Progress in Quantum Electronics最新文献

Blue LEDs and HEMTs based on III-Nitride have been flourishing commercially across the globe, thanks largely to breakthroughs in the material quality of the wide-bandgap compound semiconductor back in the 1990s. The realizations of white-light LEDs, blu-ray systems, and lately efficient compact chargers have drastically changed the way we live and have contributed tremendously to global energy saving efforts. The maturity and diversity of modern discrete GaN-based devices open up opportunities for an integrated GaN platform with extended functionalities and applications. In this review paper, we present an overview of the monolithic and heterogeneous integration of GaN devices and components. Various methods for the integration of electronic, optoelectronic, and optical components based on GaN are discussed.

This paper reviews the field of microwave photonics instantaneous frequency measurements (IFM). It aims to consolidate the literature, explains the key implementations and reviews the recent developments. Current photonic IFMs are capable of operating over a wide bandwidth with a good resolution. However, their implementations are often based on discrete components and exhibit limited dynamic range and moderate efficiency. Photonic integration and improvements of dynamic range and efficiency are thus necessary, and they are anticipated as the future research directions and developments.

The development of the HgCdTe alloy as the most important intrinsic semiconductor for infrared (IR) technology is well established and recognized. In spite of the achievements in material and device quality, the drawbacks still exist due to bulk and surface instability, lower yields and higher costs particularly in fabrication of long wavelength infrared arrays. The difficulties with this material encouraged to research on other compounds to improve device performance.

Since the first paper published by Sakaki and Esaki in 1978 it is well known that InAs and GaSb constitute a nearly lattice-matched material system offering great flexibility in the design of IR optoelectronic devices. After four decades, the III-V type-II superlattice (T2SL) detector technology is under strong development as a possible alternative to HgCdTe. The novel ideas coming in design of detectors have enhanced the position of T2SLs in IR materials detector technology. It appears that T2SLs are especially helpful in the design of unipolar barriers.

In this paper fundamental physical properties of two material systems, HgCdTe and T2SLs, are compared together with their influence on detector performance: dark current density, RA product, quantum efficiency, and noise equivalent different temperature. In comparison with HgCdTe, fundamental properties of T2SLs are inferior. On the other hand, T2SL and barrier detectors have several advantages to include lower tunnelling and surface leakage currents, and suppressed Auger recombination mechanism. Up to date, the promise of superior performance of these detectors has not been realized yet. In the paper we present that the performance of T2SL detectors (dark current, current responsivity, and noise equivalent difference temperature) is lower than bulk HgCdTe photodiodes.

Due to stronger, less ionic chemical bonding of III-V semiconductors, these materials are attractive due to manufacturability and stability. It is also predicted that the interband T2SL quantum cascade devices will outperform the performance of the high operating temperature HgCdTe detectors.

Recent advances in the development of quantum dots (QDs) have offered new possibilities for the exploration of sensors, bio imaging, batteries, electrochemical water splitting and optoelectronic applications because of their intriguing optical, electrical, catalytic and electrochemical properties. Among QDs, atomically thin two-dimensional quantum dots (2D QDs) derived from graphene sheets, transition metal dichalcogenide (TMD) layers and phosphorene have been of considerable interest for the past few years. There have been several intensive studies of carbon QDs, but TMD QDs and heterostructures based on 2D QDs are rapidly advancing. Herein, the synthesis and properties of 2D QDs, particularly carbon and TMD QDs, are reviewed for the recent progress in their application toward electrochemical water splitting, photocatalytic wastewater treatment, supercapacitors, batteries and photodetectors. Moreover, the assembly of such 2D QDs to achieve industrial-scale production and boost their performance in widespread applications is emphasized.

Cr: Colquiriite laser materials (Cr:LiCAF, Cr:LiSAF, Cr:LiSGaF) own broad absorption bands in the visible region that allow direct-diode pumping by well-developed low-cost red diodes. Moreover, they possess broad emission bands in the near infrared that enable widely tunable laser operation (720–1110 nm), and generation of sub-10-fs light pulses via mode-locking. Furthermore, Cr: Colquiriite crystals can be grown with a very low loss level of 0.2%/cm, which enables the construction of high-Q-cavities, resulting in lasing thresholds below 1 mW, and slope efficiencies above 50%. High-Q-cavities constructed with Cr: Colquiriites could store large amount of intracavity laser powers which is off great interest: (i) for increasing the efficiency of intracavity nonlinear processes such as intracavity frequency-doubling, and (ii) for minimizing laser noise such as timing jitter noise in femtosecond operation. However, thermally and mechanically Cr: Colquiriites have glass like properties. Hence, average power scaling has been challenging in the cw and femtosecond Cr: Colquiriite lasers, as well as in their amplifiers. In this paper, we will review research efforts over the last decades, in developing robust, low-cost, highly-efficient, and tunable cw and femtosecond laser sources based on diode-pumped Cr:Colquiriite gain media. Challenges for future progress will also be discussed.

Visible wavelength light-emitting diodes (LEDs) and laser diodes (LDs) enabled optical wireless communication (OWC) is an emerging technology for realizing high-confidentiality and high-speed point-to-point (PtP), vehicle-to-vehicle, and white-lighting data access links in indoor/outdoor free-space and underwater environments. Notably, OWC facilitates users to access more transmission bandwidth and capacity with physical-layer security and electromagnetic-immunity features by utilizing unlicensed visible optical carriers bands covering from 400 to 800 THz as compared to the commonly employed radio-frequency bands. Hence, a large amount of heavy data exchanging, routing, and streaming traffics can be realized in the current wireless networks. This also reinforces the realistic fusion of optical fiber wireline, radio-frequency wireless, and visible lighting communication networks in the new big-data era. In this paper, developing progress as well as the current trend of visible LED and LD based OWC networks for PtP, white-lighting and underwater applications are overviewed in detail. The performance parameters and figures-of-merits of previously reported OWC systems are summarized for comparison and discussion. Three main scenarios including visible LED based lighting OWC, visible LD enabled PtP communication, and LD based white-light fidelity (“Li-Fi”) are individually discussed and summarized with their allowable data rate, transmission distance, and lighting color temperature and rendering index for comparison. At first, the transmission performances of LED based PtP and white-lighting OWC system with the use of novel data formats, such as pulse amplitude modulation and quadrature amplitude modulation-orthogonal frequency division multiplexing, are surveyed to understand the increasing trend on transmission capacity of LED based OWC system. Owing to the limited bandwidth and data rate of LED based OWC system, the LD has gradually been regarded as a competitive alternative candidate transmitter due to their significantly broadened bandwidth and enhanced data capacity. By taking the aforementioned advantages, studies on the blue/violet LD based white-lighting OWC have recently emerged to demonstrate the substitutability of this technology. The impacts of LD based OWC technology with its state-of-the-art implementation are comprehensively discussed together with prospects for future developments. Undoubtedly, the blue/violet LDs are also a promising transmitter for underwater PtP transmission owing to its extremely low power extinction in water, which has recently emerged as the most intriguing source for undersea exploration and sensing applications.

Electromagnetic (EM) metamaterials are artificially engineered media composed of subwavelength unit cells, which achieve exotic EM properties beyond the limits of natural materials and provide great freedom to manipulate EM waves. Here, we review the recent progress on metamaterials in terms of three aspects: effective medium metamaterials, plasmonic metamaterials, and information metamaterials, respectively. In the first section for the effective medium metamaterials, we summarize the fundamental physics and typical applications such as invisibility cloaks, lenses, antennas, and other passive devices. Tunable, reconfigurable, and active metamaterials are also introduced. In the second section, we review the research progress of single plasmons at optical frequencies, and then present highly efficient excitation methods of spoof surface plasmon polaritons (SPPs) and introduce typical passive and active SPP devices such as waveguides, beam splitters, filters, directional couplers, amplifiers, and second harmonic generators. SPP on-chip components and circuits are also investigated with the remarkable advantages in crosstalk reduction to solve the signal-integrity problem, which has challenged to the microwave devices and integrated circuit technologies for many years. Subsequently, spoof localized surface plasmons (LSPs) having novel resonant modes and potential application in high sensitivity sensors are illustrated. In the third section, we first give a brief introduction of EM metasurfaces as well as their applications in generation of optical vortex beams, holograms, and metalenses, and then give a comprehensive review on the recently proposed information metamaterials, including digital coding metamaterials and field-programmable metamaterials, by taking account of the physical principles and their new functions in real-time manipulation of the EM waves such as anomalous reflections or refractions, radar cross section (RCS) reductions, and beam scanning. We further demonstrate the applications of programmable metamaterials in programmable radar, imaging, wireless communication, and hologram systems. Finally, an outlook of the future directions of metamaterials is offered.

Development of Si photonic integrated circuits (PICs) has been impeded due to lack of efficient Si-based light-emitting sources. Because of their indirect bandgap, bulk Ge and Si are very inefficient at emitting light. Therefore, direct-bandgap III-V semiconductors have been extensively exploited for the active region of the lasers for PICs. Heterogeneous and monolithic integration of III-V semiconductor components on Si platforms have been considered as promising solutions to achieve practical on-chip light-emitting sources for Si photonics. This paper reviews the latest developments on telecommunication wavelength III-V lasers integrated on Si substrates, in terms of integration methods and laser performance.

Plasmons, the electromagnetic excitations coupled with electron waves, possess the intrinsic ability of manipulating light at subwavelength scales down to picometer. This ability not only helps uncovering the fascinating quantum behaviors that strengthen the basic understanding of quantum science, but also enables the inventions of various quantum optoelectronic devices, triggering the birth of quantum plasmonic technology. The past decade has witnessed the flourishing of this technology. In this review, we first focus on fundamental investigations into quantum behaviors for both “isolated” plasmonic nanostructures and “coupled” plasmon-emitter systems, emphasizing new theoretical frameworks and experimental advances. Leveraging on these fundamentals, the progress in exploring and applying quantum plasmonic devices is discussed, such as quantum plasmonic circuits, nanolasers, biochemistry, and spin-orbit interaction devices. Upon summarizing the past and present developments, the future research directions and promising applications are highlighted.