Showing papers in "Advances in Optics and Photonics in 2013"

Three-dimensional display technologies

Abstract: The physical world around us is three-dimensional (3D), yet traditional display devices can show only two-dimensional (2D) flat images that lack depth (i.e., the third dimension) information. This fundamental restriction greatly limits our ability to perceive and to understand the complexity of real-world objects. Nearly 50% of the capability of the human brain is devoted to processing visual information [Human Anatomy & Physiology (Pearson, 2012)]. Flat images and 2D displays do not harness the brain's power effectively. With rapid advances in the electronics, optics, laser, and photonics fields, true 3D display technologies are making their way into the marketplace. 3D movies, 3D TV, 3D mobile devices, and 3D games have increasingly demanded true 3D display with no eyeglasses (autostereoscopic). Therefore, it would be very beneficial to readers of this journal to have a systematic review of state-of-the-art 3D display technologies.

The Talbot effect: recent advances in classical optics, nonlinear optics, and quantum optics

Abstract: The Talbot effect, also referred to as self-imaging or lensless imaging, is of the phenomena manifested by a periodic repetition of planar field distributions in certain types of wave fields. This phenomenon is finding applications not only in optics, but also in a variety of research fields, such as acoustics, electron microscopy, plasmonics, x ray, and Bose–Einstein condensates. In optics, self-imaging is being explored particularly in image processing, in the production of spatial-frequency filters, and in optical metrology. In this article, we give an overview of recent advances on the effect from classical optics to nonlinear optics and quantum optics. Throughout this review article there is an effort to clearly present the physical aspects of the self-imaging phenomenon. Mathematical formulations are reduced to the indispensable ones. Readers who prefer strict mathematical treatments should resort to the extensive list of references. Despite the rapid progress on the subject, new ideas and applications of Talbot self-imaging are still expected in the future.

Inducing and harnessing stimulated Brillouin scattering in photonic integrated circuits

Abstract: We review recent progress in inducing and harnessing stimulated Brillouin scattering (SBS) in integrated photonic circuits. Exciting SBS in a chip-scale device is challenging due to the stringent requirements on materials and device geometry. We discuss these requirements, which include material parameters, such as optical refractive index and acoustic velocity, and device properties, such as acousto-optic confinement. Recent work on SBS in nano-photonic waveguides and micro-resonators is presented, with special attention paid to photonic integration of applications such as narrow-linewidth lasers, slow- and fast-light, microwave signal processing, Brillouin dynamic gratings, and nonreciprocal devices.

Terahertz dielectric waveguides

Abstract: Several classes of non-planar metallic and dielectric waveguides have been proposed in the literature for guidance of terahertz (THz) or T-ray radiation. In this review, we focus on the development of dielectric waveguides, in the THz regime, with reduced loss and dispersion. First, we examine different THz spectroscopy configurations and fundamental equations employed for characterization of THz waveguides. Then we divide THz dielectric waveguides into three classes: solid-core, hollow-core, and porous-core waveguides. The guiding mechanism, fabrication steps, measured loss, and dispersion are presented for the waveguides in each class in chronological order. The goal of this review is to compare and contrast the current solutions for guiding THz radiation.

Application of space–time duality to ultrahigh-speed optical signal processing

Abstract: Manipulation and characterization of information using ultrafast optical signals is critical for numerous applications in telecommunications, biology, quantum information science, spectroscopy, and atomic and molecular physics. Femtosecond pulsed laser sources are available over a wide range of wavelengths and repetition rates, which enable the generation, transmission, and characterization of information at bandwidths beyond 1 THz. In this article, we review the concept of space–time duality as a system design tool for ultrafast optical processing and characterization. The combination of this design framework with recent advances in nonlinear optical devices enables the realization of highly complex signal processing systems that can generate, characterize, and manipulate arbitrary and non-repetitive optical waveforms at unprecedented processing speeds.

Spin-noise spectroscopy: from proof of principle to applications

Abstract: More than 30 years ago, the feasibility of detecting magnetic resonance in the Faraday-rotation noise spectrum of transmitted light was demonstrated experimentally. However, practical applications of this experimental approach have emerged only recently thanks, in particular, to a number of crucial technical advancements. This method has now become a popular and efficient tool for studying magnetic resonance and spin dynamics in atomic and solid-state paramagnets. In this paper, we present a review of research in the field of spin-noise spectroscopy, including its physical basis, its evolution since its first experimental demonstration, and its recent experimental advances. Main attention is paid to the specific capabilities of this technique that render it unique compared to other methods of magnetic and optical spectroscopy. The paper is primarily intended for experimentalists who may wish to use this novel optical technique.

Semiconductor nanowire lasers

Abstract: Semiconductor nanowires (or other wire-like nanostructures, including nanoribbons and nanobelts) synthesized by bottom-up chemical growth show single-crystalline structures, excellent geometric uniformities, subwavelength transverse dimensions, and relatively high refractive indices, making these one-dimensional structures ideal optical nanowaveguides with tight optical confinement and low scattering loss. When properly pumped by optical or electrical means, lasing oscillation can be readily established inside these high-gain active nanowires with feedback from endface reflection or near-field coupling effects, making it possible to realize nanowire lasers with miniature sizes and high flexibilities. Also, the wide-range material availability bestows the semiconductor nanowire with lasing wavelength selectable within a wide spectral range from ultraviolet (UV) to near infrared (IR). As nanoscale coherent light sources, in recent years, nanowire lasers have been attracting intensive attention for both fundamental research and technological applications ranging from optical sensing, signal processing, and on-chip communications to quantum optics. Here, we present a review of the status and perspectives of semiconductor nanowire lasers, with a particular emphasis on their optical characteristics categorized in two groups: (1) waveguiding related properties in Section 3, which includes waveguide modes, near-field coupling, endface reflection, substrate-induced effects, and nanowire microcavities, and (2) optically pumped semiconductor nanowire lasers in Section 4, starting from principles and basic types of UV, visible, and near-IR nanowire lasers relying on Fabry–Perot cavities, to advanced configurations including wavelength-tunable, single-mode operated, fiber-coupled, and metal-incorporated nanowire lasing structures for more possibilities. In addition, the material aspects of semiconductor nanowires, including nanowire synthesis and electrically driven nanowire lasers, are briefly reviewed in Sections 2 and 5, respectively. Finally, in Section 6 we present a brief summary of semiconductor nanowire lasers regarding their current challenges and future opportunities.

Low-noise optical amplification and signal processing in parametric devices

Abstract: Recent progress in low-noise optical amplification and signal processing has raised prospects of practical devices operating below the conventional quantum limit. We review the basic principles, practical implementation, and performance of such devices. In particular, we focus on the operation and limitations of χ(3)-based nonlinear platforms, such as silica high-confinement fiber. Classified by the parametric process application, we discuss the use of low-noise parametric mixers as optical amplifiers, phase regenerators, wavelength converters, and signal multicasters.

Theory of Molecular Nonlinear Optics

Abstract: The theory of molecular nonlinear optics based on the sum-over-states (SOS) model is reviewed. The interaction of radiation with a single wtpisolated molecule is treated by first-order perturbation theory, and expressions are derived for the linear (αij) polarizability and nonlinear (βijk, γijkl) molecular hyperpolarizabilities in terms of the properties of the molecular states and the electric dipole transition moments for light-induced transitions between them. Scale invariance is used to estimate fundamental limits for these polarizabilities. The crucial role of the spatial symmetry of both the single molecules and their ordering in dense media, and the transition from the single molecule to the dense medium case (susceptibilities χij(1), χijk(2), χijkl(3)), is discussed. For example, for βijk, symmetry determines whether a molecule can support second-order nonlinear processes or not. For asymmetric molecules, examples of the frequency dispersion based on a two-level model (ground state and one excited state) are the simplest possible for βijk and examples of the resulting frequency dispersion are given. The third-order susceptibility is too complicated to yield simple results in terms of symmetry properties. It will be shown that whereas a two-level model suffices for asymmetric molecules, symmetric molecules require a minimum of three levels in order to describe effects such as two-photon absorption. The frequency dispersion of the third-order susceptibility will be shown and the importance of one and two-photon transitions will be discussed.

Modeling photonic crystal interfaces and stacks: impedance-based approaches

Abstract: In many research areas, the reflective properties of a bulk medium are characterized by its impedance or an impedance-like quantity. Such a quantity is essential for the efficient design of stacked structures such as antireflection coatings and thin-film filters. For 2D photonic crystals and metamaterials, the literature contains multiple definitions of impedance, not all of which are consistent. We review these proposed definitions, evaluate their regions of applicability, and numerically test their accuracy in a variety of salient photonic crystal examples.