Current Issue : October - December Volume : 2012 Issue Number : 4 Articles : 5 Articles
Terahertz frequencies experiments has motivated the development of new sources, detectors and optical components. Here we will\r\npresent a review of THz bandpass filters ranging from 0.4 to 10 THz. We also demonstrate our fabrication process, simulations\r\nand experimental results....
Since its introduction, optical coherence tomography (OCT) technology has advanced dramatically in various field of both clinical\r\nand fundamental research. Full-field and Single-shot full-field OCT (FF-OCT and SS-FF-OCT) are alternative OCT concepts,\r\nwhich aims to improve the image acquisition speed and to simplify the optical setup of conventional point-scan OCT by realizing\r\ndirect line field or full-field sample imaging onto an array or line detector such as CCD or CMOS camera. FF-OCT and SS-FFOCT\r\nare based on bulk optics Linnik-type Michelson interferometer with relatively high numerical aperture (NA) microscopic\r\nobjectives. This paper will give you an overview of the principle of various types of FF-OCT and SS-FF-OCT techniques and its\r\nassociated system design concept and image reconstruction algorithms...
We present the performance of a laser prototype based on 1% at. Yb : Lu2O3 ceramic, longitudinally pumped in quasi-CW regime\r\nat 968 nm. A slope efficiency of 49% with respect to the absorbed pump power was obtained for laser operation at 1032.5 nm.We\r\nstudied the effects on the laser oscillation due to the reinjection of the residual pump. The thermal behavior of the sample was\r\ninvestigated by means of numerical simulations, accounting for the different thermal load resulting from spontaneous and laser\r\nemission. Finally, we report the measured level of the Amplified Spontaneous Emission, which is found to be less than 0.1mW....
Vertical-cavity surface-emitting lasers (VCSELs) yield single-longitudinal-mode operation, low-divergence circular output beam,\r\nand low threshold current. This paper gives an overview on theoretical, self-consistent modelling of physical phenomena occurring\r\nin a VCSEL. The model has been experimentally confirmed. We present versatile numerical methods for nitride, arsenide, and\r\nphosphide VCSELs emitting light at wavelengths varying from violet to near infrared.We also discuss different designs with respect\r\nto optical confinement: gain guidance using tunnel junctions and index guidance using oxide confinement or photonic crystal and\r\nwe focus on the problem of single-transverse-mode operation....
In a previous work, we described the simulation tool (FOPS 3D) (Khankin et al., 2001) which can simulate the full three-dimensional\r\ngeometrical structure of a fiber and the propagation of a light beam sent through it. In this paper we are focusing on three\r\nmajor points: the first concerns the improvements made with respect to the simulation tool and the second, optimizations implemented\r\nwith respect to the calculations� efficiency. Finally, the major research improvement from our previous works is the\r\nsimulation results of the optimal absorbance value, as a function of bending angle for a given uncladded part diameter, that\r\nare presented; it is suggested that fiber-bending may improve the efficiency of recording the relevant measurements. This is the\r\nthird iteration of the FOPS development process (Mann et al., 2009) which was significantly optimized by decreasing memory\r\nusage and increasing CPU utilization....
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