The point-by-point technique of fabricating fibre-Bragg gratings using an ultrafast laser enables complete control the position each index modification that comprises grating. By tailoring local phase, amplitude and spacing grating's refractive modulations it is possible to create with complex transmission reflection spectra. We report a series grating structures were realized by exploiting these flexibilities. Such include controlled bandwidth, amplitude- phase-modulated sampled (or...

Abstract A key resource for quantum optics experiments is an on‐demand source of single and multiple photon states at telecommunication wavelengths. This letter presents a heralded based on hybrid technology approach, combining high efficiency periodically poled lithium niobate waveguides, low‐loss laser inscribed circuits, fast (>1 MHz) fibre coupled electro‐optic switches. Hybrid interfacing different platforms promising route to exploiting the advantages existing has permitted...

Abstract We report high‐power frequency conversion of a Yb‐doped fiber laser using double‐pass pumped external‐cavity diamond Raman oscillator. Pumping with circular polarization is shown to be efficient while facilitating optical isolation between the pump and laser. achieved continuous‐wave average power 154 W efficiency 50.5% limited by backward‐amplified light in In order prove further scalability, we maximum steady‐state Raman‐shifted output 381 61% excellent beam quality 10 ms pulses,...

Abstract Purpose – The aim of this study was to explore the application rapid manufacturing (RM) production patient specific, custom‐fitting removable partial denture (RPD) alloy frameworks. RPDs are metal frameworks designed retain artificial replacement teeth in oral cavity. Design/methodology/approach undertaken by applied case study. An RPD using computer‐aided design software according well‐established dental technology principles, based on a digitally scanned cast produced from an...

This study explores the application of computer-aided design and manufacture (CAD/CAM) to process electronically surveying a scanned dental cast as prior stage producing sacrificial pattern for removable partial denture (RPD) metal alloy framework. These are designed retain artificial replacement teeth in oral cavity. A produced from an impression patient's mouth was digitally data converted three-dimensional computer file that could be read by (CAD) software. Analysis preparation were...

A 16-channel magnetic induction tomography (MIT) system has been constructed for imaging samples with low conductivities (<10 S m−1) such as biological tissues or ionized water in pipelines. The a fixed operating frequency of 10 MHz and employs heterodyne downconversion the received signals, to kHz, reduce phase instabilities during signal distribution processing. real imaginary components signal, relative synchronous reference, are measured using digital lock-in amplifier. Images...

We report the inscription of low-loss fiber Bragg gratings using focused femtosecond (fs) pulses and a continuous core-scanning technique. This direct-write technique produces high-fidelity Type I-IR that share inherent advantages other methods, such as point-by-point (PbP) method, for which grating period is free parameter. However, here we demonstrate an order magnitude improvement in scattering loss compared to PbP gratings, level comparable with phase-mask-based fs inscription. A...

Laser gain materials possessing high thermal conductivity and robust mechanical properties are key prerequisites for power lasers. We show that diamond, when configured as a Raman laser, enables access to these other extreme properties, providing an important new route brightness beam generation. Recent achievements in pulsed continuous wave oscillators, combining amplifiers, single longitudinal mode oscillators summarized, along with wavelength extension of concepts through adaption pumps,...

We compare and contrast novel techniques for the fabrication of chirped broadband fiber Bragg gratings by ultrafast laser inscription. These methods enable inscription with flexible period profiles thus tailored reflection dispersion characteristics in non-photosensitive optical fibers. Up to 19.5 cm long a spectral bandwidth up 30 nm were fabricated grating was characterized. A maximum group delay almost 2 ns obtained linearly either normal or anomalous velocity dispersion, demonstrating...

Brillouin lasers providing extremely narrow-linewidth are emerging as a powerful tool for microwave photonics, coherent communications, quantum processors, and spectroscopy. So far, laser performance applications have been investigated handful of select materials using guided-wave structures such micro-resonators, optical fibers, chip-based waveguides. Here, we report based on free-space action in an extreme material. Continuous-wave lasing 167 GHz from 532 nm pump is demonstrated diamond...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal Degradation of Bacterial Poly(hydroxybutyric acid): Mechanisms from the Dependence Pyrolysis Yields on Sample ThicknessRoy S. Lehrle and Robert J. WilliamsCite this: Macromolecules 1994, 27, 14, 3782–3789Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://pubs.acs.org/doi/10.1021/ma00092a017https://doi.org/10.1021/ma00092a017research-articleACS PublicationsRequest reuse...

Fiber Bragg gratings inscribed with a femtosecond laser using the point-by-point (PbP) technique have polarization dependent grating strength (PDGS) and exhibit birefringence. In this paper we quantify dependence of these two properties on ellipticity, position in core size micro-voids at center each refractive index modulation. We demonstrate that effective modal for type II written PbP method must be lower than pristine fiber, first time associate an axis such long elliptically-shaped...

Plasma levels of pyridoxal-5'-phosphate (PLP), the active coenzyme form vitamin B6, were found to be significantly lower than normal in 22 out 31 patients with decompensated cirrhosis or subacute hepatic necrosis. There was no significant difference plasma PLP between those liver disease due alcohol and other varieties. When intravenous supplements pyridoxine hydrochloride given only 33% responded an increase PLP. In contrast, all responded, although peak variable, response being less that...

Quasi-cw pumping is used to investigate the high-power characteristics of cw beam conversion in diamond Raman lasers (DRLs). We show that thermal gradients establish DRLs at approximately 50 μs for a 100 μm pump diameter, and thus steady state operation can be reached within 100-300 pulse duration conventional quasi-cw laser technology. Using this approach, steady-state on-time output power 108 W was obtained from an external-cavity DRL during 250 pulses with 34% efficiency. No lens evident,...

We report the demonstration of a single-longitudinal-mode fiber laser operating at 2914 nm, which exhibits spectrometer-limited linewidth <0.4 in 49 mm long holmium/praseodymium co-doped ZBLAN fiber. Narrow-linewidth feedback is provided by Bragg grating inscribed directly using femtosecond point-by-point technique. Measurements temporal stability and coherence confirm that on single longitudinal mode.

Single longitudinal mode (SLM) operation of a 620 nm diamond Raman laser is demonstrated in standing-wave cavity that includes second-harmonic generation element. Mode competition provided by the harmonic mixing shown to greatly increase stability, addition benefits spatial-hole-burning-free gain medium. Using multi-longitudinal 1064 Nd:YAG pump power 321 W and linewidth 3.3 GHz, SLM powers 38 at 11.8 1240 were obtained. The results indicate simple oscillators pumped multimode Yb or Nd pumps...

We report a narrowband and tunable diamond Raman laser generating eye-safe radiation suitable for water vapor detection. Frequency conversion of pump operating from 1063 to 1066 nm the second order Stokes component in an external standing-wave cavity yielded 7 W multimode output power wavelength range 1483 1488 at efficiency 21%. Stable single longitudinal mode operation was achieved over whole tuning low (0.1 W), whereas incorporation volume Bragg grating as coupler enabled much higher...

Deep high-dispersion spectroscopy of Galactic photoionized gaseous nebulae, mainly planetary nebulae and HII regions, has revealed numerous emission lines. As a key step spectral analysis, identification lines hitherto mostly been done manually, which is tedious task, given that each line needs to be carefully checked against huge volumes atomic transition/spectroscopic database reach reliable assignment identity. Using Python, we have developed line-identification code PyEMILI, significant...

Abstract Deep high-dispersion spectroscopy of Galactic photoionized gaseous nebulae, mainly planetary nebulae and H ii regions, has revealed numerous emission lines. As a key step spectral analysis, identification lines hitherto mostly been done manually, which is tedious task, given that each line needs to be carefully checked against huge volumes atomic transition/spectroscopic data reach reliable assignment identity. Using Python , we have developed line-identification code PyEMILI,...

This article presents the use of digital image processing using hue, saturation, and intensity measurements as a technique for color analysis chronic wounds on skin. An adaptive spline was used to segment wound boundary in images venous leg ulcers. further approximate position The amount slough within site quantified software developed compared with grading system based visual inspection by an experienced clinician, results were deriving Kappa (K) statistic. There moderate agreement over all...

Correlating measurements from differential scanning calorimetry, freeze-fracture freeze-etch electron microscopy, and survival of twigs after two-step cooling experiments, we provide strong evidence that winter-hardened Populus balsamifera v. virginiana (Sarg.) resists the stresses freezing below -28 degrees C by amorphous solidification (glass formation) most its intracellular contents during slow (</=5 per hour). It is shown other components medium go through glass transitions at about -45...