A time-distance helioseismic technique, similar to the one used by Ilonidis et al (2011), is applied two independent numerical models of subsurface sound-speed perturbations determine spatial resolution and accuracy phase travel time shift measurements. The technique also examine pre-emergence signatures several active regions observed Michelson Doppler Imager (MDI) Helioseismic Magnetic (HMI)....

We compare the performance of 10 and 5 μm thick metal–metal waveguide terahertz quantum-cascade laser ridges operating around 2.7 THz based on a 4-well phonon depopulation active region design. Thanks to reduced heat dissipation lower thermal resistance, material shows an 18 K increase in continuous wave temperature compared material, despite maximum pulsed-mode larger input power density. A 12...