Applied optics articles within Nature Communications

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  • Article |

    Finding broadband terahertz emitters and detectors is key to developing practical terahertz technologies and to exploring fundamental nonlinear optics. Luo et al.show that split-ring-resonator metamaterials of a few tens of nanometres thickness can efficiently generate terahertz pulses up to 4 THz.

    • Liang Luo
    • , Ioannis Chatzakis
    •  & Costas M. Soukoulis
  • Article |

    Extending the optical response of silicon below the band gap towards infrared wavelengths is of interest for applications such as imaging. Here, Mailoa et al. achieve room-temperature infrared photoresponse from silicon doped with supersaturated concentrations of gold impurities.

    • Jonathan P. Mailoa
    • , Austin J. Akey
    •  & Tonio Buonassisi
  • Article
    | Open Access

    To use colloidal quantum dots in applications such as p-n junction solar cells, doping of the quantum dots is needed. Here, Stavrinadis et al. achieve lead sulphide quantum dot p-n homojunctions by heterovalent cation substitution of lead using bismuth.

    • Alexandros Stavrinadis
    • , Arup K. Rath
    •  & Gerasimos Konstantatos
  • Article |

    To study the dynamics of materials and biological samples at ultrafast time scales it is beneficial to use two short laser pulses, ideally at different energies. Here, the authors demonstrate the generation of two femtosecond hard X-ray laser pulses in a free electron laser, with more than 30% energy separation.

    • Toru Hara
    • , Yuichi Inubushi
    •  & Tetsuya Ishikawa
  • Article
    | Open Access

    The rectangular spectral shape of sinc Nyquist pulses are ideal for data transmission as they make optimal use of the available frequency spectrum. Here Soto et al.develop a scheme for the optical generation of sinc-shaped Nyquist pulses with very high quality, based on the direct synthesis of rectangular, phase-locked frequency combs.

    • Marcelo A. Soto
    • , Mehdi Alem
    •  & Thomas Schneider
  • Article
    | Open Access

    Practical implementations of quantum communication need to securely deliver information over long distances without line-of-sight. Towards this goal, Cuevas et al.use an actively stabilized interferometer to close the geometry loophole for a Bell inequality violation over 1 km of optical fibre.

    • A. Cuevas
    • , G. Carvacho
    •  & G.B. Xavier
  • Article
    | Open Access

    The origin of the abnormal photovoltaic effect in bismuth ferrite thin films, which causes voltages larger than the band gap, is poorly understood. Bhatnagar et al.show that this effect can be attributed to a bulk photovoltaic effect and that it can be enhanced by controlling domain wall conductivity.

    • Akash Bhatnagar
    • , Ayan Roy Chaudhuri
    •  & Marin Alexe
  • Article
    | Open Access

    Photonic circuits are a promising route to developing scalable quantum technologies, if all the necessary components can be built. Using coupled resonator optical waveguides, Takesue et al.present an on-chip single-photon buffer that can delay one photon from a pair for 150 ps while preserving entanglement.

    • Hiroki Takesue
    • , Nobuyuki Matsuda
    •  & Masaya Notomi
  • Article |

    Future quantum technologies will require interfaces between photons transmitting information and solid-state devices storing and manipulating it. Towards this aim, Gao et al.show the transfer of information from a single photon to a semiconductor quantum dot through quantum teleportation protocols.

    • W.B. Gao
    • , P. Fallahi
    •  & A. Imamoğlu
  • Article
    | Open Access

    Although many electromagnetic cloaking schemes exist at different wavelengths, realizing a broadband visible wavelength device is hard. By relaxing the need for phase preservation inherent to most methods, Chen et al.present a ray-optics scheme for cloaking large-scale objects from the human eye.

    • Hongsheng Chen
    • , Bin Zheng
    •  & Baile Zhang
  • Article
    | Open Access

    Photonic quantum technologies will require efficient single-photon sources and spatial multiplexing has been explored as a route to achieve this. Here, the authors present a scheme to integrate several single-photon sources using spatial multiplexing for on-chip applications at telecommunications wavelengths.

    • M.J. Collins
    • , C. Xiong
    •  & B.J. Eggleton
  • Article |

    Controlling the propagation of microwaves in air is hard because of their divergence and the lack of suitable optics. Kudyshev et al. show how this can be overcome using plasma channels to create virtual hyperbolic metamaterials to collimate and guide radar beams.

    • Zhaxylyk A. Kudyshev
    • , Martin C. Richardson
    •  & Natalia M. Litchinitser
  • Article
    | Open Access

    Optical reference cavities are important in precision time keeping and low-noise microwave generation. Here as a step towards their miniaturization, the authors demonstrate a chip-based reference cavity that uses a spiral geometry to improve stability by introducing thermal and mechanical immunity.

    • Hansuek Lee
    • , Myoung-Gyun Suh
    •  & Kerry J. Vahala
  • Article |

    In microscopy, the standard quantum limit represents the best achievable signal-to-noise ratio for a given light intensity. Here, the authors build an optical microscope that uses entanglement between photon pairs to overcome this barrier.

    • Takafumi Ono
    • , Ryo Okamoto
    •  & Shigeki Takeuchi
  • Article |

    Nonlinear interactions of single photons are important for future quantum technologies, but they are weak and hard to detect. By performing sum-frequency generation between single photons and single-photon level coherent states, Guerreiro et al. show that high-efficiency waveguides can overcome this.

    • T. Guerreiro
    • , E. Pomarico
    •  & N. Gisin
  • Article |

    Flexible CdTe solar cells on metal foil substrates are promising for low-cost roll-to-roll fabrication, but their efficiency is usually low because of their inverted structure. By controlling the doping of the CdTe layer with copper, Kranz et al. show that efficiencies up to 13.6% can be obtained.

    • Lukas Kranz
    • , Christina Gretener
    •  & Ayodhya N. Tiwari
  • Article |

    Customizing the output from a laser is typically done by appropriate optical elements. Here Ngcobo et al.show that a digitally controlled holographic mirror placed within the laser cavity can be used to dynamically select the desired laser output modes.

    • Sandile Ngcobo
    • , Igor Litvin
    •  & Andrew Forbes
  • Article
    | Open Access

    Electrically insulating ligands and doping of colloidal semiconductor nanocrystals continue to be significant challenges for practical nanocrystal-based optoelectronics. Wheeler et al.demonstrate a new surface chemistry technique that confronts both of these challenges simultaneously.

    • Lance M. Wheeler
    • , Nathan R. Neale
    •  & Uwe R. Kortshagen
  • Article
    | Open Access

    Near-field effects generated by nanoantennas provide insights into light–matter interactions and new ways of sensing at low concentrations. By measuring characteristic vibrations from molecular patches, Dregely et al.are able to characterize the field intensity of buried three-dimensional nanostructures.

    • Daniel Dregely
    • , Frank Neubrech
    •  & Harald Giessen
  • Article
    | Open Access

    Phonon lasers are the acoustic equivalent to optical lasers. Here Maryam and colleagues study the dynamics of semiconductor phonon lasers operating in the terahertz frequency regime, and show that these dynamics are similar to that of comparable optical lasers.

    • W. Maryam
    • , A. V. Akimov
    •  & A. J. Kent
  • Article
    | Open Access

    Finding ways to accumulate electronic spins of a given polarization in a given location is important to the development of spintronics. Endres et al.demonstrate a device that uses light to drive the accumulation of spin using a similar principle that a solar cell uses to drive the accumulation of charge.

    • B. Endres
    • , M. Ciorga
    •  & C.H. Back
  • Article
    | Open Access

    Microwaves are of interest for applications such as communications, radar and metrology. Here, Li et al. demonstrate an on-chip microresonator device for the generation of microwaves by optical means, instead of the usual electronic devices.

    • Jiang Li
    • , Hansuek Lee
    •  & Kerry J. Vahala
  • Article |

    Compact, tunable terahertz sources are highly desired for sensing and imaging applications. Here Vijayraghavan et al. demonstrate room-temperature quantum cascade laser sources based on the non-linear optical conversion of mid-infrared light that provide a tunable output over a 3.5-THz bandwidth.

    • Karun Vijayraghavan
    • , Yifan Jiang
    •  & Mikhail A. Belkin
  • Article
    | Open Access

    Ferroelectric RAM is considered a promising candidate on the quest for a universal memory, but the concept is still problem prone. Here, the authors use the ferroelectric photovoltaic effect as a non-destructive read-out method for a new prototype memory, which shows good data retention and fatigue resistance.

    • Rui Guo
    • , Lu You
    •  & Junling Wang
  • Article |

    Polymer light-emitting diodes promise cheap and flexible lighting and displays, but their fabrication is hindered by high-vacuum methods for creating cathodes. Zheng et al.show an all-solution processing approach to polymer diodes that removes this obstacle, offering roll-to-roll fabrication of devices.

    • Hua Zheng
    • , Yina Zheng
    •  & Yong Cao
  • Article |

    Lenses are well-understood optical instruments to focus light. The flame lens realized here by Michaelis et al. offers light focusing with a damage threshold several orders of magnitude higher than that of most conventional lenses.

    • Max M. Michaelis
    • , Cosmas Mafusire
    •  & Andrew Forbes
  • Article |

    Graphene holds great potential for use in photodetectors, owing to its ability to absorb light over a wide range of wavelengths. Here Zhang et al. report a large photoresponsivity of 8.6 AW-1 over a broad wavelength range in pure monolayer graphene.

    • By Yongzhe Zhang
    • , Tao Liu
    •  & Qi Jie Wang
  • Article |

    Exciton-polaritons—coupled states of excitons and photons—exhibit interesting properties that may make them suitable as information carriers for optical computing technologies. With this goal in mind, Ballarini et al. demonstrate an all-optical polariton transistor that also operates as a logic gate.

    • D. Ballarini
    • , M. De Giorgi
    •  & D. Sanvitto
  • Article |

    Solitons are waves, occurring in systems such as water channels and optical fibres that preserve their shape as they travel. Here the observation of solitons in multimode optical fibres offers a platform for studying spatiotemporal wave packets, and could allow high peak power transmission along with increased data rates in low-cost telecommunications.

    • W. H. Renninger
    •  & F. W. Wise
  • Article |

    The control of thermal radiation is important for applications such as energy conversion and radiative cooling. Here Fan et al. demonstrate a thermal extraction scheme that can enhance the emission of a finite-sized blackbody-like emitter.

    • Zongfu Yu
    • , Nicholas P. Sergeant
    •  & Shanhui Fan
  • Article |

    Free-electron lasers offer exciting new possibilities for X-ray studies on ultrafast timescales, but their shot-to-shot variability requires new diagnostic tools. Using a plasma switch cross-correlator, Riedel et al. present a single-shot online diagnostic to retrieve the duration of extreme ultraviolet pulses.

    • R. Riedel
    • , A. Al-Shemmary
    •  & F. Tavella
  • Article |

    Ptychographic methods can retrieve the complex sample transmittance from diffraction patterns that may have a large dynamic range. For soft X-ray spectromicroscopy, Maiden et al. use a diffuser to randomize the probe phase, reducing the dynamic range of the diffraction data by an order of magnitude.

    • A.M. Maiden
    • , G.R. Morrison
    •  & J.M. Rodenburg
  • Article |

    The strong electro-optical response of BaTiO3 could be useful for making high-speed switches for optical telecommunications. Abel et al. demonstrate the ability to maintain this response in BaTiO3films grown directly onto silicon, extending its potential to the development of silicon photonics.

    • Stefan Abel
    • , Thilo Stöferle
    •  & Jean Fompeyrine
  • Article |

    Plasmons excited in gratings create strong resonant absorptions that depend on the nanostructure period. By patterning a gold grating on a silicon substrate, Sobhani et al. exploit plasmon-induced hot electron photocurrent generation to create a narrowband infrared photodetector with greatly enhanced absorption efficiency.

    • Ali Sobhani
    • , Mark W. Knight
    •  & Naomi J. Halas
  • Article
    | Open Access

    The Faraday effect rotates the polarization plane of light in magneto-optical materials and is used for optical isolators blocking unwanted backscattering of light. Usually a small effect, Chin et al. have observed a large enhancement of the optical rotation by magneto-plasmonics.

    • Jessie Yao Chin
    • , Tobias Steinle
    •  & Harald Giessen
  • Article |

    By having the electrons and lattice at high temperature, photon-enhanced thermionic emission offers improved electron extraction energy in solar conversion devices. Schwede et al.use a heterostructure design to introduce an internal interface, showing higher quantum efficiencies than previous experiments.

    • J.W. Schwede
    • , T. Sarmiento
    •  & Z.-X. Shen
  • Article |

    Controlling the interaction between distant quantum dots is important if they are to be used in quantum information devices. Delbecq et al. place two quantum dot circuits in a microwave cavity and show that they interact via cavity photons, even though they are separated by 200 times their own size.

    • M.R. Delbecq
    • , L.E. Bruhat
    •  & T. Kontos