Heike Ebendorff-Heidepriem

• The University of Adelaide

The nitrogen-vacancy (NV) center is a photoluminescent defect in diamond that exists in different charge states, NV$^-$ and NV$^0$, that are sensitive to the NV's nanoscale environment. Here, we show that photoluminescence (PL) from NV centers in fluorescent nanodiamonds (FNDs) can be employed for all-optical voltage sensing based on electric field...

Fluorescence‐guided surgery is an increasingly common technique in neurosurgery, where 5‐aminolevulinic acid induces fluorescence in high‐grade gliomas, aiding in tumor resection and improving surgical outcomes. Reliable detection of malignant tissue fluorescence depends critically upon the clinical imaging system. Factors such as nonuniform excita...

Diamond-embedded optical fibers with negatively charged nitrogen-vacancy (NV) centers have great potential for remote and distributed magnetic field sensing. However, the magnetic field sensitivity of the currently proposed fiber configuration is limited. This work uses a numerical approach to investigate the effect of structured diamonds on enhanc...

In this semi‐quantitative study, laser crystal microparticles which are potentially capable of generating mid‐infrared (MIR) light are incorporated into MIR transmitting optical fibers using a volumetric interface doping technique that combines interface doping with volumetric doping. Using confocal microscopy with a refractive index matching fluid...

Distinguishing between microscopic variances in temperature in both space and time with high precision can open up new opportunities in optical sensing. In this paper, we present a novel approach to optically measure temperature from the fluorescence of erbium:ytterbium doped tellurite glass, with fast temporal resolution at micron-scale localisati...

Single-fiber-based sensing and imaging probes enable the co-located and simultaneous observation and measurement (i.e., ‘sense’ and ‘see’) of intricate biological processes within deep anatomical structures. This innovation opens new opportunities for investigating complex physiological phenomena and potentially allows more accurate diagnosis and m...

Optical fiber pressure sensing is of significant interest for industrial process monitoring and acoustic sensing. However, the direct detection of pressure changes along an optical fiber with minimal crosstalk is a significant challenge due to the low stress-optic coefficient of glass and interferences from temperature, bending, and strain. Here we...

We demonstrate single-frequency 1550 nm pulsed amplification using Er/Yb co-doped multimode fiber, achieving 1.5 kW peak power and 11 dB gain at 10 kHz. Adjusting the seed wavefront, we obtained good output beams while maintaining gain and linewidth.

The propagation of coherent light in multimode optical fibers results in a speckled output that is both complex and sensitive to environmental effects. These properties can be a powerful tool for sensing, as small perturbations lead to significant changes in the output of the fiber. However, the mechanism to encode spatially resolved sensing inform...

The fabrication of a stable, reproducible optical imaging phantom is critical to the assessment and optimization of optical imaging systems. We demonstrate the use of an alternative material, glass, for the development of tissue-mimicking phantoms. The glass matrix was doped with nickel ions to approximate the absorption of hemoglobin. Scattering l...

Silicate glasses with metallic nanoparticles (NPs) have been of intense interest in art, science and technology as the plasmonic properties of these NPs equip glass with light modulation capability. The so-called striking technique has enabled precise control of the in situ formation of metallic NPs in silicate glasses for applications from coloure...

The key challenge for high-power delivery through optical fibers is overcoming nonlinear optical effects. To keep a smooth output beam, most techniques for mitigating optical nonlinearities are restricted to single-mode fibers. Moving out of the single-mode paradigm, we show experimentally that wavefront-shaping of coherent input light to a highly...

The propagation of coherent light in multimode optical fibers results in complex light patterns known as speckle. This effect has historically made understanding and controlling the light transport in these fibers extremely difficult, with successes such as imaging still being restricted to special cases. This complexity can also be a powerful tool...

Silicate glasses with metallic nanoparticles (NPs) have been of intense interest in art, science and technology as the plasmonic properties of the metallic NPs equip glass with light modulation capability. The so-called striking technique has enabled precise control of the in-situ formation of metallic NPs in silicate glasses for applications from...

Transition-metal dichalcogenides [1] (TMDs) are intriguing semiconductors for photonics because of their direct bandgap in the Visible to NIR range, their nature of van der Waals materials, and extraordinary light-matter-interaction per unit thickness [1]. Two-dimensional (2D) TMDs also exhibit strong optical nonlinearity and thus are highly sought...

The key challenge for high-power delivery through optical fibers is overcoming nonlinear optical effects. To keep a smooth output beam, most techniques for mitigating optical nonlinearities are restricted to single-mode fibers. Moving out of the single-mode paradigm, we show experimentally that wavefront-shaping of coherent input light that is inci...

Objectives: Diamond machining of lithium silicate glass-ceramics (LS) induces extensive edge chipping damage, detrimentally affecting LS restoration functionality and long-term performance. This study approached novel ultrasonic vibration-assisted machining of pre-crystallized and crystallized LS materials to investigate induced edge chipping dama...

Optimization of all the process parameters for laser powder bed fusion (L-PBF), considering the effects of individual parameters on Ti6Al4V fabricated parts, can be complex and challenging. Therefore, for the first time, the effects of three main variable process parameters (laser power, scan speed, and hatch spacing) on three outcomes parameters (...

We demonstrate a multipoint optical fiber pressure sensor for high temperature operation using multimode interference. Each sensing element consists of a four-hole asymmetric multimode fiber acting as the pressure sensing fiber, spliced between two standard polarization-maintaining single mode fibers. Multiple sensing elements are serially connecte...

Optical fiber pH sensors work by observing a change in the indicator’s optical signal caused by variations in pH and these indicators can be immobilized onto the surface of an optical fiber using a polymer matrix. How the composition of the polymer matrix changes pH detection range using the indicator (5(6)-carboxynaphthofluorescein (CNF)) has not...

Optical techniques hold great potential to detect and monitor disease states as they are a fast, non‐invasive toolkit. Raman spectroscopy (RS) in particular is a powerful label‐free method capable of quantifying the biomolecular content of tissue, but lacks information about tissue morphology due to its inability to rapidly assess a large field of...

Silica-based optical fibres are a workhorse of nonlinear optics, providing ready access to a range of nonlinear phenomena including solitons and self-phase modulation. However, they have one fundamental limitation: due to the amorphous nature of silica, they do not exhibit second-order nonlinearity, except for negligible contributions from surfaces...

A detailed study was carried out to gain a better understanding of the microstructural differences between Ti-6Al-4V parts fabricated via the conventional powder metallurgy (PM) and the laser powder bed fusion (L-PBF) 3D printing routes. The parts were compared in terms of the constituent phases in the microstructure and their effects on the micro-...

Large core soft glass fibers have been demonstrated to be promising candidates as intrinsic fiber sensors for radiation detection and dosimetry applications. Doping with rare earth ions enhanced their radiation sensitivity. SiO2-Al2O3-La2O3 (SAL) glasses offer easy fabrication of large core fibers with high rare earth concentration and higher mecha...

This is an introduction to the feature issue of Optical Materials Express on Non-Oxide Optical Materials.

Dispersive Waves The optical properties of optical fibers with exposed cores can be straightforwardly tuned by the deposition of high refractive index nano‐films (green) inducing tailored resonances. In article number 2103864 by Markus A. Schmidt and co‐workers, a precise dispersion design and tailored supercontinuum generation is enabled through p...

Anisotropy in the mechanical properties of Laser Powder Bed Fusion (L-PBF)-fabricated titanium parts, which could be problematic in service, is dependent on the build directions and may be mitigated by post-fabrication treatments such as surface machining or heat treatment. However, investigation of the anisotropy in truly as-printed conditions, i....

Widely wavelength‐tunable femtosecond light sources in a compact, robust footprint play a central role in many prolific research fields and technologies, including medical diagnostics, biophotonics, and metrology. Fiber lasers are on the verge in the development of such sources, yet widespan spectral tunability of femtosecond pulses remains a pivot...

Heavy metal oxide glasses (HMO) based on the glass-network formers tellurium and germanium dioxide (TeO2 and GeO2) have lower phonon energies, higher rare-earth (RE) ion solubility, higher optical nonlinearity and higher mid-IR transparency than silica. In addition, they are more robust and stable than mid-IR fluoride and chalcogenide glasses as th...

We present a high-temperature interferometric pressure sensor using a simple-design and easy-to-fabricate pure silica four-hole novel microstructured optical fiber. The asymmetric geometry of the fiber allows hydrostatic pressure to induce stress at the optical fiber core, which converts to an interferometric shift. The large core of the fiber supp...

We present a novel strain sensor based on a hybrid Fabry–Perot interferometer (HFPI), which is mainly constructed by a cascade of a suspended-core fiber (SCF) and a hollow-core fiber (HOF) between two single-mode fibers (SMFs). When the optical path length (OPL) is matched to some extent, the reflection spectrum of the proposed HFPI demonstrates de...

We report a specklegram pressure sensor using a pure silica six-hole novel microstructured optical fiber. This simple and low-cost sensor has the potential for pressure measurement at high temperature harsh environment applications.

Stimulated Brillouin scattering (SBS) induced by narrow-linewidth high power pulses in a multimode fiber (MMF) is suppressed via controlling the input wavefront, presenting a new route to scaling power in high power fiber amplifiers.

We report a nonlinear photonics platform possessing a substantial second-order susceptibility and demonstrate the enhancement of second-harmonic generation in resonance with excitons. Here, exposed-core fibers, functionalized with MoS 2 monolayers provide a long light-matter interaction scheme.

The use of synthetic nanomaterials as contrast agents, sensors, and drug delivery vehicles in biological research primarily requires effective approaches for intracellular delivery. Recently, the well-accepted microelectrophoresis technique has been reported to exhibit the ability to deliver nanomaterials, quantum dots (QDs) as an example, into liv...

A reflective Fabry-Perot interference (FPI) label-free biosensor based on Vernier effect is designed and implemented for in situ real-time DNA hybridization detection. The sensor is made by splicing single-mode fiber (SMF), a segment of C-type fiber and SMF. The Vernier effect occurs between the solid cavity FPI and the air cavity FPI. In our exper...

We report a pure silica microstructured optical fiber based interferometric sensor for pressure measurement at high temperature up to 800°C. Using a Fourier technique and sensitivity matrix approach the sensor can compensate the cross-sensitivity of temperature on the pressure measurement. The sensor is demonstrated to exhibit excellent stability w...

In this paper, a novel platform for simultaneous measurement of relative humidity (RH) and temperature using dual FabryPerot interferometers (FPIs) based on C-shaped fiber was demonstrated. The sensor was composed by splicing two sections of C-shaped fiber between single mode fiber (SMF). Polydimethylsiloxane (PDMS) and polyvinyl alcohol (PVA) are...

Calcium ions (Ca2+) take part in intra‐ and inter‐cellular signaling to mediate cellular functions. Sensing this ubiquitous messenger is instrumental in disentangling the specific functions of cellular sub‐compartments and/or intercellular communications. In this review, the authors first describe intra‐ and inter‐cellular Ca2+ signaling in relatio...

We report the substantial second-harmonic generation produced from exposed core optical fibers, coated with single-layer MoS2 crystals, grown by a one-step CVD process. This second-order process is tunable and supported by intermodal phase matching.

A compact microfluidic Raman detection system based on a single-ring negative-curvature hollow-core fiber is presented. The system can be used for in-line qualitative and quantitative analysis of biochemicals. Both efficient light coupling and continuous liquid injection into the hollow-core fiber were achieved by creating a small gap between a sol...

Amid the search for efficient terahertz transmission and gas sensing, all-polymer terahertz waveguides attract significant interest due to their compactness and capability for providing environmentally robust systems. The high loss within metals and dielectrics in the terahertz range makes it challenging to build a low loss, mechanically stable, an...

A label-free DNA biosensor based on exposed core microstructured optical fiber for in-situ real-time DNA detection has been presented and experimentally demonstrated. The sensor is fabricated by splicing a section of tapered exposed core fiber (ECF) between two single-mode fibers (SMFs), forming a multimode Mach-Zehnder interferometer (MZI). The EC...

Silica-based optical fibers are a workhorse of nonlinear optics. They have been used to demonstrate nonlinear phenomena such as solitons and self-phase modulation. Since the introduction of the photonic crystal fiber, they have found many exciting applications, such as supercontinuum white light sources and third-harmonic generation, among others....

Anisotropy in the mechanical properties with respect to the build direction of Selective Laser Melting (SLM) fabricated titanium parts is a known, challenging problem, which can be mitigated using a post processing method such as heat treatment. This paper investigates the potential sources of anisotropy associated with SLM fabricated Ti64 parts an...

In this manuscript, we report on, to the best of our knowledge, the first experimental realization of a multimode interference device based on self-image phenomenon accomplished by using a microstructured-cladding exposed-core fiber set in a singlemode-multimode-singlemode (SMS) configuration. Its application as a refractive index sensor is also de...

Formaldehyde (FA) is widely applied as a fixative for proteins such as collagen. Current studies have confirmed that the reversible oligomer-to-monomer equilibrium of FA in aqueous solution and the proportion of FA monomer was a significant factor affecting tissue fixation. Since the hydrolysis of FA oligomers is a dynamic process affected jointly...

Whispering gallery modes (WGMs) in micro-resonators are of interest due to their high Q-factors. Ultra-thin fiber tapers are widely deployed to couple light into micro-resonators but achieving stable and practical coupling for out-of-lab use remains challenging. Here, a new WGM coupling scheme using an exposed-core silica fiber (ECF) is proposed, w...

Transition-metal dichalcogenides (TMDs) are particularly appealing for photonics due to their rich photophysical effects and strong light-matter-interaction per unit length. Two-dimensional (2D) TMDs also exhibit strong optical nonlinearity which opens up novel potential applications in nonlinear optics. However, the total optical response of TMDs...

DOI: 10.1002/elps.202000388 The cover picture shows monodispersed quantum dots with negative surface charges being injected through a fine‐tipped glass micropipette into the cytoplasm of a live human embryonic kidney cell (roughly 20–30 μm in length) via small electrical current (−0.2 nA). The average hydrodynamic diameter of quantum dots is 13.2–3...

Diamonds containing the negatively charged nitrogen-vacancy centre are a promising system for room-temperature magnetometry. The combination of nano- and micro-diamond particles with optical fibres provides an option for deploying nitrogen-vacancy magnetometers in harsh and challenging environments. Here we numerically explore the coupling efficien...

Studying the mechanical properties of Selective Laser Melting (SLM) fabricated titanium parts built in a horizontal direction, parallel to the substrate, in a truly as-built condition, has always been a challenge. The problem is mainly related to the stress relaxation of horizontal parts after removal from the substrate, which causes a noticeable l...

Nanoparticles with specific properties and functions have been developed for various biomedical research applications, such as in vivo and in vitro sensors, imaging agents and delivery vehicles of therapeutics. The development of an effective delivery method of nanoparticles into the intracellular environment is challenging and success in this ende...

In a previous study, we compared experiments on drawing of axisymmetric tubular optical fibres to a mathematical model of this process. The model and experiments generally agreed closely. However, for some preforms and operational conditions, the internal channel of the drawn fibre was larger than predicted by the model. We have further investigate...

A new approach to optical fiber sensing is proposed and demonstrated that allows for specific measurement even in the presence of strong noise from undesired environmental perturbations. A deep neural network model is trained to statistically learn the relation of the complex optical interference output from a multimode optical fiber (MMF) with res...

The tracking of small particles is an important but challenging task for biological applications such as disease diagnostics and medical research. Current methods are limited to the use of bulky instruments such as flow cytometers and microscopes. Here, a novel technique for the detection and measurement of micron-scale optical scatterers using a f...

Thermochromic window technologies promise energy-saving capabilities through intelligent regulation of solar irradiation indoor penetration. Although improvements have been made, nanoparticle thermochromic coated glazing technology has not yet achieved optimal balance between luminous transmittance and solar modulating capability. While luminous tr...

Fig. 4 in reference [1] is after [2] .

Depositing high refractive index nanofilms with controlled thicknesses on exposed core fibers enables thickness tunable supercontinuum generation. Thickness gradients along the fiber allow for optimizing for spectral flatness and extension of bandwidth toward the infrared.

Monitoring nitrate ions is essential in agriculture, food industry, health sector and aquatic ecosystem. We show that a conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), can be used for nitrate sensing through a process in which nitrate ion uptake leads to oxidation of PEDOT and change of its optical properties. In this study, a new pla...

We experimentally demonstrate a single-layer terahertz dielectric metasurface. The metasurface consists of an array of sub-wavelength fibers. It is shown that this single-layer terahertz metasurface has high transmission window and can also behave like a terahertz magnetic or electric mirror due to the excitation of resonances in the fibers. It is...

Green lasers are coupled into nanostructured, exposed‐core fibers, functionalized with monolayer transition metal dichalcogenide crystals in a scalable chemical vapor deposition process by Antony George, Andrey Turchanin, Falk Eilenberger, and co‐workers in article number 2003826. The laser light excites excitons in the monolayer, re‐emiting red ph...

We use exposed core optical fibers, coated with single-layer MoS2 and WS2 crystals, grown in place, to demonstrate in-fiber exciton excitation, photoluminescence collection, and enhanced third-harmonic generation.

For lead‐germanate glass fibers, reducing the content of hydroxyl (OH) groups and the formation of metallic Pb species is essential to pave the way for their applications as low‐loss mid‐IR fiber optics since OH and metallic Pb species cause intense absorption and scattering loss, respectively, in the mid‐IR spectral range. The first part of this s...

Oxidative stress is intimately linked to cellular energy balance and occurs when there is an imbalance between production and accumulation of reactive oxygen species in cells and tissues and the ability of a biological system to keep in a redox steady state. While protein carbonyls are an easily detectable marker of oxygen metabolism and oxidative...

The potential of a Yb³⁺/Ho³⁺ co-doped lead-germanate glass as a laser gain medium around 2 µm is investigated by spectroscopic measurements and rate equation modelling. The glass, based on the molar composition of 56GeO2-31PbO-4Ga2O3-9Na2O and co-doped with 1.5 mol% Yb2O3 and 0.4 mol% Ho2O3, possesses a broad Ho³⁺ emission spectrum covering ∼1.8 µm...

A hollow core antiresonant photonic crystal fiber (HC-ARPCF) is analyzed for terahertz applications. A numerical analysis of the proposed fiber is first carried out to minimize coupling between the core and cladding modes. The modeling of the scaled-up and inhibited coupling fiber is carried out by means of a Finite Element Method (FEM), which is t...

Reducing the mid‐infrared attenuation loss due to absorption of hydroxyl (OH) groups and scattering of metallic Pb species for lead‐germanate glass is essential to pave the way for their applications as low‐loss mid‐infrared fiber optics. In the first part of this study, we report the understanding of the factors that determine dehydration efficien...

Atomically thin transition metal dichalcogenides are highly promising for integrated optoelectronic and photonic systems due to their exciton‐driven linear and nonlinear interactions with light. Integrating them into optical fibers yields novel opportunities in optical communication, remote sensing, and all‐fiber optoelectronics. However, the scala...

Plasmonic spectroscopy has emerged as a powerful technique for interrogation of light in the subwavelength regime. Realization of active plasmonic elements on optical fibers can simplify the optical design, allow for performing remote tasks and thus extend the scope of plasmonic utilization. However, the optimization of fiber optics for improving t...

Nanostructure patterning on optical fibers enables miniaturized optrodes for photonic and plasmonic applications. Here we report a direct nanoimprint technique to produce high-quality nanostructure arrays on optical fiber endfaces. It has only one single step: imprinting optical fiber tips against a mold with nanostructures at the elevated temperat...

Plasmonic devices using periodic metallic nanostructures have recently gained tremendous interest for color filters, sensing, surface enhanced spectroscopy, and enhanced photoluminescence, etc. However, the performance of such plasmonic devices is severely hampered by the solid substrates supporting the metallic nanostructures. Here, a strategy for...

We report the understanding of the factors (gas types, flow rate, dehydration agents, etc.) that determine dehydration efficiency and metallic Pb formation during the lead-germanate glass melting process, as well as the fabrication of low loss lead-germanate glass fiber through extrusion method.

Diamond containing the nitrogen-vacancy (NV) center is emerging as a significant sensing platform. However, most NV sensors require microscopes to collect the fluorescence signals and therefore are limited to laboratory settings. By embedding micron-scale diamond particles at an annular interface within the cross section of a silicate glass fiber,...

Quantitative polymerase chain reaction (qPCR), the real-time amplification and measurement of a targeted DNA molecule, has revolutionized the biological sciences and is routinely applied in areas such as medical diagnostics, forensics, and agriculture. Despite widescale use of qPCR technology in the lab, the availability of low-cost and high-speed...