We present a theoretical interacting one-dimensional Bose-Einstein condensate (BEC) inside an optical cavity which is driven through of the fixed end mirrors. Under the Bogoliubov approximation and when the number of photons inside the cavity is not too large, the atomic field operator can be considered as a single-mode quantum field which is coupled to the radiation pressure of the intracavity field. In this way, the system behaves like an optomechanical system with an extra nonlinear term corresponding to the atom-atom interaction. We show that one of the best ways of tracing the effect of atomic interaction is to study the noise power spectrum of the field of the cavity. For this purpose, we study the light intensity spectrum of the cavity as well as the entanglement between the optical cavity and the BEC. We show how the pattern of the power spectrum of the cavity changes due to the nonlinear effect of atomic collisions. Furthermore, it is shown that due to the s-wave scattering frequency of the atom-atom interaction, one can measure the strength of interatomic interaction. Besides, we show how the atomic collisions affect the entanglement between subsystems and cooling behavior of the BEC atoms.

In this research, we try to improve the performance of ultraviolet (UV) photodetector based on ZnO nanorods through decoration with Au nanoparticles. One-dimensional ZnO nanorods were grown on the quartz substrates by the vapor phase transport (VPT) method. Then, Au nanoparticles by depositing a thin nanometric Au layer with thicknesses 3, 6, 9, and 12 nm via sputtering technique and a heating process were coated on the ZnO nanorods. The morphology and structure of the samples were characterized by using a Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD). The results showed formation of rather aligned ZnO nanorods with wurtzite hexagonal crystalline structure and preferred orientation along the c-axis which are coated with Au nanoparticles. The obtained data from measuring ultraviolet photoresponse shows that the decorated sample with 9 nm thick Au film possesses a higher on/off ratio (6. 5), responsivity (568 ± 33 mA/W), and faster rise and decay times. In addition, with presence of Au nanoparticles, responsivity in the visible region (λ= 520 nm) increased from 6 ±0. 5 mA/W to 19±1 mA/W. This improved detecting behavior results from Localized Surface Plasmons (LSPs) of the Au nanoparticles and the formation of localized Schottky barriers between Au nanoparticles and ZnO.