Laser remote sensing represents a powerful tool that enables the accurate measurement of the speed of moving targets. Crucially, most sensing techniques are 2-Dimensional in nature and do not enable direct determination of the full velocity vector of objects moving in 3D. A disadvantage that is very often compensated with two-dimensional techniques that in many cases are hard to implement and in others, require complicated postprocessing analysis. Here we demonstrate a novel technique that enables the direct and simultaneous measurement of both velocity components using a single interrogating beam. This technique is based on the use of complex light beams, whose polarization and spatial degree of freedom are coupled in a non-separable way. We present experimental results of a proof-of-principle experiment by applying our technique to the specific case of helical motion, of great relevance in a wide of research areas.
A novel liquid-level sensing system based on differential pulse-width pair Brillouin optical time domain analysis technology with a self-heated high attenuation fiber (HAF) is proposed and demonstrated in this paper, where the principle is to measure the temperature abruption position at the interface between liquid and air caused by the different thermal diffusion rates of the two kinds of mediums. The sensing optical fiber was glued to a 1-m HAF with an absorption coefficient of 20 dB/m, so that heat can be transmitted from the HAF to the sensing fiber through physical contact, which will cause temperature increase of the latter. The Brillouin frequency shift (BFS) profiles of the sensing fiber when the HAF was heated by different heating optical powers were characterized to find out the optimized heating power. The BFS distributions were measured for different water levels, with the result indicating that liquid-level sensing with a range of 20 cm and a resolution of 1 cm is realized.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.