3 results for “Shahram Mohammad Nejad”

Research ArticleOpen accessIn the author namesOptimal Dark Current Reduction in Quantum Well 9 µm GaAs/AlGaAs Infrared Photodetectors with Improved DetectivityShahram Mohammad Nejad, Saeed Olyaee, Maryam PourmahyabadiIn this research, an optimization approach is presented to decrease the dark current in GaAs/AlGaAs QWIPs. The dark current noise is reduced by increasing Al density in barriers, decreasing detector dimensions and increasing the periodic length of the structure. In addition, increasing the number of periods can reduce both the dark current and responsivity. Therefore, devices can be optimally designed … …American Journal of Applied Sciences, Vol. 5, Issue 8 · 31 Aug 2008 · 7,188 accessesView PDF Cite

Research ArticleOpen accessIn the author namesLow-Noise High-Accuracy TOF Laser Range FinderShahram Mohammad Nejad, Saeed OlyaeeThis paper presents a new low-noise high-accuracy laser range finder based on the Time-Of-Flight (TOF) method. A Q-switched Nd:YAG laser at 1064 nm as a source and a SLIK avalanche photodiode as a detector are used. The optical section of the system including ZnS/MgF2 optical filter, designed by C++ and Zemax software, has been successfully implemented and tested. The quality … …American Journal of Applied Sciences, Vol. 5, Issue 7 · 31 Jul 2008 · 7,849 accessesView PDF Cite