Versatile and widely tunable mid-infrared erbium doped ZBLAN fiber laser

We report on a long wavelength emitting rare earth doped fiber laser with emission centered at 3.5 {\mu}m and tunable across 450 nm. The longest wavelength emission was 3.78 {\mu}m, which is the longest emission from a fiber laser operating at room temperature. In a simple optical arrangement employing dielectric mirrors for feedback, the laser was capable of emitting 1.45 W of near diffraction limited output power at 3.47 {\mu}m. These emission characteristics compliment the emission from quantum cascade lasers and demonstrate how all infrared dual wavelength pumping can be used to access high lying rare earth ion transitions that have previously relied on visible wavelength pumping

Roadmap on optical sensors

Optical sensors and sensing technologies are playing a more and more important role in our modern world. From micro-probes to large devices used in such diverse areas like medical diagnosis, defence, monitoring of industrial and environmental conditions, optics can be used in a variety of ways to achieve compact, low cost, stand-off sensing with extreme sensitivity and selectivity. Actually, the challenges to the design and functioning of an optical sensor for a particular application requires intimate knowledge of the optical, material, and environmental properties that can affect its performance. This roadmap on optical sensors addresses different technologies and application areas. It is constituted by twelve contributions authored by world-leading experts, providing insight into the current state-of-the-art and the challenges their respective fields face. Two articles address the area of optical fibre sensors, encompassing both conventional and specialty optical fibres. Several other articles are dedicated to laser-based sensors, micro- and nano-engineered sensors, whispering-gallery mode and plasmonic sensors. The use of optical sensors in chemical, biological and biomedical areas is discussed in some other papers. Different approaches required to satisfy applications at visible, infrared and THz spectral regions are also discussed

The global naturalized Alien Flora (GloNAF) database

This dataset provides the Global Naturalized Alien Flora (GloNAF) database, ver-sion 1.2. Glo NAF represents a data compendium on th e occurrence and identit y of naturalizedalien vascular plant taxa across geographic regions (e.g. countries, states, provinces, districts,islands) around the globe. The dataset includes 13,939 taxa and covers 1,029 regions (including381 islands). The dataset is based on 210 data sources. For each ta x on-b y-region combination, wepr ovide information on whether the tax on is consider ed to be naturalized in the specific region(i.e. has established self-sustaining popula tions in the wild). Non-native taxa are marked as“alien”, when it is not clear whether they are naturalized. To facilitate alignment with other plantdatabases, we pro v ide f or each taxon the name as given in the original data source and the stan-dardized taxon and family names used by The Plant List Version 1.1 (http://www.theplantlist.org/). We pro vide an ESRI shapefile including polygons f or each region and informa tion on whetherit is an island or a mainland region, the country and the Taxonomic Databases Working Group(TDWG) regions it is part of (TDWG levels 1–4). We also provide several variables that can beused to filter the data according to quality and completeness of alien taxon lists, which varyamong the combinations of regions and da ta sources. A pre vious version of the GloNAF dataset(version 1.1) has already been used in several studies on, for example, historical spatial flows oftaxa between continents and geographical patterns and determinants of naturalization across dif-ferent taxonomic groups. We intend the updated and expanded GloNAF version presented hereto be a global resource useful for studying plant inv asions and changes in biodiversity from regio-nal to global scales. We release these data into the public domain under a Crea ti ve CommonsZer o license waiver (https://creati v ecommons.org/share-y our -work/public-domain/cc0/). Wheny ou use the da ta in your publication, we request that y ou cite this da ta paper. If GloN AF is amajor part of the data analyzed in your study, you should consider inviting the GloNAF coreteam (see Metadata S1: Originators in the Overall project description) as collaborators. If youplan to use the GloNAF dataset, we encourage y ou to contact the GloNAF core team to checkwhether there have been recent updates of the dataset, and whether similar analyses are already ongoing

Development of dual-wavelength pumped mid-infrared fibre laser

There is an urgent need for efficient and compact sources of coherent mid-infrared wavelength radiation (3-5 μm). Cost-effective and bright mid-infrared sources will lead to exciting new sensing applications, ranging from the remote sensing of greenhouse gases, such as CO₂ and methane, to analysis of trace gases in exhaled breath for disease marker identification. The last decade has seen a continuing increase in the output power of various types of mid-infrared sources, such as optical parametric oscillators and amplifiers, quantum cascade lasers and fibre lasers. However, advances in brightness, efficiency, peak power and tunability are still necessary for many applications. In this thesis, we describe a new concept for a fibre laser based on Er³⁺ doped ZBLAN glass that operates in the mid-infrared with lasing centred around 3.5 μm. We used a novel dual-wavelength pumping (DWP) scheme to achieve world-leading efficiency for this material and an output power of 260 mW. The DWP technique uses long-lived excited states in our Er³⁺ ion doped ZBLAN glass gain medium to improve the Stokes efficiency. A low power, 985 nm pump source excites ions from the ⁴I₁₅ ̷₂ ground state to the long lived ⁴I₁₁ ̷₂ state. A large fraction of the ion population can be stored in this level because of its long lifetime, creating a \virtual ground state." A concurrent 1973 nm pump source is then used as the main pump source. This pump excites the ions further to the upper laser level ⁴F₉ ̷₂. Post lasing, the 1973 nm pump cycles the ions between the \virtual ground state" at ⁴I₁₁ ̷₂ and the ⁴F₉ ̷₂ level. The first pump at 985 nm maintains the population in the “virtual ground" as this population is diminished by spontaneous emission and energy-transfer processes, which eject ions from the lasing cycle. In this thesis, we review the literature and the current state-of-the-art in mid-infrared fibre lasers. An overview of the spectroscopic properties of Er³⁺:ZBLAN relevant to mid-infrared operation is presented. The difficulties and issues associated with the creation of mid-infrared radiation are discussed and our spectroscopic investigations of ZBLAN glass and glass fibres are summarised. Multiple wavelengths were used as pump sources for our DWP laser. Our investigation of the optimal wavelength for the DWP technique and the development of suitable sources is described as well. The 3.5 μm laser system is discussed, including the full characterisation of the laser. The thesis is concluded with a summary of the results and an outlook for the future.Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2015