Electrically Switchable Photonic Molecule Laser

We have studied the coherent intercavity coupling of the evanescent fields of the whispering gallery modes of two terahertz quantum-cascade lasers implemented as microdisk cavities. The electrically pumped single-mode operating microcavities allow to electrically control the coherent mode coupling for proximity distances of the cavities up to 30-40 \mu\m. The optical emission of the strongest coupled photonic molecule can be perfectly switched by the electrical modulation of only one of the coupled microdisks. The threshold characteristics of the strongest coupled photonic molecule demonstrates the linear dependence of the gain of a quantum-cascade laser on the applied electric field.Comment: 4 pages, 4 figure

Dysfunction of Mitral Ball Valve Prosthesis

Three case histories of patients with malfunctions of Smeloff-Cutter mitral ball valve prostheses are presented here - one underwent successful replacement. The clinical diagnosis was made by observing a marked variation in the A2OC interval and intermittent absence of the opening click. Phonocardiograms were diagnostic in all three cases. while echocardiograms and even angiograms did not uniformly diagnose prosthetic valve dysfunction. Periodic phonocardiographic evaluations may be helpful in early detection of the prosthetic valve dysfunction. Once the diagnosis is established, immediate surgical treatment is imperative to prevent sudden death