Carsten Ronning

Friedrich Schiller University Jena | FSU · Department of Solid State Physics

Active wavelength‐scale optoelectronic components are widely used in photonic integrated circuitry, however coherent sources of light – namely optical lasers – remain the most challenging component to integrate. Semiconductor nanowire lasers (NWLs) represent a flexible class of light source where each nanowire (NW) is both gain material and cavity;...

Solid-state quantum emitters, pivotal in quantum technology, act as artificial atoms, emitting single photons crucial for quantum computing, communication, and sensing. Integrated into solid matrices, they offer stability and scalability, but face challenges like low-temperature operation and limited light extraction due to high refractive indices....

The sensitivity of molecular spectroscopy based on surface‐enhanced coherent anti‐Stokes Raman scattering (SECARS) is limited by the spectrally overlapping background from nonresonant four‐wave mixing (FWM). While the SECARS signal is mediated by the molecular vibrational eigenstates and exhibits long lifetime (a few picoseconds), the FWM backgroun...

Nanowire‐based plasmonic lasers are now established as nano‐sources of coherent radiation, appearing as suitable candidates for integration into next‐generation nanophotonic circuitry. However, compared to their photonic counterparts, their relatively high losses and large lasing thresholds still pose a burdening constraint on their scalability. In...

Active wavelength-scale optoelectronic components are widely used in photonic integrated circuitry, however coherent sources of light -- namely optical lasers -- remain the most challenging component to integrate. Semiconductor nanowire lasers represent a flexible class of light source where each nanowire is both gain material and cavity; however,...

We investigate hyper-doping, a promising approach to introduce a high concentration of impurities into silicon beyond its solid solubility limit, for its potential applications in near-infrared plasmonics. We systematically explore the incorporation of dopants into silicon using ion implantation and pulsed laser melting annealing processes. Reflect...

Dopant‐selective electrochemical etching (ECE) of gallium nitride (GaN) results in well‐defined porous layers with tunable refractive index, which is extremely interesting for integrating photonic components into nitride technology. Herein, the impact of nitrogen implantation with and without subsequent rapid thermal annealing (RTA) on the porosifi...

Single photon emitters from atomic defects in crystals like hexagonal boron nitride (hBN) are vital for quantum technologies. Although various techniques are devised to obtain defects emission in hBN, simultaneous control over defects position, type, and emission spectrum has not been achieved yet. Here, ion implantation with ¹² C, ²⁰ Ne, and ⁶⁹ Ga...

Conversion electron Mössbauer Spectroscopy (CEMS) studies have been conducted on Fe implanted amorphous and crystalline SiO2 which were annealed in air up to a temperature of 1000oC. For both samples, dramatic changes set in after the 1000oC anneal and the CEM spectra are dominated by strong ferromagnetic sextets. In the amorphous sample, the sexte...

We demonstrate high-harmonic generation for the time-domain observation of the electric field (HHG-TOE) and use it to measure the waveform of ultrashort mid-infrared (MIR) laser pulses interacting with ZnO thin-films or WS2 monolayers. The working principle relies on perturbing HHG in solids with a weak replica of the pump pulse. We measure the dur...

We fabricated shallow silicon gratings for EUV applications utilizing swelling upon irradiation with helium ions through polymer masks. Understanding the effects of fluence, flux and ion energy enables height control between 1 to 20 nm.

We present the integration of four individual erbium-doped waveguide optical amplifiers on a Si 3 N 4 photonic integrated circuit hybrid integrated with a four-lane semi-conductor pump laser diode chip. Each amplifier achieves 15 dB on-chip gain.

We modify the transition temperature of vanadium dioxide films using two different methods: Ar ⁺ irradiation and transition-metal-doping and observe a unified relationship between transition temperature and lattice strain, regardless of modification method or combination thereof.

We demonstrate that metal doping and defect engineering can work in tandem to modify phase-transition temperature and hysteresis of vanadium dioxide films, enabling new opportunities for reconfigurable infrared optics.

Sputtering of metal surfaces can be both a beneficial phenomenon, for instance in the coating industry, or an undesired side-effect, for instant materials subjected to irradiation. While the average sputtering yields are well known in common metals, recent studies have shown that the yields can depend on the crystallographic orientation of the surf...

We demonstrate high-harmonic generation for the time-domain observation of the electric field (HHG-TOE) and use it to measure the waveform of ultrashort mid-infrared (MIR) laser pulses interacting with ZnO thin-films or WS$_2$ monolayers. The working principle relies on perturbing HHG in solids with a weak replica of the pump pulse. We measure the...

We demonstrate high-harmonic generation for the time-domain observation of the electric field (HHG-TOE) and use it to measure the waveform of ultrashort mid-infrared (MIR) laser pulses interacting with ZnO thin-films or WS$_2$ monolayers. The working principle relies on perturbing HHG in solids with a weak replica of the pump pulse. We measure the...

Ion irradiation can cause burrowing of nanoparticles in substrates, strongly depending on the material properties and irradiation parameters. In this study, it is demonstrated that the sinking process can be accomplished with ion irradiation of cube‐shaped Ag nanoparticles on top of silicon; how ion channeling affects the sinking rate; and underlin...

Ion irradiation can cause burrowing of nanoparticles in substrates, strongly depending on the material properties and irradiation parameters. In this study, we demonstrate that the sinking process can be accomplished with ion irradiation of cube-shaped Ag nanoparticles on top of silicon; how ion channeling affects the sinking rate; and underline th...

Since Purcell’s seminal report 75 years ago, electromagnetic resonators have been used to control light-matter interactions to make brighter radiation sources and unleash unprecedented control over quantum states of light and matter. Indeed, optical resonators such as microcavities and plasmonic antennas offer excellent control but only over a limi...

Plasmonic enhancement of nonlinear light–matter interaction can be achieved via dedicated optimization of resonant plasmonic modes that are spectrally matched to the different wavelengths involved in the particular nonlinear optical process. Here, the generation and enhancement of broadband four‐wave mixing (FWM) are investigated in a plasmonic azi...

Tailoring the emission of plasmonic nanowire-based lasers represents one of the major challenges in the field of nanoplasmonics, given the envisaged integration of such devices into on-chip all-optical circuits. In this study, we proposed a mode selection scheme based on distributed feedback, achieved via the external coupling of single zinc oxide...

We analyzed carbon‐implanted high‐temperature annealed (HTA) AlN layers and identified donor‐acceptor pair (DAP) transitions probably between the two most abundant impurities: carbon and oxygen. Both are regarded as the main, hard‐to‐avoid, impurities in crystal growth. Oxygen is believed to lead to absorption in the deep UV below a wavelength of 2...

Semiconductor nanowire lasers can be subject to modifications of their lasing threshold resulting from a variation of their environment. A promising choice is to use metallic substrates to gain access to low-volume Surface-Plasmon-Polariton (SPP) modes. We introduce a simple, yet quantitatively precise model that can serve to describe mode competit...

Heavy and hyper doping of ZnO by a combination of gallium (Ga) ion implantation using a focused ion beam (FIB) system and post‐implantation laser annealing is demonstrated. Ion implantation allows for the incorporation of impurities with nearly arbitrary concentrations, and the laser‐annealing process enables dopant activation close to or beyond th...

Plasmonic gratings are simple and effective platforms for nonlinear signal generation since they provide a well-defined momentum for photon-plasmon coupling and local hot spots for frequency conversion. Here, a plasmonic azimuthally chirped grating (ACG), which provides spatially resolved broadband momentum for photon-plasmon coupling, was exploite...

Application of ZnO as a dilute magnetic semiconductor awaits consensus on the source of reported ferromagnetic behaviour in doped ZnO, whether due to dopant-defect interactions or formation of nanoclusters of the magnetic ion dopants. In a contribution to this search, we report on conversion electron Mössbauer Spectroscopy (CEMS) and magnetization...

The dynamics of color centers, being a promising quantum technology, is strongly dependent on the local environment. A synergistic approach of X‐ray fluorescence analysis and X‐ray excited optical luminescence (XEOL) using a hard X‐ray nanoprobe is applied. The simultaneous acquisition provides insights into compositional and functional variations...

Plasmonic enhancement of nonlinear light-matter interaction can be achieved via dedicated optimization of resonant plasmonic modes that are spectrally matched to the different wavelengths involved in the particular nonlinear optical process. In this work, we investigate the generation and enhancement of broadband four-wave mixing (FWM) in a plasmon...

Tailoring the emission of plasmonic nanowire-based lasers represents one of the major challenges in the field of nanoplasmonics, given the envisaged integration of such devices into on-chip all-optical circuits. In this study, we proposed a mode selection scheme based on distributed feedback, achieved via the external coupling of single zinc oxide...

Semiconductor nanowire lasers can be subject to modifications of their lasing threshold resulting from a variation of their environment. A promising choice is to use metallic substrates to gain access to low-volume Surface-Plasmon-Polariton (SPP) modes. We introduce a simple, yet quantitatively precise model that can serve to describe mode competit...

We demonstrate heavy and hyper doping of ZnO by a combination of gallium (Ga) ion implantation using a focused ion beam (FIB) system and post-implantation laser annealing. Ion implantation allows for the incorporation of impurities with nearly arbitrary concentrations, and the laser-annealing process enables dopant activation close to or beyond the...

A double pulsed laser ablation (DPLA) method has been used to synthesize crystalline boron nanorods, boron nanowires and bamboo‐like boron nanotubes from bulk boron. A q‐switched Nd: YAG laser operating at the first and second harmonic wavelengths with1064 and 532 nm was used to ablate a solid composite boron target doped with 1% Ni and 1% Co in a...

The commonly observed absorption around 265 nm in AlN is hampering the outcoupling efficiency of LEDs emitting in the UV‐C regime. Carbon impurities in the nitrogen sublattice (CN) of AlN are believed to be the origin of this absorption. A specially tailored experiment using a combination of ion‐implantation of boron, carbon and neon with subsequen...

The deployment of plasmonic nanostructures to enhance nonlinear signal generation requires effective far-to-near field coupling and phase matching for frequency conversion. While the latter can be easily achieved at plasmonic hotspots, the former is an antenna problem that requires dedicated structural design and optimization. Plasmonic gratings ar...

Focused ion beam (FIB) processing with low-energy ions has become a standard technique for the manipulation of nanostructures. Many underlying ion beam effects that deviate from conventional high-energy ion irradiation of bulk systems are considered today; however, ion channeling with its consequence of significant deeper penetration depth has been...

Erbium-doped fiber amplifiers revolutionized long-haul optical communications and laser technology. Erbium ions could provide a basis for efficient optical amplification in photonic integrated circuits but their use remains impractical as a result of insufficient output power. We demonstrate a photonic integrated circuit–based erbium amplifier reac...

We demonstrate spatial modification of the optical properties of thin-film metal oxides, zinc oxide (ZnO) and vanadium dioxide (VO2) as representatives, using a commercial focused ion beam (FIB) system. Using a Ga+ FIB and thermal annealing, we demonstrated variable doping of a wide-bandgap semiconductor, ZnO, achieving carrier concentrations from...

Mixed-dimensional hybrid structures have recently gained increasing attention as promising building blocks for novel electronic and optoelectronic devices. In this context, hybridization of semiconductor nanowires with two-dimensional materials could offer new ways to control and modulate lasing at the nanoscale. In this work, we deterministically...

Erbium-doped fiber amplifiers have revolutionized long-haul optical communications and laser technology. Erbium ions could equally provide a basis for efficient optical amplification in photonic integrated circuits. However, this approach has thus far remained impractical due to insufficient output power. Here, we demonstrate a photonic integrated...

Nanocrystalline Ge2Sb2Te5 (GST) was irradiated with Au (700 keV) or Si (150 keV, 700 keV) ions over a wide range of ion fluences. Measuring the radius of curvature of the samples during irradiation revealed significant changes of the depth-integrated stress within the irradiated GST layer. In combination with Raman spectroscopy, the first increase...

Alloyed lead‐free double perovskites display intense photoluminescence, are environmentally friendly, and their devices show long‐term operation. Thanks to these properties, which make them excellent warm white‐emitting materials, they have recently received great attention in lighting applications. An important factor to tune the optical propertie...

Since Purcell's seminal report 75 years ago, electromagnetic resonators have been used to control light-matter interactions to make brighter radiation sources and unleash unprecedented control over quantum states of light and matter. Indeed, optical resonators such as microcavities and plasmonic nanostructures offer excellent control but only over...

We demonstrate spatial modification of the optical properties of thin-film metal oxides, zinc oxide and vanadium dioxide as representatives, using a commercial focused ion beam (FIB) system. Using a Ga+ FIB and thermal annealing, we demonstrated variable doping of a band semiconductor, zinc oxide (ZnO), achieving carrier concentrations from 10^18 c...

Enhancing the light-matter interactions is important for many different applications like sensing, surface enhanced spectroscopies, solar energy harvesting, and for quantum effects such as nonlinear frequency generation or spontaneous and stimulated emission. Hybrid metal-dielectric nanostructures have shown extraordinary performance in this respec...

We report here on the results of comparative experimental measurements of laser energy absorption in a bulk and different morphology nanowire arrays interacting with relativistically intense, ultra-high temporal contrast femtosecond laser pulses. We compare polished, flat bulk samples with vertically and randomly oriented nanowires made of ZnO semi...

Titanium-nitride (TiN) is known as a very promising plasmonic material, which offers many advantages compared to conventional metals commonly used in practical devices. Despite many improvements, TiN still suffers from high losses in the near-infrared (NIR) spectral region, making it less suitable for real-life applications. In this study, we have...

We report the broadband fluorescence enhancement of erbium ions embedded in a single non-resonant reverse nano-focusing waveguide. We measure a large radiative Purcell enhancement of a total emission rate enhancement of > 250 across the entire measured spectrum including the prominent telecoms C-band. Further, we observe the enhancement of single e...

Using ion implantation, we engineered tunable thresholds of optical switches that incorporated frequency-selective surfaces (FSSs) with thin-film VO 2 . We also used a focused ion beam to selectively control any passband of an FSS-VO 2 optical switch.

We demonstrate heavy doping of ZnO by a combination of gallium (Ga) ion implantation using a focused ion beam (FIB) system and post-implantation laser annealing, where we achieved heavily doped ZnO:Ga with free-carrier concentrations of ~9.5 × 10 ²⁰ cm ⁻³ , which results in a plasma wavelength of 1.16 µm.

We demonstrate coupling of a tin-vacancy (SnV) center and a photonic crystal nanobeam cavity in diamond. We observed a 12-hold intensity enhancement of SnV emission and a 16-hold reduction in its lifetime under resonance conditions.

A GaN thin film grown on sapphire substrate was implanted with ⁵⁷Fe and ⁵⁶Fe ions with energies of 60 keV, 160 keV and 370 keV and fluences selected to achieve a homogeneous concentration profile of approximately 2.6 at. % in the film. Implantation induced lattice damage was tracked with conversion electron Mössbauer spectroscopy (CEMS) after annea...

Ion irradiation of bulk and thin film materials is tightly connected to well-described effects such as sputtering or/and ion beam mixing. However, when a nanoparticle is ion irradiated and the ion range is comparable to the nanoparticle size, these effects are to be reconsidered essentially. This study investigates the morphology changes of silver...

Monolayer transition metal dichalcogenides (TMDs) are direct gap semiconductors that hold great promise for advanced applications in photonics and optoelectronics. Understanding the interplay between their radiative and non-radiative recombination pathways is thus of crucial importance not only for fundamental studies but also for the design of fut...