Abstract: This invention relates to an optical pickup for a musical instrument based on one or more than one Bragg grating. In one embodiment the optical pickup includes at least one Bragg grating in physical contact with a vibrating structure of the musical instrument so as to receive acoustic vibration associated with the musical instrument being played, such that a spectrum of the Bragg grating is modulated upon receipt of the acoustic vibration. A light signal reflected from the at least one Bragg grating may be amplified and the output may be directed to a loud speaker or other real-time output device. The output may also be directed to a data acquisition system for storage and further processing. The optical pickup may include two Bragg gratings arranged as an optical cavity.

Abstract: The invention relates to optical sensors and systems and methods employing the sensors for detecting one or more compounds of interest in a test medium. In one embodiment an optical sensor comprising a long period grating and a solid phase microextraction (SPME) film is exposed to a test medium such that one or more compounds of interest are selectively partitioned into the solid phase microextraction film. At least one optical property of the sensor exposed to the test medium is compared with at least one corresponding optical property of the sensor in absence of the test medium; wherein a difference in the optical property is indicative of one or more compounds of interest in the test medium. The methods and systems may employ long period grating sensors with or without SPME films, and fiber loop ring-down spectroscopy to measure optical properties of the sensor.