Investigation of TE and TM polarised laser emission in GaInP/AlGaInP lasers by growth-controlled strain

GaInP/AlGaInP double heterostructure lasers can be obtained with either TE or TM polarised emission. In addition it it shown that, by using appropriate samples, TE or TM lasing can be selected by changing the temperature or the cavity length.<>     

Reactions of Podophyllotoxin with DDQ

Introduction 2, 3-Dichloro-5, 6-dicyanobenzoquinone (DDQ) can react with lignans of the mono- arylidene-butyrolactone1, aryltetralin2, dibenzylbutane3 and aryltetralin-butyrolactone4,5 series. We have studied the reactions of this reagent with podophyllotoxin 1, which is a well-known natural product on account of its long history of use in folk medicine and the biological activity of its many derivatives6. In particular, derivatives of 4-demethyl epipodophyllotoxin are used in cancer chemo…     

Assessing the placement of a cochlear electrode array by multidimensional scaling

Correct placement of the electrode is crucial for cochlear implantation (CI) surgery. It determines the access to the auditory nerve and subsequent hearing performance. Here, we propose an objective measures tool that can partially verify the electrode position. The intracochlear spread of the electrical fields is measured and analyzed by means of multidimensional scaling resulting in an intuitive visual representation. The user can then detect major issues, such as electrode foldover or ossification. Other implantation issues, such as electrode migration into the scala vestibuli, may not significantly alter the electrical conduction pattern and remain undetected. Still, as the measurement is quick and readily available, it may be a valuable intraoperative verification tool.     

High-power 1.06 mu m GaInAsP DCPBH lasers

High-power 1.06 mu m double channel planar buried-heterostructure (DCPBH) lasers have been fabricated by liquid-phase epitaxy. AT 20 degrees C, the threshold current is 80 mA and CW output powers of 20 mW can be obtained. Under pulsed operation, quantum efficiencies of 0.37 W/A per facet and maximum pulse output powers of 150 mW are realised, while maintaining the lowest-order spatial mode and a symmetrical far-field distribution.<>