A power detection system implemented using a pair of directional couplers and a transmission line disposed between the directional couplers, wherein the transmission line provides a 90\xb0 phase shift between the directional couplers. In some embodiments, an audio headset that includes one or more electroencephalography sensors is provided. The recognizing module recognizes a trigger event at a client of the data storage system. Preferably, the coating layer is substantially index matched to the readout surface layer. In certain embodiments, the genetically modified photosynthetic microorganisms also contain one or more exogenous genes encoding a diacyglycerol acyltransferase, a phosphatidate phosphatase, andor an acetyl-CoA carboxylase, and which are capable of producing increased amounts of lipids or fatty acids andor synthesizing triglycerides.