Vitamin D deficiency is a recognized problem in Europe; this can be minimized by fortifying a broader range of foods. Our aim was to investigate the potential for enhancing the vitamin D content of pork from pigs raised in indoor facilities, by exposing the pigs to UVB for a period just before slaughter. Three groups of six pigs were exposed to 0, 0.7 or 1 SED/day for 28 days. A fourth group was exposed to 2 SED; this treatment was not completed due to mild erythema. The highest increase of vitamin D₃ was achieved with 1 SED; the vitamin D₃ content in loin was 3.7 ng/g; more than a factor of 2 higher compared to previously reported results from studies using 2000 IU/kg feed, the maximum allowed level in Europe. This is the first time an increase in the vitamin D content of pork has been reported as a result of using artificial UVB exposure of slaughter pigs in indoor facilities. However, the maximum production of vitamin D was probably not reached as a linear relationship between UVB dose and vitamin D content was found; therefore, the UVB-lighting method described still calls for further investigation to realise its full potential to enhance vitamin D in pork.

The concept of sensory delivery rooms was introduced in 2013. These rooms offer programmable calming lights, restful blurred pictures displayed on a wall-sized big screen, and sound effects. The primary aim of this observational study was to analyse the risk of obstetrical interventions among women giving birth for the first-time in a sensory delivery room vs. a standard delivery room. We included nulliparous, term pregnant women having a single baby with a cephalic presentation who were in spontaneous labour and gave birth between March 1^st 2014 and July 1^st 2015 in North Zealand Hospital, Hillerød. A total of 789 women were included in the study, 313 gave birth in a sensory room and 476 in a standard delivery room. The risk of a caesarean delivery was significantly decreased when giving birth in a sensory room compared with a standard delivery room (OR, multiple adjusted: 0.44; 95% CI 0.22–0.87); furthermore, the use of oxytocin infusion was also reduced (OR, multiple adjusted: 0.71; 95% CI 0.50–1.03). This observational cohort study suggests that giving birth in a sensory delivery room could lower the risk of caesarean delivery, potentially reducing the number of such deliveries by one for every 23 patients.

Tunable dual-wavelength operation of a diode laser system based on a tapered diode amplifier with double-Littrow external-cavity feedback is demonstrated around $800\mathrm{nm}$. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to $5.0\mathrm{THz}$. An output power of $1.54\mathrm{W}$ is achieved with a frequency difference of $0.86\mathrm{THz}$, the output power is higher than $1.3\mathrm{W}$ in the $5.0\mathrm{THz}$ range of frequency difference, and the amplified spontaneous emission intensity is more than $20\mathrm{dB}$ suppressed in the range of frequency difference. To our knowledge, this is the highest output power from a dual-wavelength diode laser system operating with tunable terahertz frequency difference.

Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M²-values of 1.8 (fast axis) and 3.3 (slow axis) match the M²- values of the laser with lowest spatial coherence. The principle of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future.

The effect of external feedback on the degradation of 808 nm emitting AlGaAs-based high-power broad-area diode lasers is studied. For this purpose, early stages of gradual degradation are induced by accelerated aging at high power levels. While the quantum well that actually experiences the highest total optical load remains unaffected, severe impact by point defects is observed on the cladding layers and the waveguide. Extended defects such as dislocations, however, are not observed in such early stages of degradation, which are accompanied by gradual power loss of a few percent only.

We present a theoretical analysis of the lateral modes of a broad-area semiconductor laser. The structure of the modes are classified into four categories and the modes are traced in the frequency versus pump rate diagram. It is shown how the branches of the frequency tuning curves for the different types of modes are interconnected and how the intensity profiles develop along the branches. The main result of the paper is the presentation of a small-signal stability analysis which identifies the saddle-node and Hopf bifurcation points on the mode tuning curves. For stable modes we derive expressions for small-signal noise and modulation spectra and present numerical examples of the spectra.