Time-resolved orientation detection system with quantum cascade lasers.

A system with the combination of quantum cascade lasers (QCLs) and a photoelastic modulator (PEM) has been designed and constructed, which can achieve orientation detection with a time resolution of nearly 20 µs based on the principle of infrared dichroism, several orders of magnitude higher than that of the general mid-infrared spectrum. PEM with an inherent frequency of 50 kHz is employed to modulate the polarization direction of infrared light rapidly, the controller of which is used to provide the external trigger signal. A double frequency and delay circuit is fabricated to match the frequency of QCLs and PEM as well as overcome the delay during transfer of the trigger signal to a QCL controller, which can realize a minimum delay resolution of 5 ns.

Resonant absorption induced fast melting studied with mid-IR QCLs.

We demonstrate the use of a pump-probe setup based on two mid-infrared quantum cascade lasers (QCLs) to investigate the melting and crystallization of materials through resonant absorption. A combination of pump and probe beams fulfills the two-color synchronous detection. Furthermore, narrow linewidth advances the accuracy of measurements and the character of broad tuning range of QCLs enables wide applications in various sample and multiple structures.

Aldosterone down-regulates the slowly activated delayed rectifier potassium current in adult guinea pig cardiomyocytes.

Background And Purpose: There is emerging evidence that the mineralocorticoid hormone aldosterone is associated with arrhythmias in cardiovascular disease. However, the effect of aldosterone on the slowly activated delayed rectifier potassium current (IK s ) remains poorly understood. The present study was designed to investigate the modulation of IK s by aldosterone.