Diamond Materials (Germany)

Recent advancements in indirect-drive inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF) have achieved a significant milestone by demonstrating target gains greater than one, yet future applications necessitate much higher target gains. One approach to achieving improved implosion performance is to pursue increased fuel compression via a lowered implosion adiabat. Experiments have been performed testing a reduced adiabat by introducing small changes to the drive laser pulse shape and the resulting shock timing for an existing implosion design at 1.9 MJ laser drive with near-ignition performance (experiment N210808). Experiments using the updated design demonstrate, for the very first time, increased compression and fusion yield in ICF implosions on the NIF by using a lower fuel adiabat, and increased compression with a reduced adiabat in high-density carbon ablators. Compared to the previously best-performing experiment with a laser energy of 1.9 MJ, these experiments exhibit increases of up to 80% and 14% in nuclear fusion yield and fuel compression, respectively, and with repeatable performance. Further, it is the only implosion design to have achieved a target gain exceeding one with a laser energy of less than 2 MJ. These findings highlight the efficacy of reduced adiabat designs in achieving higher compression and fusion yields, offering a promising pathway for future ICF applications. This Letter not only addresses a long-standing question in ICF but also paves the way for achieving higher target gains with optimized implosion strategies.

Diamond is a wide bandgap semiconductor and is expected to be applied to power and high-frequency devices due to its high physical properties. In 2016, we reported the first inversion channel diamond MOSFET with normally-off operation and field-effect mobility ( μ FE ) of 8 cm 2 /Vs and then have developed the diamond MOSFET-related technologies. However, the μ FE of the inversion channel diamond MOSFET is 20 cm 2 /Vs, which is still lower than the ideal channel mobility of 3000 cm 2 /Vs. One of the main reasons for the low mobility is the high interface state density ( D it ) of 10 13 cm −2 eV −1 or more generated by the bunching step on the diamond surface. In this study, in order to reduce D it and improve μ FE , we propose the fabrication process of an inversion channel p-type diamond MOSFET with atomically step-free Al 2 O 3 /diamond (111) interface and demonstrate the step-free interface diamond MOSFET. The step-free diamond MOSFET showed normally-off, gate voltage control, and clear saturation characteristics. The μ FE and D it of the step-free diamond MOSFET were 30.6 cm 2 /Vs and 2.8 × 10 12 cm −2 eV −1 , respectively. The D it values are the lowest among the inversion channel diamond MOSFET reported to date for inversion channel MOSFET using an Al 2 O 3 /diamond interface.

Single-color centers in thin polycrystalline diamond membranes allow the platform to be used in integrated quantum photonics, hybrid quantum systems, and other complex functional materials. While single-crystal diamond membranes are still technologically challenging to fabricate as they cannot be grown on a non-diamond substrate, free-standing polycrystalline diamond membranes can be conveniently fabricated at large-scale from nanocrystalline diamond seeds on a substrate that can be selectively etched. However, their practical application for quantum photonics is so far limited by crystallographic defects, impurities, graphitic grain boundaries, small grain sizes, scattering loss, and strain. In this paper, we report on a single-photon source based on silicon-vacancy color centers in a polycrystalline diamond membrane. We discuss the spectroscopic approach and quantify the photon statistics, obtaining a g2(0) ≈ 0.04. Our findings hold promise for introducing polycrystalline diamond to quantum photonics and hybrid quantum systems.

This paper proposes a zero-voltage switching (ZVS) scheme for a dual active bridge (DAB) converter in the full load range. The switching state of the DAB converter with a phase-shift control becomes a hard switching state under an input and output voltage imbalance or light load. Thus, the proposed method regulates the phase-shift angle, output voltage angle of full-bridge circuits, and switching frequency to achieve ZVS for the DAB converter. The DAB converter implementing the proposed ZVS scheme is applied to vehicle-to-home (V2H) systems. Experimental results reveal that a V2H unit using the DAB converter achieves an efficiency 97.2% with the proposed ZVS scheme.

In this paper we describe and demonstrate a new remote in-service monitoring technique for passive optical access networks. New microwatt off-grid powered devices are introduced that may be installed at any location in the network. These monitors are equipped with a unique software-defined address, allow status monitoring of network parameters, facilitate the integration of remote active elements such as switches, and scale up easily to thousands of devices. Such monitors may be used to identify and measure the power levels and connection availability of a customer’s site independent of the subscribers’ optical network termination (ONT). Even physical disconnection of a rogue or erroneous ONT is demonstrated. A hardware implementation using off-the-shelf components together with a special communication protocol was successfully demonstrated in a gigabit passive optical network (GPON) testbed, where random data were transmitted. The lowest power consumption with less than 2 μW allows for powering with an optical supply channel or a small battery that lasts for a decade.

Diamond-coated drawing dies are considered as ideal drawing dies for their unique characteristics, such as high hardness, wear resistance and low friction. In order to utilize the superior characteristics of diamond coatings towards improving the drawing performance, the nonlinear FEM simulation is used to simulate the whole low carbon steel tube hollow sinking process, with 2D axi-symmetric elastic-plastic element. Based on the simulation results, the distributions of the axial stress and radial stress are analyzed, the influence of parameters of drawing dies on the diameter shrinkage is investigated. Optimal die parameters are obtained.