Nanophotonics

Bright single photon emission from a quantum dot in a circular Bragg grating microcavity

by Serkan Ates

Submitted for publication

Bright single photon emission from single quantum dots in suspended circular Bragg grating microcavities is... more Bright single photon emission from single quantum dots in suspended circular Bragg grating microcavities is demonstrated. This geometry has been designed to achieve efficient (> 50 %) single photon extraction into a near-Gaussian shaped far-field pattern, modest (~10x) Purcell enhancement of the radiative rate, and a spectral bandwidth of a few nanometers. Measurements of fabricated devices show progress towards these goals, with collection efficiencies as high as ~10% demonstrated with moderate spectral bandwidth and rate enhancement. Photon correlation measurements are performed under above-bandgap excitation (pump wavelength = 780 nm to 820 nm) and confirm the single photon character of the collected emission. While the measured sources are all antibunched and dominantly composed of single photons, the multi-photon probability varies significantly. Devices exhibiting tradeoffs between collection efficiency, Purcell enhancement, and multi-photon probability are explored and the results are interpreted with the help of finite-difference time-domain simulations. Below-bandgap excitation resonant with higher states of the quantum dot and/or cavity (pump wavelength = 860 nm to 900 nm) shows a near-complete suppression of multi-photon events and may circumvent some of the aforementioned tradeoffs.

Background-free quantum frequency conversion of single photons from a semiconductor quantum dot

by Serkan Ates

Submitter for publication

We demonstrate background-free quantum frequency conversion of single photons from an epitaxially-grown InAs quantum... more We demonstrate background-free quantum frequency conversion of single photons from an epitaxially-grown InAs quantum dot. Single photons at ~ 980 nm are combined with a pump laser near 1550 nm inside a periodically-poled lithium niobate (PPLN) waveguide, generating single photons at ~ 600 nm. The large red-detuning between the pump and signal wavelengths ensures nearly background-free conversion, avoiding processes such as upconversion of anti-Stokes Raman scattered pump photons in the PPLN crystal. Second-order correlation measurements on the single photon stream are performed both before and after conversion, confirming the preservation of photon statistics during the frequency conversion process.

Analytical properties of the plasmon decay profile in a periodic metal-nanoparticle chain

by Kin Hung Fung

Application of Plasmonic Bowtie Nanoantenna Arrays for Optical Trapping, Stacking, and Sorting

by Kin Hung Fung

Ultra-broadband Light Absorption by a Sawtooth Anisotropic Metamaterial Slab

by Kin Hung Fung

Book Review: Nanoscience Education, Workforce Training, and K-12 Resources

by Alex Broudy

Published in the Journal of Nanophotonics. Co-authored with:

Richard Doyle, Reviewer, Pennsylvania State University, Department of Science, Technology and Society, Nanofutures Working Group, University Park, Pennsylvania 16802, USA, mobius@psu.edu; Alex Broudy, Pennsylvania State University, Department of Spanish, Italian and Portuguese, Nanofutures Working Group, University Park, Pennsylvania, 16802, USA, azc5018@psu.edu; and David Saint John, Department of Materials Science and Engineering, Nanofutures Working Group, University Park, Pennsylvania 16802, USA, dbs198@psu.edu.

"Just in time for teachers, students, parents, and researchers,
Nanoscience Education, Workforce Training,... more "Just in time for teachers, students, parents, and researchers,
Nanoscience Education, Workforce Training, and K-12 Resources offers a comprehensive and wide-ranging toolkit for
integrating the transformative effects of nanotechnology into
our schools and lives. There’s a stack of books on our desk
and a cloud of PDFs on our desktop that focus on the social
and ethical implications (SEI) of nanotech, but this 2011 collection by Judith Light Feather and Migeul F. Aznar will be
among the few “go to” texts for our classes and research in
coming years. With critical essays, lively pedagogical ideas
and techniques, and a veritable database of resources that
more than deliver on the title keyword, the book is a timely
tool for growing the best of all plausible nanotechnological
futures."

Titanium nitride as a plasmonic material for visible wavelengths

by Gururaj Naik

Searching for better plasmonic materials

by Gururaj Naik

Nanoimprint fabrication of gold nanocones with~ 10 nm tips for enhanced optical interactions

by Janne Simonen

Arrays of metallic nanocones fabricated by UV-nanoimprint lithography

by Janne Simonen

Broadband infrared mirror using guided-mode resonance in a subwavelength germanium grating

by Janne Simonen

Joseph S. T. Smalley, Yanhui Zhao, Ahmad Ahasan Nawaz, Qingzhen Hao, Yi Ma, Iam-Choon Khoo, and Tony Jun Huang, High Contrast Modulation of Plasmonic Signals Using Nanoscale Dual-Frequency Liquid Crystals, Optics Express, Vol. 19, 16, 15265-15274, 2011

by Joseph Smalley

Designing Quantum Memories With Embedded Control: Photonic Circuits for Autonomous Quantum Error Correction

by Hendra Nurdin

Co-authored with J. Kerckhoff, D. S. Pavlichin and H. Mabuchi

We propose an approach to quantum error correction based on coding and continuous syndrome readout via scattering of... more We propose an approach to quantum error correction based on coding and continuous syndrome readout via scattering of coherent probe fields, in which the usual steps of measurement and discrete restoration are replaced by direct physical processing of the probe beams and coherent feedback to the register qubits. Our approach is well matched to physical implementations that feature solid-state qubits embedded in planar electromagnetic circuits, providing an autonomous and ‘‘on-chip’’ quantum memory design requiring no external clocking or control logic.

Observation of Non-Markovian Dynamics of a Single Quantum Dot in a Micropillar Cavity

by Serkan Ates

Phys. Rev. Lett. 106, 233601 (2011)

We measure the detuning-dependent dynamics of a quasiresonantly excited single quantum dot coupled to a micropillar... more We measure the detuning-dependent dynamics of a quasiresonantly excited single quantum dot coupled to a micropillar cavity. The system is modeled with the dissipative Jaynes-Cummings model where all experimental parameters are determined by explicit measurements. We observe non-Markovian dynamics when the quantum dot is tuned into resonance with the cavity leading to a nonexponential decay in time. Excellent agreement between experiment and theory is observed with no free parameters providing the first quantitative description of an all-solid-state cavity QED system based on quantum dot emitters.

Dephasing of Triplet-Sideband Optical Emission of a Resonantly Driven InAs/GaAs Quantum Dot inside a Microcavity

by Serkan Ates

Phys. Rev. Lett. 106, 247402 (2011)

Detailed properties of resonance fluorescence from a single quantum dot in a micropillar cavity are investigated, with... more Detailed properties of resonance fluorescence from a single quantum dot in a micropillar cavity are investigated, with particular focus on emission coherence in the dependence on optical driving field power and detuning. A power-dependent series over a wide range reveals characteristic Mollow triplet spectra with large Rabi splittings of |Ω|≤15  GHz. In particular, the effect of dephasing in terms of systematic spectral broadening ∝Ω2 of the Mollow sidebands is observed as a strong fingerprint of excitation-induced dephasing. Our results are in excellent agreement with predictions of a recently presented model on phonon-dressed quantum dot Mollow triplet emission in the cavity-QED regime.

Controlling the Directional Emission of Light by Periodic Arrays of Heterostructured Semiconductor Nanowires

by Olaf Janssen

S.L. Diedenhofen, O.T.A. Janssen, M. Hocevar, A. Pierret, E.P A.M. Bakkers, H.P. Urbach, and J. Gomez Rivas

We demonstrate experimentally the directional emission of light by InAsP segments embedded in InP nanowires. The... more We demonstrate experimentally the directional emission of light by InAsP segments embedded in InP nanowires. The nanowires are arranged in a periodic array, forming a 2D photonic crystal slab. The directionality of the emission is interpreted in terms of the preferential decay of the photoexcited nanowires and the InAsP segments into Bloch modes of the periodic structure. By simulating the emission of arrays of nanowires with the emitting segments located at different heights, we conclude that the position of this active region strongly influences the directionality and efficiency of the emission. Our results will help to improve the design of nanowire based LEDs and single photon sources.

Si nanoparticle-Er3+ coupling through contact in as-deposited nanostructured films

by Sara Núñez-Sánchez

Published in Applied Physics Letters. Authors: S. Núñez-Sánchez, P. M. Roque, R. Serna, and A. K. Petford-Long

The efficient excitation of Er3+ ions through contact with Si nanoparticles (NPs) is demonstrated. A nanostructured... more The efficient excitation of Er3+ ions through contact with Si nanoparticles (NPs) is demonstrated. A nanostructured doping process has been developed that leads to contact between Si NPs formed in situ and optically-active Er3+ ions embedded in Al2O3. This is achieved by independent and consecutive deposition of the dopants and matrix. The Si NP–Er3+ contact regime enhances the probability of efficient interaction due to the local spatial overlap of the electronic states of the Er3+ and of the Si NP exciton, enabling energy transfer by interband exciton recombination. This leads to up to 53% of the Er3+ ions being excited in as-deposited films.

Single Molecular Stamping of a Sub-10-Nm Colloidal Quantum Dot Array

by Ashwini Gopal

Strong Geometrical Dependence of the Absorption of Light in Arrays of Semiconductor Nanowires

by Olaf Janssen

S.L. Diedenhofen; O.T.A. Janssen; G. Grzela; E.P.A.M. Bakkers; J. Gomez Rivas

ACS Nano (2011)

We demonstrate experimentally that arrays of base-tapered InP nanowires on top of an InP substrate form a broad band... more We demonstrate experimentally that arrays of base-tapered InP nanowires on top of an InP substrate form a broad band and omnidirectional absorbing medium. These characteristics are due to the specific geometry of the nanowires. Almost perfect absorption of light (higher than 97%) occurs in the system. We describe the strong optical absorption by finite-difference time-domain simulations and present the first study of the influence of the geometry of the nanowires on the enhancement of the optical absorption by arrays. Cylindrical nanowires present the highest absorption normalized to the volume fraction of the semiconductor. The absolute absorption in layers of conical nanowires is higher than that in cylindrical nanowires but requires a larger volume fraction of semiconducting material. Base-tapered nanowires, with a cylindrical top and a conical base, represent an intermediate geometry. These results set the basis for an optimized optical design of nanowire solar cells.

Rigorous simulations of emitting and non-emitting nano-optical structures

by Olaf Janssen

PhD Thesis; O.T.A. Janssen

Delft University of Technology, November (2010)

In the next decade, several applications of nanotechnology will change our lives. LED lighting is about to replace the... more In the next decade, several applications of nanotechnology will change our lives. LED lighting is about to replace the common light bulb. The main advantages are its energy efficiency and long lifetime. LEDs can be much more efficient, when part of the emitted light that is currently trapped in the device, could be radiated out of the device. Other devices such as photovoltaic solar cells and biosensors can also be made more efficient and cheaper.

LEDs, solar cells and biosensors have in common that they consist of small structures of the order of the wavelength of the light. With such small structures light can be manipulated in a special way. In this thesis, we describe a method to calculate the interaction of light with these small structures. It is shown that an efficient LED which radiates light, can be treated as a solar cell that absorbs as much of the incoming light as possible. On this so-called reciprocity principle, which was discovered by Henrik Antoon Lorentz, a very efficient computational optimalisation method can be based. With this method existing designs of for example LEDs can be made more efficient iteratively. This thesis shows optimized designs of LEDs, solar cells and biosensors.