A multi-active-region bipolar-cascade edge-emitting laser emitting at nearly 900 nm is presented. The three active regions and two tunnel junctions located in a single waveguide core share the same third-order vertical mode. A slope efficiency of 3.6 W/A was measured with a threshold current density of 230 A/cm 2 . The epitaxial layer stack developed features with very low internal optical losses of 0.7 cm −1 . The voltage extrapolated to vanishing current is only 0.3 V larger than 3 times the voltage of 1.4 V originating from the photon energy.

We present a multi‐active‐region bipolar‐cascade distributed‐Bragg reflector (DBR) laser emitting around 910 nm. The three active regions and two tunnel junctions are located in a single waveguide core sharing the same third‐order vertical mode. A slope efficiency of 2.25 W/A was measured with a threshold current density of 400 A/cm2. Due to the implemented 7th Bragg order surface grating, the laser exhibits a narrow optical spectrum with a width of 0.3 nm and a thermal detuning of 60 pm/K.

Background: Knowledge and attitude towards organ donation are critical factors influencing organ donation rate. We aimed to assess the knowledge and attitude towards organ donation in adolescents in Austria and Switzerland. Methods: A paper-based survey was performed in two secondary schools (age range 11-20 years) in Austria and Switzerland. 354/400 surveys were sufficiently answered and analyzed. Results: Our study found that knowledge on organ donation is scarce in adolescents. Less than 60% of those surveyed thinks that a person is dead when declared brain dead. 84.6% would authorize organ donation after brain death for themselves, but only 69% would authorize organ donation after brain death for a close relative. 93.7% would accept a donor organ if they needed one. Family discussions, rather than school discussions, influenced knowledge on organ donation, the percentage of respondents who have a firm opinion on organ donation and the rate of declaration of this opinion. Age, gender, nationality and religion also influenced knowledge and attitude towards organ donation. Nearly one third of adolescents are of the opinion that selling non-vital organs should be legalized. Conclusion: Since having had family discussions, a potentially modifiable factor, was positively associated with knowledge and attitude towards organ donation, we postulate that educational programs stimulating family discussions on organ donation may be a promising strategy to increase knowledge.

The emission characteristics of a novel, specially designed broad area diode laser (BAL) with on-chip transversal Bragg resonance (TBR) grating in lateral direction were investigated in an off-axis external cavity setup. The internal TBR grating defines a low loss transversal mode at a specific angle of incidence and a certain wavelength. By providing feedback at this specific angle with an external mirror, it is possible to select this low loss transverse mode and stabilize the BAL. Near diffraction limited emission with an almost single lobed far field pattern could be realized, in contrast to the double lobed far field pattern of similar setups using standard BALs or phase-locked diode laser arrays. Furthermore, we could achieve a narrow bandwidth emission with a simplified setup without external frequency selective elements.

An external volume Bragg grating (VBG) is used for transverse and longitudinal mode stabilization of a broad area diode laser (BAL) with an on-chip transverse Bragg resonance (TBR) grating. The internal TBR grating defines a transverse low-loss mode at a specific propagation angle inside the BAL. Selection of the TBR mode was realized via the angular geometry of an external resonator assembly consisting of the TBR BAL and a feedback element. A feedback mirror provides near diffraction limited and spectral narrow output in the TBR mode albeit requiring an intricate alignment procedure. If feedback is provided via a VBG, adjustment proves to be far less critical and higher output powers were achieved. Moreover, additional modulation in the far field distribution became discernible allowing for a better study of the TBR concept.