S. Tomljenovic-Hanic

• PhD ANU
• University of Melbourne

Fluorescence-based techniques have great potential in the field of bioimaging and could bring tremendous progress in microbiology and biomedicine. The most essential element in these techniques is fluorescent nanomaterials. The use of fluorescent nanoparticles as contrast agents for bioimaging is a large topic to cover. The purpose of this mini-rev...

Nanotechnology has engraved new insight into the material sciences and zinc oxide nanomaterials (ZnO NMs) are one of the most extensively used material in healthcare and environmental remediation applications attributable to their biodegradability and tunable physical and chemical properties. This review concentrates on three aspects of the product...

Fluorescent nanoparticles (NPs) have been increasingly studied as contrast agents for better understanding of biological processes at the cellular and molecular level. However, their use as bioimaging tools is strongly dependent on their optical emission as well as their biocompatibility. This work reports the fabrication and characterization of si...

Nematode eggs are pervasive pathogens that infect billions of people and livestock every year. Adult parasitic nematode worms can be distinguished based on their size and morphology. However, their eggs, particularly their species Ascaris lumbricoides and Ascaris suum cannot be identified from each other. Identifying eggs of helminths from wastewat...

Nitrogen-doped ultrananocrystalline diamond (N-UNCD) is a promising material for a variety of neural interfacing applications, due to its unique combination of high conductivity, bioinertness, and durability. One emerging application for N-UNCD is as a photoelectrode material for high-precision optical neural stimulation. This may be used for the t...

Imaging of biological matter by using fluorescent nanoparticles (NPs) is becoming a widespread method for in vitro imaging. However, currently there is no fluorescent NP that satisfies all necessary criteria for short-term in vivo imaging: biocompatibility, biodegradability, photostability, suitable wavelengths of absorbance and fluorescence that d...

Nanocellulose has emerged as a promising material for many biomedical applications. Depending on the source of the nanocellulose and the chemical treatment, the resulting optical properties can vary significantly. In particular, autofluorescence can exist in various wavelength ranges. Except for chlorophyll related autofluorescence, all other studi...

Nitrogen-doped ultrananocrystalline diamond (N-UNCD) is a promising material for a variety of neural interfacing applications, due to its unique combination of high conductivity, bioinertness, and durability. One emerging application for N-UNCD is as a photoelectrode material for high-precision optical neural stimulation. This may be used for the t...

Fluorescence properties of crystallographic point defects within different morphologies of titanium dioxide were investigated. For the first time, room-temperature single-photon emission in titanium dioxide optical defects was discovered in thin films and commercial nanoparticles. Three-level defects were identified because the g (2) correlation da...

Titanium dioxide is an emerging optical material, with a relatively high refractive index (n ∼ 2), which allows for high confinement of the electromagnetic field. Extensive research has been conducted on the negatively charged nitrogen vacancy centre in diamond due to its robust electronic and optical properties. In particular, its stable room-temp...

Zinc oxide (ZnO) is a promising semiconductor that is suitable for bioimaging applications due to its intrinsic defect fluorescence. However, ZnO generally suffers from poor photostability. We report room-temperature single-photon emission from optical defects found in ZnO nanoparticles (NPs) formed by ion implantation followed by thermal oxidation...

High quality, ultra-thin single crystal diamond (SCD) membranes that have a thickness in the sub-micron range are of extreme importance as a materials platform for photonics, quantum sensing, nano/micro electro-mechanical systems (N/MEMS) and other diverse applications. However, the scalable fabrication of such thin SCD membranes is a challenging p...

Nanoparticles hold great potential in contributing to high-resolution bioimaging as well as for biomedical applications. Although, selenium (Se) nanoparticles (NPs) have been investigated owing to their potential roles in therapeutics, the imaging capability of these NPs has never been explored. This manuscript identifies the intrinsic fluorescence...

Nanoparticle (NP) based technologies have proved to be considerably beneficial for advances in biomedicine especially in the areas of disease detection, drug delivery and bioimaging. Over the last few decades, NPs have garnered interest for their exemplary impacts on the detection, treatment, and prevention of cancer. The full potential of these te...

High resolution bioimaging is not only critical to the study of cellular structures and processes but it also has important applications in drug delivery and therapeutics. Fluorescent nanodiamonds (NDs) are excellent candidates for long-term bioimaging and tracking of biological structures at the nanoscale. Encapsulating NDs in natural biopolymers...

The negatively charged nitrogen-vacancy colour center (NV(-) center) in nanodiamond is an excellent single photon source due to its stable photon generation in ambient conditions, optically addressable nuclear spin state, high quantum yield and its availability in nanometer sized crystals. In order to make practical devices using nanodiamond, highl...

The negatively-charged nitrogen vacancy (NV(-)) center in diamond is of great interest for quantum information processing and quantum key distribution applications due to its highly desirable long coherence times at room temperature. One of the challenges for their use in these applications involves the requirement to further optimize the lifetime...

The emission rate of a radiating dipole within a nanoparticle is crucially dependent on its surrounding refractive index environment. In this manuscript, we present numerical results on how the emission rates are affected for nanoparticles in a homogenous and substrate environment. These results are general, applicable to any refractive index distr...

The pixel size imposes a fundamental limit on the amount of information that can be displayed or recorded on a sensor. Thus, there is strong motivation to reduce the pixel size down to the nanometre scale. Nanometre colour pixels cannot be fabricated by simply downscaling current pixels due to colour cross talk and diffraction caused by dyes or pig...

We propose a high-Q photonic crystal cavity formed by introducing random disorder to the central region of an otherwise defect-free photonic crystal slab (PhC). Three-dimensional finite-difference time-domain simulations determine the frequency, quality factor, Q, and modal volume, V, of the localized modes formed by the disorder. Relatively large...

We demonstrate a robust templated approach to pattern thin films of chemical vapor deposited nanocrystalline diamond grown from monodispersed nanodiamond (mdND) seeds. The method works on a range of substrates, and we herein demonstrate the method using silicon, aluminum nitride (AlN), and sapphire substrates. Patterns are defined using photo- and...

A new hybrid material consisting of nanodiamonds (NDs) and silk has been synthesized and investigated. NDs can contain bright fluorescence centers, important for bioprobes to image biological structures at the nanoscale and silk provides a transparent, robust matrix for these nanoparticles in-vivo or in-vitro. The ND-silk hybrid films were determin...

Fluorescent nanoparticles (NPs) have become versatile tools in a wide range of applications, from industrial to bio-medical applications. For some of them it is essential to detect and track such fluorescent NPs without additional tags. In this paper we present two examples of combining these NPs with optical materials: silken nanodiamonds and zinc...

We demonstrate activation of bright diamond single photon emitters in the near infrared range by thermal annealing alone, i.e., without ion implantation. The activation is crucially dependent on the annealing ambient. The activation of the single photon emitters is only observed when the sample is annealed in forming gas (4% H2 in Ar) above tempera...

In this paper we present two examples of combining fluorescent nanoparticles with photonic materials. First, we present the results on new compound: nanodiamonds and silk. Second, we report on ZnO fluorescence, with ZnO nanoparticles obtained by Zn-ion implantation in silica.

We report room temperature single photon emission from optical emitters in zinc oxide (ZnO) nanoparticles formed using ion implantation and thermal oxidation in a silica substrate.

We describe the current status in fabrication and characterization of diamond-based optical structures. First, we describe the unique properties of diamond and broadly consider three applications – sensing, single-photon generation for quantum key distribution, and scalable quantum information processing – that benefit from, or are enabled by diamo...

We propose a new approach for creating reconfigurable high-Q cavities in defect-free photonic crystal slabs (PCSs). The approach relies on selective air-hole infiltration in otherwise defect-free PCSs. We show that using this method we can design ultrahigh-Q microcavities, with Q˜10⁶. Numerical calculations indicate a large number of high-Q modes w...

We numerically demonstrate an optical waveguide structure for the coherent tunnelling adiabatic passage of photons. An alternative coupling scheme is used compared to earlier work. We show that a three rib optical waveguide structure is robust to material loss in the intermediate waveguide and variations to the waveguide parameters. We also present...

A method for engineering thin (<100 nm) layers of homoepitaxial diamond containing high quality, spectrally stable, isolated nitrogen-vacancy (NV) centres is reported. The photoluminescence excitation linewidth of the engineered NVs are as low as 140 MHz, at temperatures below 12 K, while the spin properties are at a level suitable for quantum memo...

We detail the passivation of ultra-high purity diamond and subsequent homoepitaxial growth of thin diamond layers containing spectrally stable nitrogen vacancy (NV) centres. We demonstrate a reduction of three orders of magnitude in the density of fluorescent NV centres in single crystal diamond due to hydrogen plasma treatment. This reduced fluore...

Diamond color centers are an important frontier for room-temperature solid-state quantum devices. Here we show incorporation of diamond nanoparticles into tellurite glass optical fibers, offering a platform for quantum sensing and single photons.

We study the effect of 30 keV gallium ion implantation on the optical properties of diamond, as determined using spectroscopic ellipsometry. We find that the refractive index of the implanted layer can be either lower, or higher, than that of pristine diamond, depending on the implantation dose. This observation provides a new route to optical devi...

We report electrical tuning by the Stark effect of the excited-state structure of single nitrogen-vacancy (NV) centers located less than or approximately equal to 100 nm from the diamond surface. The zero-phonon line (ZPL) emission frequency is controllably varied over a range of 300 GHz. Using high-resolution emission spectroscopy, we observe elec...

We show reduction in the emission from nitrogen-vacancy (NV) centers in single crystal diamond due to exposure to hydrogen plasmas ranging from 700 �degrees C to 1000 �degrees C. Significant fluorescence reduction was observed beneath the exposed surface to 80 micrometres depth after �10 min and did not recover after post-annealing in vacuum for 7...

Room temperature single-photon emission and quantum characterization is reported for isolated defects in zinc oxide. The defects are observed in thin films of both in-house synthesized and commercial zinc oxide nanoparticles. Emission spectra in the red and infrared, second-order photon correlation functions, lifetime measurements, and photon count...

Integrated diamond networks based on cavity-coupled spin impurities offer a promising platform for scalable quantum computing. A key ingredient for this technology involves heralding entanglement by interfering indistinguishable photons emitted by pairs of identical spin qubits. Here we demonstrate the required control over the internal level struc...

We demonstrate that a high-Q photonic crystal cavity can be induced by the presence of a nanodiamond (ND) on the air-hole side wall in an otherwise defect-free photonic crystal. The ND itself acts as the perturbation, increasing the average refractive index, necessary to define the cavity; therefore self-aligned with the cavity. Such cavities are p...

We report on optical measurements which assess the impact of processing plasmas on the density of Nitrogen-Vacancy centres in ultra-high purity diamond. In particular we look at the depletion of NV- before and after exposure to a hydrogen plasma using confocal microscopy.

We demonstrate single photon emission from nanodiamond containing isolated single nitrogen-vacancy quantum emitters, embedded within tellurite glass optical fibres. This hybrid diamond-glass material presents a platform for next generation quantum photonics applications.

Nitrogen-vacancy (NV) centers in diamond exhibit unique quantum properties. On page 2806, Matthew R. Henderson and co-workers describe integrated diamond nanocrystals containing NV centers with an optical medium, tellurite soft glass. The inside cover image shows an example of a confocal scan of an optical fiber drawn from this material, detecting...

Quantum mechanics has defi ned twentieth century technologyand quantum information science has been identifi ed as potentiallyone of the most disruptive technologies of the twentyfirst century. [ 1 ] A major challenge for the development of thisfi eld is the requirement to create a quantum-classical interfaceto effi ciently allow quantum informatio...

Diamond is emerging as an optical supermaterial, due to its wide transparency bandwidth, excellent thermooptic properties and most notably its stable, large dipole moment, room temperature, single photon emitting colour centres. In this paper we present recent progress in the characterization of non radiative and radiative decay in single impuritie...

A microfluidic double heterostructure cavity is created in a silicon planar photonic crystal waveguide by selective infiltration of liquid crystal. We explore the infiltration and evaporation dynamics of the liquid crystal using a Fabry-Perot model.

Optofluidics, the marriage of photonics and microfluidics, uses the inherent flexibility of confined fluids to reversibly tune photonic structures beyond traditional fabrication methods. Photonic crystals (PhCs) are well suited to optofluidic tuning; their periodic air-hole microstructure is a natural candidate for housing liquids. This microstruct...

We demonstrate that cavities with Q>;10⁶ can be designed in defect-free photonic crystals made of photosensitive material (chalcogenide). Both positive and negative refractive index change can result in high-Q cavities.

A microfluidic double heterostructure cavity is created in a silicon planar photonic crystal waveguide by selective infiltration of a liquid crystal. The spectral evolution of the cavity resonances probed by evanescent coupling reveals that the liquid crystal evaporates, even at room temperature, despite its relatively low vapor pressure of 5 × 10⁻...

We investigate the photosensitive and thermo-optic nonlinear properties of chalcogenide glass photonic crystal (PhC) cavities at telecommunications wavelengths. We observe a photosensitive refractive index change in AMTIR-1 (Ge33As12Se55) material in the near-infrared, which is enhanced by light localization in the PhC cavity and manifests in a per...

We demonstrate numerically that a cavity can be induced in a defect-free photonic crystal slab made of photosensitive material such as chalcogenide glass. A key advantage of the design is the possibility for complete post-processing in an otherwise defect-free structure, and the cavity can thus be formed anywhere in the photonic crystal. We demonst...

Diamond is a unique material, with a host of attributes that seem to favour is as a platform for solid-state optical approaches to quantum information processing. Amongst the many outstanding properties of diamond, the most important for these applications are that it posses the largest transparency window in the visible regime, has the highest the...

We use optofluidic infiltration to precisely and reversibly engineer the dispersion of a photonic crystal defect waveguide post-fabrication. The amount of fluid infiltrated into the photonic crystal microstructure strongly influences the waveguide dispersion.

We describe progress in the field of tuning, (re)configuration of Photonic crystal (PhC) based devices with a particular emphasis on our recent concepts and techniques that we have developed to tune and/or reconfigure the properties of photonic crystal nanocavities. We show how our hybrid approach based on photosensitive material and tapered silica...

Optofluidic devices exploit the characteristics of liquids to achieve a dynamic adaptation of their optical properties. The use of liquids allows for functionalities of optical elements to be created, reconfigured or tuned. We present an overview of our work on fluid-control of optical elements and highlight the benefits of an optofluidic approach,...

We present a principle for the temperature stabilization of photonic crystal (PhC) cavities based on optofluidics. We introduce an analytic method enabling a specific mode of a cavity to be made wavelength insensitive to changes in ambient temperature. Using this analysis, we experimentally demonstrate a PhC cavity with a quality factor of Q ≈ 15 0...

In this review, we discuss the progress and prospects offered by chalcogenide glass photonic crystals. We show that by making photonic crystals from a highly-nonlinear chalcogenide glass, we have the potential to integrate a variety of active devices into a photonic chip. We describe the testing of two-dimensional Ge33As12Se55 chalcogenide glass ph...

Optofluidic devices exploit the characteristics of liquids to achieve a dynamic adaptation of their optical properties. The use of liquids allows for functionalities of optical elements to be created, reconfigured or tuned. We present an overview of our work on fluid-control of optical elements and highlight the benefits of an optofluidic approach,...

We present results showing the formation and evolution of a photonic crystal cavity during writing by selective optical exposure in a photosensitive chalcogenide photonic crystal. Q-factors of up to 125,000 were obtained in these cavities. (C) 2010 Optical Society of America

We demonstrate a high-Q ( ∼ 125,000 ) photonic crystal (PhC) cavity formed using a postprocessing optical exposure technique where the refractive index of a photosensitive chalcogenide PhC is modified locally. The evolution of the cavity resonances was monitored in situ during writing using a tapered fiber evanescent coupling system, and the Q of 1...

Optical cavities provide a route to sensing through the shift of the optical resonant peak. However, effective sensing with optical cavities requires the optimization of the modal quality factor, Q, and the field overlap with the sample, f. For a photonic crystal slab (PCS) this figure of merit, M = fQ, involves two competing effects. The air modes...

We present the first demonstration of a high-Q (~60000) photonic crystal (PhC) cavity formed post-fabrication by locally modifying the refractive index of a PhC made of a photosensitive chalcogenide glass.

All-optical tuning of a quantum dot in a coupled cavity system Appl. Phys. Lett. 100, 231107 (2012) Photonic crystal tunable slow light device integrated with multi-heaters Appl. Phys. Lett. 100, 221110 (2012) Parametric optomechanical oscillations in two-dimensional slot-type high-Q photonic crystal cavities Appl. Phys. Lett. 100, 211908 (2012) Ph...

We design extremely flexible, ultrahigh-Q, diamond-based double-heterostructure photonic crystal slab cavities by modifying the refractive index of the diamond. The refractive index changes needed for ultrahigh-Q cavities with Q ~ 107, are well within what can be achieved (Deltan ~ 0.02). The Q is around 30 times larger than previously reported des...

We investigate the temperature sensitivity of silicon-based optofluidic photonic crystal double-heterostructure resonators. We systematically study the optical properties of these resonators as function of temperature, specifically demonstrating the potential for creating temperature-insensitive photonic crystal devices.

Effective sensing with photonic crystal cavities requires optimization of modal quality factor and field overlap. For several unrelated cavities, we find the quality factor dominates, so that dielectric modes are strongly favored over air modes.

We design extremely flexible ultrahigh- Q diamond-based double-heterostructure photonic crystal slab cavities by modifying the refractive index of the diamond. The refractive index changes needed for ultrahigh-Q cavities with Q ~ 10⁷, are well within what can be achieved (Δn ~ 0.02). The cavity modes have relatively small volumes V<2 (λ/n)³ , makin...

We report reconfigurable optofluidic photonic crystal components in silicon-based membranes by controllably infiltrating and removing fluid from holes of the photonic crystal lattice. Systematic characterizations of our fluidically defined microcavities are presented, corresponding with the capability to increase or decrease the span of the fluid-f...

We demonstrate postprocessed microfluidic double-heterostructure cavities in silicon-based photonic crystal slab waveguides. The cavity structure is realized by selective fluid infiltration of air holes using a glass microtip, resulting in a local change of the average refractive index of the photonic crystal. The microcavities are probed by evanes...

We demonstrate the spectral and spatial reconfigurability of photonic crystal double-heterostructure cavities in silicon by microfluidic infiltration of selected air holes. The lengths of the microfluidic cavities are changed by adjusting the region of infiltrated holes in steps of several microns. We systematically investigate the spectral signatu...

We demonstrate reconfigurable microfluidic photonic crystal components in silicon-based membranes by select hole infiltration. We employ a diverse range of fluids and show the capability of filling a single hole. Systematic characterisations of the induced defects are presented.

We demonstrate a photonic crystal (PC) cavity formed post-fabrication by locally modifying the refractive index of a chalcogenide PC by using the photosensitivity of the chalcogenide glass.

We demonstrate post-processed, reconfigurable microfluidic double-heterostructure cavities in silicon-based photonic crystal slab waveguides, formed by selective micropipette fluid infiltration. An examination of the induced cavities, performed by evanescent coupling, is presented.

We introduce a simple procedure for high-Q cavity design in photonic crystal heterostructures. The key parameter in the optimization process is the relative position of the resonant frequency within the mode-gap.

We demonstrate reconfigurable microfluidic photonic crystal double-heterostructure cavities by local fluid infiltration of select air holes. Properties of the microfluidic cavities are experimentally studied by evanescent coupling and analyzed by numerical simulations.

We demonstrate post-processed and reconfigurable photonic crystal double-heterostructure nanocavities via selective fluid infiltration. We experimentally investigate the microfluidic structures via evanescent probing from a tapered fiber at telecommunications wavelengths. We demonstrate a cavity with quality factor Q = 4,300. The defect-writing tec...

All-optical switching devices are based on a material possessing a nonlinear optical response, enabling light to control light, and are enjoying renewed interest. Photonic crystals are a promising platform for realizing compact all-optical switches operating at very low power and integrated on an optical integrated circuit. In this review, we show...

We propose a novel concept for creating high-Q cavities in photonic crystal slabs (PCS). These cavities are formed by depositing a polymer layer on top of a photonic crystal membrane fabricated in a high index semiconductor slab. We show that such multilayer structures exhibit a mode-gap and can yield high-Q microcavities with quality factors of Q~...

We demonstrate post-processed and reconfigurable photonic crystal double-heterostructure nanocavities via selective fluid infiltration. We experimentally investigate the microfluidic structures via evanescent probing from a tapered fiber at telecommunications wavelengths. We demonstrate a cavity with quality factor Q = 4,300. The defect-writing tec...

We demonstrate post-processed and reconfigurable photonic crystal double-heterostructures via selective fluid infiltration. Quality factors of Q = 4,300 are obtained from initial measurements. The presented defect-writing technique does not require nanometer-scale alterations in lattice geometry and may be undertaken at any time after device fabric...

We demonstrate postprocessed and reconfigurable photonic crystal double-heterostructure cavities via selective fluid infiltration. We experimentally investigate the microfluidic cavities via evanescent probing from a tapered fiber at telecommunication wavelengths. Fabry-Pérot fringes associated with modes of the induced cavity are in good agreement...

We propose two novel concepts for creating high- Q cavities in photonic crystal slabs (PCS). We show that photonic crystal slab-based double-heterostructure cavities, formed by variations in the refractive index of photosensitive PCS or formed by air-hole infiltration, can have large Q -factors ( Q > 1 x 10⁶).

We design novel photonic crystal slab heterostructures, substituting the air in the holes with liquid crystal, polymer or nano-porous silica. We demonstrate numerically that such cavities can have quality factors up to Q=10⁶.

We present experimental results on photosensitive post-tuning the dispersion of a two-dimensional photonic crystal waveguide made from chalcogenide glass. A 5 nm shift of the resonant wavelength is reported.

We describe the fabrication of low-loss, highly flexible silica fibre nanowires which are used to characterise chalcogenide two-dimensional photonic crystal waveguide circuits and nanocavities. Localised coupling is achieved in good agreement with theory. Crown Copyright r 2007 Published by Elsevier B.V. All rights reserved.

We demonstrate that a highly bend-resistant fiber can be realized. It is shown theoretically that, by introducing both depressed and elevated rings into the cladding, bending loss can be reduced significantly. A fiber based on this design has been fabricated and characterized as a first step toward achieving this goal. The results show that a multi...

The miniaturization of optical devices and their in-tegration for creating adaptive and reconfigurable photonic inte-grated circuits requires effective platforms and methods to con-trol light over very short distances. We present here several tech-niques and objects that we have developed to harness light at the sub-micrometer scale. These new tool...

We propose a novel concept for creating high-Q cavities in photonic crystal slabs (PCSs) composed of photosensitive material. To date, high-Q cavities have been realized through the use of double heterostructures where the lattice geometry is altered via nanolithography. Here, we show that selective postexposure to light of a uniform PCS composed o...

We design novel photonic crystal slab heterostructures, substituting the air in the holes with materials of refractive index higher than n=1. This can be achieved by infiltrating the photonic crystal slab (PCS) with liquid crystal, polymer or nano-porous silica. We find that the heterostructures designed in this way can have quality factors up to Q...