Homodyne Solid-State Biased Coherent Detection of Ultra-Broadband Terahertz Pulses with Static Electric Fields.

We present an innovative implementation of the solid-state-biased coherent detection (SSBCD) technique, which we have recently introduced for the reconstruction of both amplitude and phase of ultra-broadband terahertz pulses. In our previous works, the SSBCD method has been operated via a heterodyne scheme, which involves demanding square-wave voltage amplifiers, phase-locked to the THz pulse train, as well as an electronic circuit for the demodulation of the readout signal. Here, we demonstrate that the SSBCD technique can be operated via a very simple homodyne scheme, exploiting plain static bias voltages.

Cross-polarized photon-pair generation and bi-chromatically pumped optical parametric oscillation on a chip.

Nonlinear optical processes are one of the most important tools in modern optics with a broad spectrum of applications in, for example, frequency conversion, spectroscopy, signal processing and quantum optics. For practical and ultimately widespread implementation, on-chip devices compatible with electronic integrated circuit technology offer great advantages in terms of low cost, small footprint, high performance and low energy consumption. While many on-chip key components have been realized, to date polarization has not been fully exploited as a degree of freedom for integrated nonlinear devices.

[Value of transfontanelle echography in the diagnosis and surveillance of pericerebral effusions].

The authors report 3 cases of peri-cerebral fluid collection in infants. They emphasize the importance of anterior fontanelle real-time ultrasonography to set up the diagnosis and for the follow up of these patients. From a technical point of view they recommend the use of a water bag to facilitate the examination.

[Comparative study of computed x-ray tomography and saccoradiculography in the diagnosis of early lumbar disk herniation. Apropos of 50 surgically-proven cases].

Comparison of diagnostic accuracy using the two methods showed scanner imaging to provide superior results, with confirmation of herniated disc in 90 p. 100 cases based on purely discal semiological features. Limitations of the method result from the absence of epidural fat (narrow lumbar canals).