An optically activated cantilever using photomechanical effects in dye-doped polymer fibers

We report on what we believe is the first demonstration of an optically activated cantilever due to photomechanical effects in a dye-doped polymer optical fiber. The fiber is observed to bend when light is launched off-axis. The displacement angle monotonically increases as a function of the distance between the illumination point and the fiber axis, and is consistent with differential light-induced length changes. The photothermal and photo-reorientation mechanisms, each with its own distinct response time, are proposed to explain the observed time dependence. The measured degree of bending is consistent with a model that we have proposed which includes coupling between photoisomerization and heating. Most importantly, we have discovered that at high light intensity, a cooperative release of stress results in cis-to-trans isomerization that yields a large and abrupt length change.Comment: 13 pages, 16 figure

Photorefractive Response Time Measurement In Gaas Crystals By Phase Modulation In Two-wave Mixing

The possibility of using phase-modulation techniques in two-wave mixing (2 WM) experiments for response time measurement in fast materials such as GaAs is shown in the study. The main idea here is that a small phase modulation in one of the interfering beams makes the interference pattern on the crystal vibrate with the modulation frequency. The modulation technique described here is similar to that reported for photoelectromotive-force measurement in photoconductors.19211702170

Stationary Measurement Of The Response Time In Reversible Optical Recording Materials

We report a steady-state continuous technique for the measurement of the response-time in reversible optical recording materials. This method is based on phase modulation and homodyne detection techniques and is particularly suited for fast materials. Experiment is carried out using an undoped semi-insulating GaAs crystal.146647