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We report on the development of a new primary thermometer based upon high-precision spectroscopy of mercury vapors in the deep-ultraviolet region for the practical realization of the new kelvin. The line profile of the (6s 2)1 S 0 → (6s6p)3 P 1 intercombination transition of the 200Hg bosonic isotope is observed with a high spectral fidelity using a coherent radiation source at 253.7 nm. This latter consists of a near-IR external cavity diode laser followed by a double-stage second-harmonic generation apparatus. Metrology grade UV spectroscopy is demonstrated by locking the diode laser to a self-referenced optical frequency comb synthesizer.

We present the design study of an innovative scheme to generate high repetition rate (multi-MHz-class) THz radiation pulses by using an Energy Recovered Super Conducting Linac operating in Continuous Wave mode driving a Free-Electron Laser Oscillator. The FEL performance is illustrated for one and two color operation. Start-to-end simulations are presented to assess the capability of this scheme for typical values of wavelengths of interest in the 10–50μm (6–30 THz) range.

We investigated a set of nineteen

Endovascular repair of abdominal aortic aneurysm has become a milestone in the treatment of patients with abdominal aortic aneurysm.Technological improvement allows treatment in more and more complex cases. This review summarizes all grafts available in the market. At the best of our knowledge a complete review of most important trial on this topic are provided and at least technical tips and tricks for standard cases are recapitulated.

Diabetic foot (DF) is a chronic and highly disabling complication of diabetes. The prevalence of peripheral arterial disease (PAD) is high in diabetic patients and, associated or not with peripheral neuropathy (PN), can be found in 50% of cases of DF. It is worth pointing out that the number of major amputations in diabetic patients is still very high. Many PAD diabetic patients are not revascularised due to lack of technical expertise or, even worse, negative beliefs because of poor experience. This despite the progress obtained in the techniques of distal revascularisation that nowadays allow to reopen distal arteries of the leg and foot. Italy has one of the lowest prevalence rates of major amputations in Europe, and has a long tradition in the field of limb salvage by means of an aggressive approach in debridement, antibiotic therapy and distal revascularisation. Therefore, we believe it is appropriate to produce a consensus document concerning the treatment of PAD and limb salvage in diabetic patients, based on the Italian experience in this field, to share with the scientific community.

We report on a new implementation of Doppler broadening thermometry based on precision absorption spectroscopy by means of a pair of offset-frequency locked extended-cavity diode lasers at 1.39 μm. The method consists in the highly accurate observation of the shape of the 4(4,1)→4(4,0) line of the H2(18)O ν1+ν3 band, in a water vapor sample at thermodynamic equilibrium. A sophisticated and extremely refined spectral analysis procedure is adopted for the retrieval of the Doppler width as a function of the gas pressure, taking into account the Dicke narrowing effect, the speed dependence of relaxation rates, and the physical correlation between velocity-changing and dephasing collisions. A spectroscopic determination of the Boltzmann constant with a combined (type A and type B) uncertainty of 24 parts over 10(6) is reported. This is the best result obtained so far by means of an optical method. Our determination is in agreement with the recommended CODATA value.

In this work a longitudinally pumped, widely tunable, solid state Yb:YLF laser was developed with special design for applications to optical frequency metrology, LIDAR measurements in the atmosphere and for absolute frequency stabilization. The YLF crystalline host, combined with efficient diode pumping, allows for wide wavelength tunability at around 1.03 mum. The novel laser source is being thoroughly characterized in terms of output power, spatial beam quality, single frequency output, and wavelength tunability.

Subungual glomus tumours are rare benign hamartomas arising from the arterial end of the glomus body (an arteriovenous shunt related to thermoregulation). A combination of clinical examination, Color-Doppler ultrasonography and magnetic resonance imaging (MRI) is used to support the diagnosis confirmed by histology. A 45 year old male patient with a three-year-old swelling of the proximal thumbnail presented himself at the Surgery Department. A slightly bluish nail plate and tenderness under the thumbnail were evident at clinical examination. He suffered the classic trilogy of sensitivity to pain, pressure and temperature of the thumb lesion. Ultrasound and MRI revealed the presence of a small oval-shaped mass with hypervascularisation. All these elements reinforced the assumed diagnosis of a glomic tumour. The patient underwent excisional surgery under local anaesthesia. Histological examination confirmed a typical glomus tumour. Postoperative follow-up was uneventful and all symptoms disappeared immediately after surgery. Whenever a patient presents suffering from a reddish-purple, tender lesion, usually located at the extremities and especially in the nail bed, with paroxysmal pain and cold-sensitivity, a glomus tumour should be investigated. Surgical excision is the treatment of choice and is commonly resolutive.

Passive mode locking of a diode-pumped Yb3+:KYF4 laser is demonstrated using a semiconductor saturable absorber mirror. A high-stability, transform-limited pulse train with a repetition rate of 57 MHz is generated. Solitonlike pulses with maximum average output power of 250mW, minimum pulse duration of 170 fs, and rms time jitter of 360 fs were obtained.

Room-temperature continuous-wave laser action in a novel Tm-doped LiLuF4 crystal emitting at around 1.9 µm is demonstrated. The crystal growth process, spectroscopic measurements, and laser performance are presented for different Tm concentrations. An overall tunability extending from 1817 to 2056 nm, a slope efficiency of 46%, and a maximum output power in excess of 1.1 W are reported.

Frequency-modulation spectroscopy of the CH3D molecule is performed to assess a novel optical frequency standard at 1.54- m wavelength. Numerical integration of the demodulated first derivative signals provides the Voigt absorption profiles for the R(6,3) transition at 1543.78 nm at different gas pressures. Deconvolution with the Gaussian (Doppler) line provides the corresponding Lorentzian (collisional) line as a function of the gas pressure. Measurements of the collisional broadening contribution, at three different gas pressures, provide a collisional broadening coefficient of 37 MHz/kPa for the R(6,3) line.

A spectroscopic characterization of Tm-Ho:KYF4 crystals with different doping levels is presented. A comparative investigation based on diode-pumped 2-µm laser experiments shows that the best trade-off in terms of cw output power characteristics and wavelength tuning ranges is obtained with 5% Tm-0.5% Ho active crystal.PACS 42.55Xi; 42.55Rz; 42.60Pk; 42.70Hj; 42.60Lh

We report on the measurement of the nonlinear phase shift fNL induced by a strong pump at wavelength lp on a weak signal at ls through a cascade of two second-order interactions in a periodically-poled lithium-niobate waveguide. The experiment is performed by using an interferometric scheme especially designed to be insensitive to slow mechanical and thermal drift effects. The observed behavior of fNL as a function of the pump power and of the wavelength difference lp - ls is in good agreement with the theoretical predictions. OCIS codes: 190.4390, 190.2620, 130.2790, 130.3730.

Optical buffering of sub-nanosecond pulses at 1.55 µm in fibre Bragg gratings with periodically-spaced p phase shifts is demonstrated. Delays up to 690 ps of 250 ps-duration optical pulses have been achieved in a 40 cm-long grating with 100 phase jumps.

A novel BaY2F8 crystal doped with thulium ions is grown and extensively investigated. Owing to the large number of vibronic levels and to a favorable electron-phonon coupling, extremely wide absorption and emis-sion bands around 1.9 mm are observed. A room-temperature Tm: BaY2F8 laser tunable over a 210-nm in-terval, from 1849 to 2059 nm, is demonstrated.