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This paper reviews the past, present and prospective future of silicon optical fibres. The incorporation of silicon with its rich optoelectronic functionality into existing glass fibre technologies presents a route to controlling and manipulating the transmitted light in an unprecedented manner – opening the door to new and wide-ranging applications. Currently, there are two main fabrication approaches to producing these fibres – one involving chemical deposition inside glass capillary templates and the other a more traditional drawing tower technique starting from a rod-in-tube preform – each of which offers different advantages in terms of the material, geometry and waveguiding properties. As 2016 represents the 10th anniversary of the first silicon optical fibre, it is timely to evaluate and speculate on the future of this technology – in all its forms.

The influence of doping the transition metal Zn(II) on potassium hydrogen phthalate (KHP) crystals has been studied. A close observation of FT-IR and XRD profiles of doped and undoped samples reveals some minor structural variations. It appears that the crystal undergoes considerable lattice stress as a result of doping the bivalent zinc. Furthermore, the possibility of cation vacancies aroused owing to the substitution of K1+ by Zn2+ could result in a defective crystal system. Energy dispersive spectra reveal the incorporation of Zn(II) in the crystalline matrix of KHP crystals. Differential scanning calorimetry (DSC) and TG-DTA studies reveal the purity of the sample and no decomposition is observed below the melting point. Small quantity additions of Zn(II) enhance the fluorescence intensity of KHP crystals. The doping results in morphological changes and significantly improves the second harmonic generation (SHG) efficiency of the host crystal.

Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles because their interaction with freely propagating light is omnidirectional. Here, we present unidirectional emission of a single emitter by coupling to a nanofabricated Yagi-Uda antenna. A quantum dot is placed in the near field of the antenna so that it drives the resonant feed element of the antenna. The resulting quantum-dot luminescence is strongly polarized and highly directed into a narrow forward angular cone. The directionality of the quantum dot can be controlled by tuning the antenna dimensions. Our results show the potential of optical antennas to communicate energy to, from, and between nano-emitters.

Holographic telepresence demonstrated A practical method of producing truly three-dimensional images that do not require the viewer to wear special eyewear would have many potential applications - in telemedicine, mapping and entertainment, for instance. True 3D holographic displays have so far lacked the capability of updating images with sufficient speed to convey movement. Now, a team working at the University of Arizona's College of Optical Sciences and Nitto Denko Technical Corporation in Oceanside, California, has developed a system that updates images at close to real-time. In a proof-of-concept experiment, they adapt an established technique based on holographic stereographic recording and a novel photorefractive polymeric material as the recording medium to produce a holographic display that can refresh its images every two seconds. Multicoloured and full parallax display are possible in this system - as is 3D 'telepresence', in which data describing holographic images from one location are transmitted to another location where the images are 'printed' with the quasi-real time dynamic holographic display. Holographic displays can produce truly three-dimensional (3D) images, but have so far been unable to update images fast enough. These authors have adapted a previous technique, based on holographic stereographic recording with a photorefractive polymeric material as the recording medium, to produce a quasi-real-time holographic display that can refresh its images every two seconds, and use it to demonstrate the possibility of 3D telepresence. Improvements could bring applications in telemedicine, prototyping, advertising, updatable 3D maps and entertainment. Holography is a technique that is used to display objects or scenes in three dimensions. Such three-dimensional (3D) images, or holograms, can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. The concept of 3D telepresence, a real-time dynamic hologram depicting a scene occurring in a different location, has attracted considerable public interest since it was depicted in the original Star Wars film in 1977. However, the lack of sufficient computational power to produce realistic computer-generated holograms 1 and the absence of large-area and dynamically updatable holographic recording media 2 have prevented realization of the concept. Here we use a holographic stereographic technique 3 and a photorefractive polymer material as the recording medium 4 to demonstrate a holographic display that can refresh images every two seconds. A 50 Hz nanosecond pulsed laser is used to write the holographic pixels 5 . Multicoloured holographic 3D images are produced by using angular multiplexing, and the full parallax display employs spatial multiplexing. 3D telepresence is demonstrated by taking multiple images from one location and transmitting the information via Ethernet to another location where the hologram is printed with the quasi-real-time dynamic 3D display. Further improvements could bring applications in telemedicine, prototyping, advertising, updatable 3D maps and entertainment.

Design and fabrication of new infrared (IR) nonlinear optical (NLO) materials with balanced properties are urgently needed since commercial chalcopyrite‐like (CL) NLO crystals are suffering from their intrinsic drawbacks. Herein, the first defect‐CL (DCL) alkali‐earth metal (AEM) selenide IR NLO material, DCL‐MgGa2Se4, has been rationally designed and fabricated by a structure prediction and experiment combined strategy. The introduction of AEM tetrahedral unit MgSe4 effectively widens the band gap of DCL compounds. The title compound exhibits a wide band gap of 2.96 eV, resulting in a high laser induced damage threshold (LIDT) of ≈3.0 × AgGaS2 (AGS). Furthermore, the compound shows a suitable second harmonic generation (SHG) response (≈0.9 × AGS) with a type‐I phase‐matching (PM) behavior and a wide IR transparent range. The results indicate that DCL‐MgGa2Se4 is a promising mid‐to‐far IR NLO material and give some insights into the design of new CL compound with outstanding IR NLO properties based on the AEM tetrahedra and the structure predication and experiment combined strategy. The first defect‐chalcopyrite‐like alkali‐earth metal selenide IR NLO material DCL‐MgGa2Se4 with balanced SHG response and band gap is rationally designed and fabricated by a calculation and experiment combined strategy.

Carbon nanotubes possess unique properties that make them potentially useful in many applications in optoelectronics. This review describes the fundamental optical behaviour of carbon nanotubes as well as their opportunities for light generation and detection, and photovoltaic energy generation. Carbon nanotubes (CNTs) are nearly ideal one-dimensional (1D) systems, with diameters of only 1–3 nm and lengths that can be on the scale of centimetres. Depending on the arrangement of the carbon-atom honeycomb structure with respect to their axis, CNTs can be direct bandgap semiconductors, or metals with nearly ballistic conduction. The excited states of semiconducting CNTs can be produced by either optical or electrical means and form strongly bound (with dissociation energies of around 0.5 eV), luminescent, 1D excitons. The single-atomic-layer structure makes the optical properties of CNTs especially sensitive to their environment and external fields, and this can be used to tune them. Here we review the nature and properties of CNT excited states, the optical and electrical mechanisms of their production, their radiative and non-radiative modes of decay, the role of external electric fields, and their possible technological use as nanometre-scale light sources, photodetectors and photovoltaic devices.

Q-switched lasers have occupied important roles in industrial applications such as laser marking, engraving, welding, and cutting due to their advantages in high pulse energy. Here, SnS2-based Q-switched lasers are implemented. Consid-ering that SnS2 inherits the thickness sensitive optical characteristics of TMD, three kinds of SnS2 with different thick-ness are characterized in terms of nonlinearity and used to realize the Q-switched pulses under consistent implementa-tion conditions for comparison tests. According to the results, the influence of thickness variation on the nonlinear per-formance of saturable absorber, such as modulation depth and absorption intensity, and the influence on the correspond-ing laser are analyzed. In addition, compared with other traditional saturable absorbers, the advantage of SnS2 in realiz-ing ultrashort pulses is also noticed. Our work explores the thickness-dependent nonlinear optical properties of SnS2, and the rules found is of great reference value for the establishment of target lasers.

The structural alteration with π-linkers was used to design a donor–acceptor type series of 2,2′-(pyrimidine-4,6-diyl)bis(2,3-dihydro-1,3-benzothiazole) ( PB )-based chromophores ( AH1 – AH7 ) to exploit the adjustments in their optical characteristics. To investigate the electronic geometries, absorption wavelengths, charge transfer processes, and the effect of structural alterations on nonlinear optical (NLO) characteristics, density functional theory (DFT) simulations have been used. During the UV–visible study, several long-range and range separated functionals like B3LYP, CAM-B3LYP, B97XD, and APFD with the 6-311G + (d,p) basis set were used to select the efficient level at DFT. As a response, UV–vis data indicated an intriguing consistency at the B3LYP level across experimental and TD-DFT-based values of PB . All the designed molecules had a smaller energy band gap (0.84–3.67 eV) and wide absorption spectra inside the visible region. Natural bond orbital (NBO) results indicated a significant push–pull operation, with donors and π-conjugates exhibiting positive values and most acceptors exhibiting the minimum values. Electronic transformations between electron donors to acceptor moiety, Trifluoromethyl ( TFM ) via π-conjugated linkers were shown to have a superior linear ˂ α  >  and nonlinear ( β total ) NLO values of 306–474 and 40–230 Debye-Angstrom −1 respectively. When chromophores with one phenyl π-linker were compared to those with the two π-linkers, the chromophores with the higher π-linker showed increased hyperpolarizability. The highest second-order hyperpolarizability ( β) was found to be 230.11 Debye-Angstrom −1 which was about five times higher than urea (standard). This research has shown that by manipulating the kind of π-spacers, novel metal-free NLO compounds may be created, which might be used for high-tech NLO purposes.

The two-dimensional (2D) layered material MoS has attracted numerous attentions for electronics and optoelectronics applications. In this work, a novel type of MoS -doped sol-gel glass composite material is prepared. The nonlinear optical properties of prepared MoS /SiO composite material are measured with modulation depth (ΔT) of 3.5% and saturable intensity (I ) of 20.15 MW/cm . The optical damage threshold is 3.46 J/cm . Using the MoS /SiO composite material as saturable absorber (SA), a passive mode-locked Er-doped fiber (EDF) laser is realized. Stable conventional soliton mode-locking pulses are successfully generated with a pulse width of 780 fs at the pump power of 90 mW. In the pump power range of 100-600 mW, another stable mode-locking operation is obtained. The pulse width is 1.21 ps and the maximum output power is 5.11 mW. The results indicate that MoS /SiO composite materials could offer a new way for optical applications.