The fiber was fixed on a three-dimensional stage (Thorlabs PT3/M, resolution 2 ��m) through two fiber clamps (Thorlabs T711-250). A 3-g weight was hung on the fiber Enzalutamide molecular weight kinase inhibitor Crizotinib in order to maintain a constant stress in the fiber while the grating was being written. The small weight is important because the length is slightly increased when Inhibitors,Modulators,Libraries the fiber is melted by the laser. A CO2 laser (Synrad 48-2, wavelength 10.6 ��m) was focused on to the RHOF through a cylindrical lens, whose focal length was 10 cm. The laser illumination time was precisely controlled by a computer program. The fabrication process was monitored by a CCD camera through an angle of 45��.Figure 2.An illustration of the fabrication setup of the LPG written in the RHOF using a CO2 laser.
During Inhibitors,Modulators,Libraries the fabrication process, the laser power and Inhibitors,Modulators,Libraries illumination time were manually selected by virtually observing the thermal effect on the fiber, where only slight Inhibitors,Modulators,Libraries Inhibitors,Modulators,Libraries deformation induced by the heat from the laser pulses was observed through the CCD camera. The laser should induce sufficient change in refractive index but should Inhibitors,Modulators,Libraries not seriously weaken the fiber��s mechanical strength. Under the focusing by a 10-cm cylindrical lens, it was Inhibitors,Modulators,Libraries found that a suitable range was at 7% of the total power (25 W) and an illumination time of 3 s, such that LPGs can be successfully fabricated while maintaining sufficient their mechanical strength. Under the laser illumination at such conditions, the fiber was slightly melted, as seen from Figure 3.
When it solidified, due to the glass structure Inhibitors,Modulators,Libraries changes and physical deformation to the core and the cladding, a slight changein the effective refractive index was achieved.
After the deformation, the fiber was moved to the next point (one periodicity) by manually tuning the stage. Thus, the LPG was fabricated by a point-by-point technique, until Cilengitide Carfilzomib strong cladding mode couplings were observed in the optical spectrum analyzer.Figure 3.An optical micrograph of the deformation in the RHOF by the illumination of a CO2 laser. Such periodic deformations form the LPG, where �� denotes the grating periodicity.In the experiment, the cladding mode coupling was normally observed after a few periods and started to reach the maximum coupling efficiency very quickly.
selleck chemicals Calcitriol For example, a typical grating transmission spectrum with a periodicity of 450 ��m, is plotted. As it can be seen from Figure 4, the LPG reaches its maximum coupling efficiency of ?9.81 dB at the wavelength 1,498.5 nm with 14 periods. After reaching selleck chemicals the maximum coupling efficiency, the transmission dips were saturated, with no further change
Surface plasmon resonance (SPR) has been heavily utilized in optical bio-sensing applications, since its first development in 1983 by Liedberg et al. [1].