angular momentum (OAM) carried by the field. In this paper we propose and demonstrate a mode sorter based on the fractional Fourier transform (FRFT) to efficiently decompose the optical field according to its radial profile. We experimentally characterize the performance of our implementation by separating individual radial modes as well as superposition states. The reported scheme can, in principle, achieve unit efficiency and thus can be suitable for applications that involve quantum states of light. This approach can be readily combined with existing OAM mode sorters to provide a complete characterization of the transverse profile of the optical field.

Here we introduce lattice defects in WTe2 by Ga+ implantation (GI), and study the effects of defects on the transport properties and electronic structures of the samples. Theoretical calculation shows that Te Frenkel defects is the dominant defect type, and Raman characterization results agree with this. Electrical transport measurements show that, after GI, significant changes are observed in magnetoresistance and Hall resistance. The classical two-band model analysis shows that both electron and hole concentration are significantly reduced. According to the calculated results, ion implantation leads to significant changes in the band structure and the Fermi surface of the WTe2. Our results indicate that defect engineering is an effective route of controlling the electronic properties of WTe2 devices.

The family of materials defined as ZrSiX (X = S, Se, Te) has been established as Dirac node-line semimetals, and subsequent study is urgent to exploit the promising applications of unusual magnetoresistance (MR) properties. Herein, we systematically investigated the anisotropic MR in the newly-discovered Dirac node-line material ZrSiSe. By applying a magnetic field of 3 T by a vector field, three-dimensional (3D) MR shows the strong anisotropy. The MR ratio of maximum and minimum directions reaches 7 at 3 T and keeps increasing at the higher magnetic field. The anisotropic MR forms a butterfly-shaped curve, indicating the quasi-2D electronic structures. This is further confirmed by the angular dependent Shubnikov-de Haas oscillations. The first-principles calculations establish the quasi-2D tubular-shaped Fermi surface near the X point in the Brillouin zone. Our finding sheds light on the 3D mapping of MR and the potential applications in magnetic sensors based on ZrSiSe.

Recently, the picture of type-II energy dispersion with broken Lorentz invariance has been adapted from Weyl to Dirac fermions. It is demonstrated in PdTe${}_{2}$ in this paper by extensive evidence from electrical transport, de Haas--van Alphen oscillations, first-principles calculations, and angle-resolved photoemission spectroscopy. The type-II Dirac cone looks like a pinnacle in momentum space. It may be cut by the Fermi level with the result of a pair of Dirac pockets (of $p$/$n$ type), whose sizes change dramatically with the Fermi level. The nontrivial Berry phase of the hole pocket is also displayed. This also means a nonvanishing density of states in the whole Dirac cones, which makes PdTe${}_{2}$ an improved platform for possible topological superconductors and Majorana fermions

We present a theoretical model to sufficiently investigate the optical rotational Doppler effect based on modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the difference of mode index between input and output orbital angular momentum (OAM) light, and linear to the rotating speed of spinning object as well. An experiment is carried out to verify the theoretical model. We explicitly suggest that the spatial spiral phase distribution of spinning object determines the frequency content. The theoretical model makes us better understand the physical processes of rotational Doppler effect, and thus has many related application fields, such as detection of rotating bodies, imaging of surface and measurement of OAM light., arXiv admin note: substantial text overlap with arXiv:1507.04102

The transverse structure of light is recognized as a resource that can be used to encode information onto photons and has been shown to be useful to enhance communication capacity as well as resolve point sources in superresolution imaging. The Laguerre–Gaussian (LG) modes form a complete and orthonormal basis set and are described by a radial index p and an orbital angular momentum (OAM) index ℓ. Earlier works have shown how to build a sorter for the radial index p or/and the OAM index ℓ of LG modes, but a scalable and dedicated LG mode sorter which simultaneous determinate p and ℓ is immature. Here we propose and experimentally demonstrate a scheme to accomplish complete LG mode sorting, which consists of a novel, robust radial mode sorter that can be used to couple radial modes to polarizations, an ℓ-dependent phase shifter and an OAM mode sorter. Our scheme is in principle efficient, scalable, and crosstalk-free, and therefore has potential for applications in optical communications, quantum information technology, superresolution imaging, and fiber optics.

We fabricated nanodevices from MoxW1−xTe2 (x = 0, 0.07, 0.35), and conducted a systematic comparative study of their electrical transport. Magnetoresistance measurements show that Mo doping can significantly suppress mobility and magnetoresistance. The results for the analysis of the two band model show that doping with Mo does not break the carrier balance. Through analysis of Shubnikov–de Haas oscillations, we found that Mo doping also has a strong suppressive effect on the quantum oscillation of the sample, and the higher the ratio of Mo, the fewer pockets were observed in our experiments. Furthermore, the effective mass of electron and hole increases gradually with increasing Mo ratio, while the corresponding quantum mobility decreases rapidly.

The simple and efficient measurement of the light orbital angular momentum (OAM) is essential to both the classical and quantum applications with vortex beams. Here, we study the diffraction pattern in the far field when a vortex beam passes through an arc slit and demonstrate experimentally that a light spot of the diffraction pattern has a displacement which is linear to the topological charge (TC) of the incident vortex beam. Based on this property, this method is capable of measuring both modulus and sign of TC of the vortex beam. Furthermore, this scheme allows identifying multiple OAM states simultaneously.

The ability to measure the orbital angular momentum (OAM) distribution of vortex light is essential for OAM applications. Although there have been many studies on the measurement of OAM modes, it is difficult to quantitatively and instantaneously measure the power distribution among different OAM modes, let alone measure the phase distribution among them. In this work, we propose an OAM complex spectrum analyzer that enables simultaneous measurements of the power and phase distributions of OAM modes by employing the rotational Doppler effect. The original OAM mode distribution is mapped to an electrical spectrum of beat signals using a photodetector. The power and phase distributions of superimposed OAM beams are successfully retrieved by analyzing the electrical spectrum. We also extend the measurement technique to other spatial modes, such as linear polarization modes. These results represent a new landmark in spatial mode analysis and show great potential for applications in OAM-based systems and optical communication systems with mode-division multiplexing. An instrument that can map the power and phase distributions of vortex light beams that have orbital angular momentum (OAM) has been built. The ability to measure the OAM distribution of vortex light is essential for OAM applications, but it is challenging to instantaneously measure the power and phase distribution of different OAM modes. The OAM spectrum analyzer developed by Jianji Dong of Huazhong University of Science and Technology and co-workers characterizes a beam with unknown OAM by sending it and a reference beam to a spinning object, which scatters the light, imparting a rotational Doppler frequency shift in the process. The scattered light is then passed through a mode filter and collected by a photodetector for analysis. The frequency shift of the scattered light reveals information about the OAM content of the unknown beam.

Vortex beams with fractional topological charge (FTC) have many special characteristics and novel applications. However, one of the obstacles for their application is the difficulty of precisely determining the FTC of fractional vortex beams. We find that when a vortex beam with an FTC illuminates a dynamic angular double slit (ADS), the far-field interference patterns that include the information of the FTC of the beam at the angular bisector direction of the ADS vary periodically. Based on this property, a simple dynamic ADS device and data fitting method can be used to precisely measure the FTC of a vortex light beam with an error of less than 5%.

When a vortex beam with the spiral phase structure passes through a dynamic angular double slits (ADS), the interference pattern changes alternatively between destructive and constructive at the angular bisector direction of the ADS due to their phase difference. Based on this property, we experimentally demonstrate a simple method, which can precisely and efficiently determine the topological charge of vortex beams. What is more, this scheme allows determining both the modulus and sign of the topological charge of vortex beams simultaneously., Comment: 4 pages, 4 figures