Progress in Quantum Electronics最新文献

Owing to their novel physical properties, semiconductors have penetrated almost every corner of the contemporary industrial system. Nowadays, semiconductor materials and their microelectronic and optoelectronic devices are widely used in civil and military fields. Recently, ultrawide-bandgap (UWBG) semiconductors with bandgaps considerably wider than 3.4 ​eV of GaN, such as aluminium gallium nitride (AlGaN), gallium oxide (Ga₂O₃), and diamond, have attracted increasing attention due to their advantages, including high breakdown field, high stability, and high radiation resistance. In this review, recent research pertaining to UWBG semiconductors in optoelectronics and microelectronics is introduced. Moreover, the challenges and opportunities of UWBG semiconductors are deliberated. It is expected that this review will provide inspiration and insights for further related research.

Chiral organic–inorganic hybrid metal halides (HMHs), as an emerging class of chiral semiconductor materials, have attracted unparalleled interest from multi-purpose perspectives, as a result of their easily accessible solution-grown methods, plentiful chemical structure and composition, as well as unique and exciting optoelectronic properties. Recently, substantial progress has been made in the synthesis of chiral HMHs, spectroscopic characterization and fabrication of optoelectronic devices. Although several reviews about the chiroptical properties and applications of chiral HMHs have been published, the comprehensive summary of the basic structural frameworks, fundamental physics and strategies for the modulation of optical activity, which are vital for the design of chiral HMHs and development of relevant optoelectronic applications, are still insufficient. In this review, we summarize the research progress from fundamentals to applications for the single crystals and thin films of chiral HMHs that are conducive to the development of practical optoelectronic devices. First, diverse structural frameworks and synthetic methods of chiral HMHs are systematically summarized. Afterward, fundamental physics and strategies for the modulation of optical activity as well as their related optoelectronic applications are comprehensively reviewed. Finally, we put forward the current challenges in this rapidly evolving field and present an outlook on future prospects to further develop chiral HMHs for various applications.

The measurement of optical ultrafast laser pulses is done indirectly because the required bandwidth to measure these pulses exceeds the bandwidth of current electronics. As a result, this measurement problem is often posed as a 1-D phase retrieval problem, which is fraught with ambiguities. The phase retrieval method known as ptychography solves this problem by making it possible to measure ultrafast pulses in either the time domain or the frequency domain. One well known algorithm is the principal components generalized projections algorithm (PCGPA) for extracting pulses from Frequency-Resolved Optical Gating (FROG) measurements. Here, we discuss the development of the PCPGA and introduce new developments including an operator formalism that allows for the convenient addition of external constraints and the development of more robust algorithms. A close cousin, the ptychographic iterative engine will also be covered and compared to the PCGPA. Additional developments using other algorithmic strategies will also be discussed along with new developments combining optics and high-speed electronics to achieve megahertz measurement rates.

The concept of tunneling injection was introduced in the 1990's to improve the dynamical properties of semiconductor lasers by avoiding the problem of hot carrier injection which increase the gain nonlinearity and hence limit the modulation capabilities. Indeed, tunneling injection led to record modulation speeds in quantum well lasers. Employing tunneling injection in quantum dot lasers is significantly more complicated. Tunneling injection is based on an energy band alignment between a carrier reservoir and the active region where laser oscillation takes place. However, the inherent inhomogeneity of self-assembled quantum dots prevents an unequivocal band alignment and can cause the tunneling injection process to actually deteriorate the laser performance compared to nominally identical quantum dot lasers that have no tunneling section. Understanding the complex process of tunneling injection in quantum dot lasers requires a comprehensive study where different aspects are analyzed theoretically and experimentally. In this paper we describe the technology of such lasers in the InP material system followed by a microscopic analysis of the detailed electrical characterization which is correlated to the electro-optic properties yields information about the exact carrier transport mechanism at bias levels of almost zero to well above threshold. A tunneling injection quantum dot optical amplifier was used for multi wavelength pump probe characterization from which it is clear why tunneling injection often deteriorates laser performance and determines how to design a structure which can take advantage of tunneling injection. Finally, we present a direct comparison between the modulation response of a tunneling injection quantum dot laser and a twin structure that has no tunneling injection section.

The broad study sheds light on the fundamental tunneling injection process that can guide the design of an optimum laser where tunneling injection will be taken full advantage of and will improve the dynamical properties.

We present a review on the photoionization bands that can be found in the far ultraviolet part of the spectrum using all sapphire cells in absorption experiments with hot alkali vapor. We describe cesium and rubidium dimers which have very pronounced photoionization bands together with bialkali mixtures like KCs and RbCs. We explain the origin of these peculiar bands as special molecular transitions between the ground state of the neutral molecule and exited states of the ionized molecule as a direct ionization process. We also described the diffuse bands as transition from the same ground state molecule to doubly excited molecular state, as an indirect ionization process. Finally, we believe that these two pathways may interfere resulting in a complex structure revealing the observed diffuse bands.

Over the past few decades, optoelectronic devices have played a key role in human life and modern technology. To meet the development trends of the industry, photonics with tunable functions have emerged as building blocks with immense potential in controlling light–matter interactions, sensors, and integrated photonics. Compared with artificially designed materials and physical approaches, stimuli-responsive biointerfaces enable a higher level of functionalities and versatile means to tailor optical responses at the nanoscale. Recent advances in biological tunable photonics have attracted tremendous attention owing to the incorporation of living biomaterials into organic photonic and photoelectric devices. In this review, we highlight the advances made in biological tunable photonics during the past five years. We begin with an overview of the competency of natural biological materials, followed by the introduction of key stimuli that have a dominant influence on the development of active biointerfaces. Lastly, we present a comprehensive summary of optoelectronic applications that utilize living biomaterials as active controls. Such applications include bioactivated light-emitting diodes, biological lasers, active plasmonics, robotics, biological logic gates, light-harvesting antennas, molecular photonic wires, bioenergy, and biophotovoltaics. The opportunities and challenges for future research directions are also briefly discussed.

The terahertz (THz) quantum cascade laser (QCL), first demonstrated in 2002, is among the most promising radiation sources in the THz region owing to its high output power and broad frequency coverage from ∼1.3 to ∼5.4 ​THz and sub-terahertz, without and with assistance of external strong magnetic field. The operation of THz QCLs, however, has thus far been limited to applications below room temperature. Recent advances in THz QCL research have principally focused on optimization of quantum design, fabrication, and growth techniques to improve the maximum operating temperature of THz QCLs; these efforts culminated in a recent demonstration of pulse-mode lasing at temperature up to 250 ​K. Research interests continue to be propelled as new maximum lasing temperature record are set, heating up the race to realize room-temperature operation of THz QCLs. This paper critically reviews key achievements and milestones of quantum designs, fabrication techniques, and simulation methods applicable to the high temperature operation of THz QCLs. In addition, this paper provides a succinct summary of efforts in this field to pinpoint the remaining challenges and provide a comprehensive picture for future trends in THz QCL research.

Photonic spin and orbital angular momenta, which are determined by the polarization and spatial degrees of freedom of photons, are strongly coupled with each other in subwavelength structured metasurfaces. The photonic spin-orbit interaction (PSOI) results in the splitting of the degenerated system states. In this review, we focus on the principles of symmetric PSOI associated with the conjugated geometric phase modulation as well as the asymmetric PSOI resulting from the additional localized phase manipulation. Recent advances and important applications of symmetric and asymmetric PSOI in metasurfaces are also discussed. We finally highlight with our perspective on the remaining challenges and future trends in this field.

Random Lasers (RLs) and Random Fiber Lasers (RFLs) have been the subject of intense research since their first experimental demonstration in 1994 and 2007, respectively. These low coherence light sources rely on multiple scattering of light to provide optical feedback in a medium combining a properly excited gain material and a scattering disordered structure. It is the feedback mechanism which makes RLs/RFLs quite different from conventional lasers, with the later relying on an optical cavity usually formed by two static mirrors. This characteristic makes the RLs and RFLs devices to become cavityless, although not modeless, and present features of complex systems, whose statistics of intensity fluctuations are quite relevant. In addition, RLs can be designed in three-dimensional (3D) geometry, typically powders or colloids, in two-dimensional (2D) geometries, such as planar waveguides or thin-films, and one-dimensional (1D or quasi-1D) geometry, generally in optical fibers, known as the RFLs. The advantage of 1D geometry is the inherent directionality of the RFL emission, which otherwise is multidirectional in 3D geometry. In this review paper, we initially describe the basic theoretical framework supporting laser emission due to feedback in disordered structures. We then provide an updated vision of the types of RLs and RFLs that have been demonstrated and reported, from dyes solutions embedded with nano/submicron-scatterers composites to rare-earth doped micro or nanocrystals and random fiber Bragg gratings as the scattering structure. The influence of optical processes due to second-, third- and high-order nonlinearities on the intensity behavior of RLs are discussed. Subsequently, we review multidisciplinary studies that lead to the classification of RLs as complex systems exhibiting turbulence-like characteristics, photonic phase-transitions presenting replica symmetry breaking and intensity fluctuations satisfying Lévy-like statistics, and the so-called Floquet phase. Furthermore, we also highlight technological applications that includes sensing, optical amplification, and biomedical imaging. The review concludes pointing out potential directions in basic and applied research in the field of RL and RFL.