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We report the fabrication of a hollow core fiber (HCF) coupled Faraday rotator mirror component with a total insertion loss below 1.1 dB and demonstrate its use in a polarization-stable all-fiber Michelson interferometer. The signal split into the two interferometer arms is performed using a standard 2 × 2 fused fiber coupler. One of the coupler output ports is permanently and directly connected to the HCF with a low return loss (below -40 dB) and negligible signal coupling into higher-order modes. The demonstrated polarization-insensitive interferometer shows residual peak-to-peak polarization-induced power variations as low as 0.04 dB. The device will be of interest in interferometric applications requiring low thermal sensitivity as the phase drift of light propagating through an HCF is over an order of magnitude less sensitive to temperature than in standard fiber. Moreover, the fiber nonlinearity is almost three orders of magnitude lower in HCFs as compared to standard solid optical fibers.

Modern imaging technologies, including optoacoustic endoscopy, are based on the optoacoustic effect. Much promise is offered by the all-optical fiber-based approach, because fiber has a miniature c...

Due to the fact that hollow-core slabs without formwork are produced without slinging loops (features of manufacturing technology), the issue of installation and transportation of these slabs has been solved. A constructive and technological solution is proposed for a slinging unit, arranged in the body of the slab, without the use of a slinging loop, and having only an anchor rod-dowel through which it is possible to directly sling the slab without using traditional slinging loops. The unit is designed with a reduced metal consumption and does not change the technology for manufacturing hollow-core slabs without formwork. Found and summed up a theoretical basis for calculating the bearing capacity of the proposed slinging unit, arranged in a hollow-core slab without formwork. It was revealed that the bearing capacity of the proposed slinging assembly, arranged in the body of a hollow-core slab, under the action of assembly loads, depends on the force of splitting the concrete of the protective layer located above the anchor rod-dowel of this assembly (all other things being equal). The theoretical data of the study were verified by full-scale tests of plates with slinging units arranged in their body, carried out in accordance with the proposed constructive and technological development. A utility model patent was obtained for the development of a loopless slinging unit for a hollow-core slab without formwork.

In this study, an innovative hollow-core cross-laminated timber (HC-CLT) system was examined in terms of its human-induced vibration performance. Three types of HC-CLT floors were selected as the research objects, namely 3-ply HC-CLT, 5-ply HC-CLT with hollow cores along the transverse direction, and 5-ply HC-CLT with hollow cores along the longitudinal direction. By theoretical analysis, it was found that the hollow cores had a slight impact on the static bending stiffness, and HC-CLT floors had a good potential for structural applications. The HC-CLT floors were then modelled using OpenSees software to assess its dynamic performance, and experimental testing results have validated the modelling method. The HC-CLT floors were excited by single-person, two-person, and five-person slow walking, fast walking, and running. Based on the recorded acceleration at the centroid of the floor, it was realised that the vibration dose values (VDV) of the 5-ply HC-CLT floor with hollow cores along the transverse direction were not larger than those of the solid CLT floor under walking excitations. It indicated that the hollow cores were more effective to distribute along the transverse direction to assure the comfort level. However, the vibration response of the HC-CLT floor under running excitations was larger. By enhancing the beam supporting condition from the two-side to the four-side support, the vibration response of the HC-CLT floor can be effectively reduced.

For the purpose of satisfying the demands of polarization-maintaining fibers for fiber optic gyroscopes, this article proposes a semicircular cladding birefringent hollow-core anti-resonant fiber. The influence of structural parameters on the birefringence, loss, and bending loss of the fiber is studied. The simulation results demonstrate that at 1550 nm, the ultimate loss of the fundamental mode of x and y polarization is 1.76 dB/m and 0.93 dB/m, respectively. The birefringence can reach 1 × 10−4, and the wavelength range of birefringence greater than 10−4 can reach 60 nm. This indicates that it has excellent bending properties. The proposed optical fiber has excellent performance in polarization maintenance and can supply ideas for the research of high-precision fiber optic gyroscopes and other optical devices.

Hollow core photonic crystal fiber is suggested and analyzed in this article for the identification of different blood components present in human blood. In order to visualize the fiber and investigate the performance of that sensor based on COMSOL simulation software, the suggested fiber is numerically analyze in terahertz frequency spectrum from 1.5 to 3 THz to obtain higher relative sensitivity (RS) and NA as well as lower absorption loss and confinement loss (CL) for better sensing applications. The reported hollow core fiber provides better interaction of light and the analytes, so that extremely high RS is achieved at a particular geometric condition. Furthermore, extremely low CL and effective material loss (EML) with high numerical aperture (NA) can be achieved from the suggested sensor which paves the way to apply the fiber in numerous biomedical applications.

The results of spectral diagnostics of an optical discharge (OD) plasma propagating through a hollow-core revolver fibre under the action of repetitively pulsed laser radiation are presented. The revolver fibre is made of silica glass, with a diameter of the hollow core being 20 μm. The peak values of the laser radiation intensity reach 1012 W cm−2at an average Nd : YAG laser power of about 2 W. The time-averaged spectrum of the OD plasma in the visible range has the form of a continuum and is close to the blackbody spectrum with a temperature of 13.3 – 17 kK. The form of the spectrum does not depend on the gas filling of the fibre core (air or argon). In the UV part of the spectrum, lines of neutral silicon are observed, which are indicative of the partial evaporation of the reflecting cladding of the fibre.

Monitoring methane (CH4) concentration is essential in many industrial and environmental applications. Emission of such gases is indeed important to detect for health, safety and environmental reasons. The major risk in all these areas is an explosion hazard, which may occur if methane reaches its Lower Explosive Limit (LEL) of5% concentration in air. For that reason, it is necessary to develop gas sensors to monitor that methane levels below this value. Due to a weak absorption of methane, this gas is difficult to detect using conventional methods.Hollow core photonic crystal fibers (HC-PBF) have emerged as a promising technology in the field of gas sensing. The strong interaction achievable with these fibers are especially advantageous for the detection of weakly absorbing regions of methane. In this paper, we investigated, by full vectorial finite element method (FV-FEM) in Rsoft CAD environment, the dependency of relative sensitivity on the fiber parameters and wavelength. Consequently, we introduced the optimal structureof an index guiding hollow core photonic crystal fiber capable of measuring methane concentrations down to 0.1%in air. The simulations showed that the sensing sensitivity increased with an increase in the core diameter and a decrease in the distance between centers of two adjacent holes.

Time and cost are important factors affecting the successful completion of the construction building project. This study analyses and examines the cost and time comparison of precast and cast-in-situ slabs of a particular building. Taking into account that slab is one of the important structural members, this study will take the hollow core slab in particular which can define as precast prestressed concrete elements contain an empty void inside of it which mostly used for floor, roof slabs and wall panels. The results demonstrate that the precast slab construction time is extremely faster in comparison with the cast-in-situ slab as it took around 31 of working days and 43 days in total after considering the holidays while the precast slab took around 9 working days only and 13 days in total. The results also show that the cast-in-situ slab is inferior in both cost and time duration. As cast-in-situ cost is 3.76 times higher than the precast slab, and the time duration is 3.31 times longer.

A gas refractive index (RI) sensor based on an inornate antiresonant hollow-core fiber (HCF) was theoretically analyzed and experimentally demonstrated. The transmission spectra evolution of the proposed sensor and the resonance intensity variations to the surrounding gas RI were simulated. Theoretical analysis found that the intensity sensitivity of inornate HCF is higher than that of coated HCF. In the experiment, a sensor with a 5 mm-long HCF provided exceptional sensitivity—as high as 2236.1 dB/RIU. The sensitivity was enhanced by improving the resonance intensity of the inornate HCF, which could be further improved by increasing the HCF length. In addition, temperature sensing was performed to resolve the temperature cross-sensitivity issue using a wavelength interrogation method. The proposed RI sensor exhibited the advantages of easily manufactured and with ultrahigh sensitivity.

A typical 1200 mm (48 in.) wide × 200 mm (8 in.) deep prestressed concrete hollow-core unit is analyzed and designed in order to make a comparison between Eurocode 2 and ACI 318-08. This includes calculations for serviceability limit state of stress and moment of resistance, ultimate moment of resistance, ultimate shear capacities, flexural stiffness (that is, for deflection), and cover to pretensioning tendons for conditions of environmental exposure and fire resistance. Concrete cylinder strength is 40 MPa (5.8 ksi), and concrete cube strength is 50 MPa (7.3 ksi). The hollow-core unit is pretensioned using seven-wire helical strands. Worked examples are presented in parallel formation according to Eurocode 2 and ACI 318. For uniformly distributed loads, the design criterion between the service moment to service moment of resistance (Ms/Msr for EC2 and Ms/Msn for ACI 318) and the ultimate design bending moment to ultimate moment of resistance (MEd/MRd for EC2 and Mu/φMn for ACI 318) is well balanced for this example. Usually the service moment is critical unless the amount of prestress is small. For EC2-1-1, flexurally uncracked shear capacity VRd,c is only limiting when the span-to-depth ratio in this example is less than about 35. For ACI 318, flexurally cracked shear capacity φVci is limiting when span-to-depth ratio is 42, showing that shear cracked in flexure will often be the governing criterion.

We propose a highly sensitive hollow core photonic crystal fiber (HCPCF) for liquid sensing in the terahertz (THz) region. Asymmetrical rectangular shaped air holes in the cladding region along with Topas glass as a background material is used to get high sensitivity and low confinement loss. The full vector finite element method (FEM) is used to calculate relative sensitivity and other parameters of the proposed liquid sensor where frequency range is taken from 1 THz to 2 THz. The strut distance variations are also studied in this study to find out minimum strut length to make the proposed sensor fabrication friendly. Numerical analysis shows the maximum relative sensitivity of 91.42% for water, 92.55% for acetic acid and 94.03% for chloroform at optimal conditions along with the minimum confinement loss of 1.06 × 10−9cm−1 for water, 2.02 × 10−10cm−1 for acetic acid and 1.39 × 10−11cm−1 for chloroform. To the best of our knowledge, the proposed HCPCF sensor shows maximum relative sensitivity for liquid.

The use of industrialized elements results in the speed of execution, it avoids waste of materials, and it meets sustainability requirements. The steel profiles and hollow core slabs are included in this scope. The hollow core slab presents superior quality than cast in-situ structural elements, and it is produced in specific environments with technological control and monitoring. In general, a concrete topping is made for smooth and uniform finishing. Studies addressing the structural behavior of steel-concrete composite beams with hollow core slabs with concrete topping are scarce. The present work aims to investigate the behavior of steel-concrete composite beams with hollow core slabs with concrete topping, considering full and partial interaction. Geometric nonlinear analyses are performed based on experimental tests. The steel-concrete composite beams with hollow core slabs with concrete topping are simply supported and subjected to two points loads symmetrically spaced. The influence of concrete topping (50 mm of thickness), the in situ concrete strength (25 MPa, 30 MPa and 40 MPa), the transverse reinforcement diameter (10 mm, 12.5 mm and 16 mm), the interaction degree (shear connectors spaced at 120 mm, 175 mm and 225 mm), and the steel cross section (W360 × 51, W460 × 74 and W530 × 72) are the parameters investigated. The results are discussed, considering these parameters. It was concluded that the concrete topping increased the strength of the composite beams with precast hollow core slabs, the lower the degree of interaction, the greater the ductile behavior of the composite element as a whole. The in-situ infill concrete strength was directly influenced by the steel cross-sectional area, transverse reinforcement rate and interaction degree. The resistance of steel-concrete composite beams with precast hollow core slabs may vary depending on the transverse reinforcement rate and interaction degree. Ductile behavior was observed for all situations, considering partial interaction.

Gedung Kuliah Bersama was modified into ten floors, constructed using precast pretension slabs, namely hollow core slabs on the second to five floors and cast in situ slabs, namely steel deck on floors six to ten. Gedung Kuliah Bersama is located at the UPN “Veteran” East Java in the city of Surabaya. Geologically and tectonically, Surabaya City is in an active fault zone, so that the tectonic activity that occurs can cause damage to building structures and construction materials. Pushover analysis is an analysis that can be used to determine the pattern of structural collapse when an earthquake occurs. Based on the results of the analysis, precast pretension slabs (hollow core slabs) with segments of 1500 mm × 7000 mm × 150 mm with PC Wire reinforcement ϕ7-121 mm and cast in situ (steel deck) slabs with a thickness of 120 mm with wiremesh reinforcement M8-150 mm. The difference in the bending strength of the two types of slabs is 38.73%. The results of the pushover analysis show that the structural performance at the Damage Control (DO) level shows that the building is able to withstand the earthquake that occurs and the risk of casualties is very small.

Precast hollow-core concrete (HC) slabs are widely used in construction, especially in Nordic countries. The combination of prestressing and low self-weight due to the voids makes it possible to bu...

Hollow-core fiber (HCF) has been attracting broad interests in recent decades, and has extended the communication window to longer wavelength, 2 micron. In this article, we present a demonstration of low-latency HCF short-reach optical interconnection at 2 micron, achieving a high single-lane speed of 100 Gbps. High physical speed (near vacuum-light-speed) and high information speed (100-Gbps) optical interconnection with 100-m transmission distance is experimentally achieved with error-free performance. Probabilistically shaped discrete multi-tone (PS-DMT) modulation with entropy loading is employed to accommodate the deteriorated frequency response caused by the mode dispersion in HCF. Compared with conventional solid-core fiber (SCF), HCF contributes 30.95% (1.5-μs per kilometer) latency reduction for the physical link. The system level latency reduction is 28% for 1-km interconnection distance (11% for 100-m), with respect to a microsecond-scale switching network for typical datacenter applications. This work substantially leaps over the 100G milestone of 2-micron HCF optical interconnection, and shows the potentiality with lower latency and further higher capacity.

In the research field of hollow-core optical fiber (HCF), one type of fiber geometry with a leaky mode nature has unexpectedly taken center stage over the last couple of years: the so-called hollow-core anti-resonant fiber (ARF). The guidance mechanism of this ARF has been elucidated explicitly, the optical performance of the fiber has improved significantly, and the range of potential fiber application areas has expanded steadily. This paper will review our continuous efforts to understand, design, and fabricate this hollow-core ARF with the aim of lower loss and wider bandwidth. We also explore the possibility of using an advanced form of ARF in communications applications. In the long journey of looking for optical fibers that provide better performance than conventional solid-core glass fibers, exploitation of the hidden potential of artificial photonic micro-structures will continue to advance.

The paper presents the results of flexural and shear tests up to failure on full-scale hollow-core slabs (HCS) having a depth of 500 mm. A detailed non-linear 2D finite element model is also developed to predict the stress distribution and crack pattern within the slabs, providing a well match with experimental results. Experimental and numerical results are compared with analytical calculations provided by Product Standard EN 1168, highlighting the inaccuracy of technical regulations in predicting shear behavior. The proposed numerical procedure is instead viable and sound for the design and the strength assessment of HCS, and can be extended easily to the analysis of whole floor systems.

A Hollow-core Anti-resonant Fiber (ARF) has many advantages in device applications, such as low cladding density, low nonlinearity, high damage threshold, and excellent polarization characteristics by adjusting the structure and filling a metal. A method of on-line copper coating on the inner hole of hollow-core anti-resonant fiber cladding during drawing is proposed in this paper, and the related polarization characteristic of the ARF is studied. The theoretical and experimental results show that the ARF has good polarization characteristics after coating due to the coupling of copper film and core mode. Polarized light at 860 nm shows the best polarization characteristics. When the ARF is 1 mm, 1.5 mm, and 2 mm in length, its crosstalk is more than 20 dB which works well in communications applications. These characteristics indicate that the ARF coated copper film has a good application prospect in the field of polarization communication.

A state-of-the-art fiber optic gyroscope (FOG) using a 250-m quadrupolar-wound coil of polarization-maintaining hollow-core fiber (HCF) interrogated by a broadened laser is demonstrated. The fiber coil is directly connected to the multi-function integrated optics chip (MIOC) to reduce instabilities and reflections. The HCF FOG is first driven with a broadband source, yielding an angular random walk (ARW) of 2.12 μrad/√Hz and a drift of 0.375 μrad. This drift is 3.4 times lower than reported in any previous HCF FOG. Measuring the loss and ARW versus wavelength of the HCF FOG driven by a tunable narrow-linewidth laser reveals that the HCF supports a dense spectrum of high-scattering surface modes (∼70 modes/nm). The HCF FOG was also interrogated with a 22.5-GHz broadened-laser source, yielding an ARW of 6 μrad/√Hz. This ARW is most likely limited by backscattering mediated by coupling to the high-scattering surface modes. The drift of the HCF FOG driven by the broadened laser was 0.88 μrad. This drift is limited by polarization coupling, and confirms the holding parameter given by the fiber provider for this fiber (10−3 m−1).

Hollow core concrete bridges have been widely constructed in China during the last two decades. The most simple span bridges, with standard lengths of 13 m, 16 m and 20 m, are hollow core concrete bridges. For this type of bridge, the hollow core slabs are precast and simply lifted into place. After the prefabricated hollow core slabs are put in place, the embedded rebars extending from the prefabricated slabs are bound together and the concrete is poured into the space between the slabs, forming a lateral hinge joints between the slabs. A lot of hollow core concrete bridges built early in the 1990s have small hinge joints and very few rebars embedded to form strong lateral connections between the slabs. With an increase of overweight vehicles and the continuous aging of the structures, structural deficiencies such as intensive cracks running through the mid-span and severe deflection progress rapidly resulting in loss of structural capacity and even collapse. The failure of hollow core concrete bridges usually initiates from the failure of the hinge joints, which are the weakest links of the system. When the hinge joints start to lose their ability to hold the adjacent slabs securely, more and more vehicle loads are shifted onto the slabs with deficient hinge joints, which worsens the condition of the slabs and eventually results in systematic failure. To save the hollow core concrete bridges from failure, the authors propose an effective strengthening method to stop the progress of the deficiencies and improve the capacity of the structure.

Steel-concrete slim flooring system using precast concrete hollow core slabs and steel beam with web openings is an innovative construction system designed to combine the high bending resistance of both precast prestressed hollow core slabs and steel beam with web openings. This system can provide floor systems with a minimum constructional depth in comparison with ordinary composite floors. The aim of this study was to evaluate in an exploratory way the shear transferring mechanism between the steel beam with circular web opening and the precast hollow-concrete slab. The shear connection is formed by in-situ concrete passes through the web openings and infill the voids of the precast slabs. One push-out test was conducted to investigate the shear transferring mechanism of shear connection and the experimental results were compared to analytical methods. The shear resistance of the shear connection was predicted with good accurate by analytical methods. Resumo Piso misto de pequena altura com lajes alveolares e viga em aço com aberturas na alma é um tipo inovador de sistema construtivo projetado para aliar o alto desempenho estrutural das lajes pré-fabricadas de concreto protendido e das vigas em aço com aberturas na alma, proporcionando um pavimento de altura reduzida, comparado aos pisos convencionais. Este artigo tem como objetivo avaliar de forma exploratória a contribuição do efeito de pino de concreto como dispositivo mecânico de conexão entre a seção de aço e a laje de concreto. A análise foi realizada com base no resultado experimental de um ensaio de cisalhamento direto, que simula uma tipologia de conexão ao cisalhamento em pisos mistos com lajes alveolares de concreto e viga em aço com abertura circular na alma. Os resultados foram comparados com métodos analíticos. A capacidade resistente da conexão de cisalhamento apresentou boa aproximação com os valores previstos por métodos analíticos.

Recently NANF fiber prototypes have shown a steady decrease in loss. Theory predicts they could eventually outperform conventional fibers, in both loss and optical bandwidth. We investigate their potential impact on long-haul optical communication systems.

We have examined the feasibility of undistorted subpicosecond pulse transmission at peak powers of up to 100 MW and a wavelength of 1030 nm in a hollow-core revolver fibre having a core filled with atmospheric air or argon. A hollow-core revolver fibre has been fabricated which has a low-dispersion (β 2 ≈ – 0.25 ps2 km−1) transmission band in the spectral range of ytterbium and neodymium lasers. Conditions for the nonlinear (soliton) regime of megawatt picosecond pulse propagation over up to 1-km lengths of revolver fibre in atmospheric air and argon at pressures in the range 10−5 to 1 atm have been found theoretically. We have experimentally demonstrated transmission of pulses of 0.8-ps duration and up to ∼100-MW power over an ∼3-m length of revolver fibre with the minimum possible distortion of their shape and spectrum.

The influence of the width of pump pulses (with λ p = 1.026 μm) on the SRS generation of femtosecond pulses in a methane-filled hollow-core fibre is investigated. The width of pump pulses is controlled by transmitting them through an optical dispersion-managed system and thus making them linear frequency-modulated (chirped). Regimes of both the preferred SRS generation of femtosecond pulses at the Stokes wavelength (λ st = 1.464 μm) and the generation of a multiband supercontinuum are experimentally demonstrated. A quantum efficiency of 41 % and a pulse width of 590 fs at the Stokes wavelength are obtained for the 1.026 → 1.464 nm Raman generation.

The use of expanded lightweight concrete for the production of building structures can significantly reduce the weight, which is important in the manufacture of hollow-core slabs; the weight is a significant proportion of the total load. In the current regulatory documents, the physical and mechanical properties of expanded lightweight concrete differ significantly, and sometimes contradict each other. The defects and damages of expanded lightweight concrete hollow-core slabs are described in the case of the kindergarten built near 50 years ago. They appeared during the manufacture of the slabs - uncompacted concrete and uncovered ribs, or in the course of exploitation of the building - normal cracking, holes for pipes and corrosion of reinforcement. Two slabs in emergency condition have numerous longitudinal and shear cracks and chips of concrete caused by overloading. The differences in normative documents and methods of calculations used at the time of designing the kindergarten building and at the present time are shown. The assessment of the technical condition of the expanded lightweight concrete hollow-core slabs considering defects and damages are carried out

In this study, a low-noise Fabry–Perot interference-based method is promoted to measure the longitudinal uniformity of the distance between six pairs of opposite silica–air interfaces within the core of a seven-cell hollow-core photonic bandgap fiber. The experimental results demonstrate that the precision of the method is improved to the subnanometer scale. Based on the test results, a model is established to study the effect of the longitudinal uniformity of the core structure on the fiber loss, and the simulation results indicate that the fiber loss could reach ∼22.73 dB/km, which is consistent with the practical loss value.

High power laser delivery with near-diffraction-limited beam quality, widely used in industry for precision manufacturing, is typically limited to tens of metres distances by nonlinearity-induced spectral broadening inside the glass-core delivery fibres. Anti-resonant hollow-core fibres offer not only orders-of-magnitude lower non-linearity, but also loss and modal purity comparable to conventional beam-delivery fibres. Using a single-mode hollow-core nested anti-resonant nodeless fibre (NANF) with 0.74-dB/km loss, we demonstrate delivery of 1 kW of near-diffraction-limited continuous wave laser light over an unprecedented 1-km distance, with a total throughput efficiency of ~80%. From simulations, more than one order of magnitude further improvement in transmitted power or length should be possible in such air-filled fibres, and considerably more if the core is evacuated. This paves the way to multi-kilometre, kW-scale power delivery – not only for future manufacturing and subsurface drilling, but also for new scientific possibilities in sensing, particle acceleration and gravitational wave detection.

This article proposes and demonstrates a kind of all fiber vector magnetic field sensor based on side-polished hollow-core fiber (SPHCF) coated with magnetic fluid. The magnetic field sensor is composed of a single mode fiber- SPHCF - single mode fiber structure coated with the magnetic fluid. Our designed sensor has good identification of magnetic field orientation. In the experiments, the maximum orientation sensitivity and the intensity sensitivity are 0.19dB/° and -769.05 pm/mT, respectively. Additionally, we found that the changes of the concentration of the magnetic fluid and the sidepolished depth will lead to the change of the higher-order modes involved in the interference as well as the sensitivity of the magnetic field sensor. The proposed vector magnetic field sensor has the advantages of all fiber, simple structure, cost-effective and easy to manufacture, and etc.

We report a study of soliton self-frequency shifting in a hydrogen-filled hollow-core fiber. The combination of hydrogen and short 40-fs input pulses underlies clean and efficient generation of Raman solitons between 1080 and 1600 nm. With 240-nJ input pulses, the Raman soliton energy ranges from 110 to 20 nJ over that wavelength range, and the pulse duration is approximately 45 fs. In particular, 70-nJ and 42-fs pulses are generated at 1300 nm. Numerical simulations agree reasonably well with experiments and predict that microjoule-energy tunable pulses should be possible with higher-energy input pulses.

We demonstrate a low-loss in-fiber bandpass filter based on a tapered antiresonant hollow-core fiber. The insertion loss measured in its passband at 1060 nm is 1.06 dB.

We describe and demonstrate an interferometric side-scattering technique for measuring the microstructure geometry of nested antiresonant hollow-core fiber (NANF). Using this technique, we are able to non-invasively measure the diameters of all the thin tubular capillaries in a NANF with sub-micron accuracy.

Confinement losses of the chalcogenide tubular hollow-core fiber with elliptical nested elements were numerically presented for the mid-infrared region. A 0.19 dB/km confinement loss was calculated at $10.6 \mu \mathrm{m}$ for the proposed fiber designed out of A S2 S 3 chalcogenide glass.

The dispersive wave emission can be enhanced and blue-shifted by selectively exciting high-order-modes (HOMs) in gas-filled hollow-core anti-resonant fiber pumping at 1030 nm with pulses of 30 fs duration and $12\ \mu \mathrm{J}$ energy. Multi-octave supercontinuum spanning 200–1400 nm has been demonstrated by exciting LP02 mode. © 2021 The Author(s)

A new type of anisotropic nested hollow-core anti-resonant fiber is proposed which has propagation loss of

Detection of Nitric Oxide at 5.26 µm is performed using photothermal interferometry and a 25 cm-long antiresonant hollow-core fiber as an absorption cell, reaching a minimum detection limit of 11 ppb for 144 seconds averaging. The proposed configuration shows the full potential of combining novel hollow-core fibers with the photothermal detection techniques, which allows separating the pump and the probe part of the sensor.

Anti-resonant hollow core fiber (ARHCF) has the potential to guide high power laser light in a single mode without fiber damage or unwanted nonlinearities. Here, fabricated ARHCF is explored for the delivery of hundred-Watt level 1064 nm light for directed energy applications.