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We present a compact, highly tolerant vertical coupling structure, which can be a generic design that bridges the gap between conventional resonant couplers and adiabatic couplers for heterogeneously integrated devices. We show insights on relaxing the coupler alignment tolerance and provide a detailed design methodology. By the use of a multisegmented inverse taper structure, our design allows a certain proportion of the odd supermode to be excited during the coupling process, which simultaneously facilitates high tolerance and compactness. With a total length of 87 μm, our coupler is almost threefold shorter than the state-of-the-art alignment-tolerant adiabatic couplers and outperforms them by demonstrating a more than 94% coupling efficiency (for < 0.3 dB coupling loss) with ± 1 μm misalignment tolerance, which, to our best knowledge, is a new record for III-V-on-silicon vertical couplers. Furthermore, our design has high tolerance to fabrication-induced structural deformation and ultrabroad bandwidth. These features make it particularly suitable for building densely integrated III-V-on-silicon photonic circuits with commercially available microtransfer printing assembly tools. The proposed design can be widely adopted in various integration platforms.

It is recognized that unknown emissivity and ill-posed radiation equations present significant challenges to light-field multi-wavelength pyrometry. Furthermore, emissivity range and choice of initial value also have a significant impact upon the measurement results. This paper demonstrates that a novel chameleon swarm algorithm approach could be used to ascertain temperature information from light-field multi-wavelength data at a higher accuracy level without prior emissivity knowledge. The performance of chameleon swarm algorithm was experimentally tested and compared with the traditional internal penalty function and generalized inverse matrix-exterior penalty function algorithms. Comparisons of calculation error, time, and emissivity values for each channel show that the chameleon swarm algorithm is superior in terms of both measurement accuracy and computational efficiency.

With rapid developments in light-field particle image velocimetry (LF-PIV) based on single-camera, dual-camera, and dual-camera with Scheimpflug lenses, comprehensive quantitative analysis and careful evaluation of their theoretical spatial resolutions are essential to guide their practical applications. This work presents a framework for and better understanding of the theoretical resolution distribution of various optical field cameras with different amounts and different optical settings in PIV. Based on Gaussian optics principles, a forward ray-tracing method is applied to define the spatial resolution and provides the basis of a volumetric calculation method. Such a method requires a relatively low and acceptable computational cost, and can easily be applied in dual-camera/Scheimpflug LF-PIV configuration, which has hardly been calculated and discussed previously. By varying key optical parameters such as magnification, camera separation angle, and tilt angle, a series of volume depth resolution distributions is presented and discussed. By taking advantage of volume data distributions, a universal evaluation criterion based on statistics that is suitable for all three LF-PIV configurations is hereby proposed. With such a criterion, the pros and cons of the three configurations, as well as the effects of key optical parameters, can then be quantitatively illustrated and compared, thus providing useful guidance on the configuration and optical parameter selections in practical implementations of LF-PIV.

We found that temperature-dependent infrared spectroscopy measurements (i.e., reflectance or transmittance) using a Fourier-transform spectrometer can have substantial errors, especially for elevated sample temperatures and collection using an objective lens. These errors can arise as a result of partial detector saturation due to thermal emission from the measured sample reaching the detector, resulting in nonphysical apparent reduction of reflectance or transmittance with increasing sample temperature. Here, we demonstrate that these temperature-dependent errors can be corrected by implementing several levels of optical attenuation that enable convergence testing of the measured reflectance or transmittance as the thermal-emission signal is reduced, or by applying correction factors that can be inferred by looking at the spectral regions where the sample is not expected to have a substantial temperature dependence.

In this paper, a novel through-silicon via (TSV) structure, named partial coaxial TSV (PC-TSV), is proposed to suppress TSV-induced substrate noise. In this structure, the via is surrounded by a benzocyclobutene (BCB) layer, and a grounded metal ring placed at one end. The BCB layer can effectively reduce the leakage of the signal to the substrate, and the metal ring provides a low impedance path for the substrate noise. An equivalent RLGC model of this structure is also established, and it is verified by simulated result from CST. Then, the performance of PC-TSV is compared with that of the traditional TSV, TSV with p+ layer, and TSV with p+ guard ring. Analysis results in frequency domain indicate PC-TSV has a larger $\vert \text{S}_{21}\vert $ and less near-end crosstalk than other three structures. Additionally, analysis results in time domain show that the substrate voltage noise of this structure is obviously reduced compared with the TSV with p+ layer and TSV with p+ guard ring. Also, a feasible process flow for this structure is given and it is simpler than that for traditional coaxial TSV.

An induced-transmission filter (ITF) uses an ultrathin layer of metal positioned at an electric-field node within a dielectric thin-film bandpass filter to select one transmission band while suppressing other transmission bands that would have been present without the metal layer. Here, we introduce a switchable mid-infrared ITF where the metal film can be "switched on and off", enabling the modulation of the filter response from single-band to multiband. The switching is enabled by a deeply subwavelength film of vanadium dioxide (VO2), which undergoes a reversible insulator-to-metal phase transition. We designed and experimentally demonstrated an ITF that can switch between two states: one broad passband across the long-wave infrared (LWIR, 8 - 12 um) and one narrow passband at ~8.8 um. Our work generalizes the ITF -- previously a niche type of bandpass filter -- into a new class of tunable devices. Furthermore, our unique fabrication process -- which begins with thin-film VO2 on a suspended membrane -- enables the integration of VO2 into any thin-film assembly that is compatible with physical vapor deposition (PVD) processes, and is thus a new platform for realizing tunable thin-film filters., Comment: Main text + supplementary

Mode-division multiplexing can scale the capacity of optical communications and optical interconnects. We demonstrate an ultra-compact and fabrication-error tolerant silicon three-mode multiplexer by shallowly etching rectangular trenches on a multi-mode interferometer. Depending on the selected input port, the TE0 mode is converted to the eigenmodes of the bus waveguide. These modes are coupled to each other owing to the refractive-index perturbation induced by the shallow trenches and finally converted to a selected spatial mode at the output. A three-mode multiplexing device is experimentally demonstrated with a footprint of 2.00 × 17.05 µm2. The bandwidths for the three channels are >70 nm with crosstalk values below –10 dB.

In this paper, through rock core, logging curve, plane shape, distribution and other characteristics in the research area, combined with regional data, the Permo-Carboniferous Strata in the research area experienced tidal flat sedimentary system, delta sedimentary system and river sedimentary system, flood-overlake sedimentary system from bottom to top, it is proved that basin filling evolution of the epicontinental sea basin from occurrence, development to extinction.

Shielded through-silicon vias (S-TSV) filled with multi-walled carbon nanotubes (MWCNT) in the via and the shielded layer, and benzocyclobutene or silicon in the insulation layer is presented in this paper. Then, the equivalent transmission line models of the two S-TSVs are established. Based on the model, the forward transmission coefficient and attenuation constant are calculated and the impact of quantum capacitance C q of MWCNT on the transmission performance of S-TSVs is analyzed. The results indicate that the performance of S-TSVs with Si insulation layer in 0–100 GHz can be significantly improved by C q . Also, the performance of S-TSV filled with BCB above 40 GHz can be improved. In addition, the temperature effect of silicon can be balanced by C q . As a result, the heat stability of S-TSV with silicon insulation layer is improved.

Image space photon mapping has the advantage of simple implementation on GPU without pre-computation of complex acceleration structures. However, existing approaches use only a single image for tracing caustic photons, so they are limited to computing only a part of the global illumination effects for very simple scenes. In this paper we fully extend the image space approach by using multiple environment maps for photon mapping computation to achieve interactive global illumination of dynamic complex scenes. The two key problems due to the introduction of multiple images are 1) selecting the images to ensure adequate scene coverage; and 2) reliably computing raygeometry intersections with multiple images. We present effective solutions to these problems and show that, with multiple environment maps, the image-space photon mapping approach can achieve interactive global illumination of dynamic complex scenes. The advantages of the method are demonstrated by comparison with other existing interactive global illumination methods.

A novel miniature ultra-wideband (UWB) bandpass filter with coplanar waveguide (CPW) fed is proposed. The size of the filter is reduced largely because of combining the wideband couple gap and parallel-coupled CPW line (not cascading multiple resonator), and the length of realized filter is only 0.42 λg0 (λg0 is the guiding wavelength at central frequency). The measured insertion loss is less than 2.0 dB, and the group delay variation is less than 0.2 ns within the UWB passband. Basic agreement between the simulated and measured results has been achieved.

A novel nested structure for designing miniaturized dual-band bandpass filter has been proposed. The two passbands are obtained by nesting two different resonators, and every resonator controls one passband, respectively. The implemented filter operates at 2.4GHz and 5.2 GHz. Due to the nested structure, the dimension of the filter is reduced to 0.15λg 1 ×0.18λg 1 (λg 1 is the guiding wavelength at 2.4GHz). The nested structure can also be employed to achieve triple-band filter. The measured results are in good agreement with the simulated results.

We present a novel technique for real-timely rendering translucent objects. Our technique is mainly based on translucent shadow maps with a new adaptive sampling strategy. In this sampling strategy, the hierarchy levels and positions for sampling are selected according to the size of target object. By our optimization, less storage in the texture is required than that in previous methods. Compared with previous methods, our technique provide a way to choose the proper sampling pattern and is applicable for a wider range of object sizes. With the implementation on GPU, the presented technique is able to render translucent objects in animated scenes where lights and material parameters vary real-timely without any lengthy preprocessing.

In this paper, by analyzing the coal mine safety accident of present stage, the author has come to a conclusion that the safe accidents on coalface accounting for a lot of coal mine safety accident, and has brought forward the cause leading to this phenomenon. Then, through the discussion about “Overlying Strata Movement Law”, this author has suggested that Electronic Business can be used for the coal mine to prevent and control safe accident on coalface, and has given out the operating pattern of Electronic Business innovatively. This conclusions are most instructive to Chinese coal mine in managing safe accident on coalface and innovative for application of Electronic Business in coal mine safety.

This paper introduces a three-port microstrip diplexer. The diplexer is made up of two band-pass filters based on symmetric microstrip electromagnetic band gap (EBG) structure and two 1/4 lambda micro-strips (lambda is the guiding wavelength at the resonant frequency of every filter.) The result of simulation shows that the micro-strip diplexer has excellent performances of lower insertion loss and higher suppression band-stop. Also, the second harmonic falls into the stopband and can be suppressed directly.

We describe and demonstrate general procedures for thermal-emission measurements that are applicable to most experimental conditions, including more-challenging cases such as thermal emitters with temperature-dependent emissivity and emitters that are not in thermal equilibrium.