- Figure 1: Angular reflectance spectra for a 49 nm thin gold film surrounded by index-matching gel and air.
Surface Plasmon Resonance Sensor
Setfos can be used to study the surface plasmon resonances in thin film devices. An example of an angular reflectance calculation for a biosensor device is given in Figure 1. Setfos simulation results were published by Frischeisen et al., Optics Express, Vol.16, No. 22, (2008).
- Figure 1: Multilayer passive optics element.
Multilayer Spectral Filter and Mirrors
Thanks to interference effects, refractive multilayered thin films can be designed in order to transmit, reflect, absorb a certain region of the incident spectrum, depending on the incidence or observation angle. Let's suppose to have a stack as depicted in Figure 1.
- Figure 2: The reflected spectrum of a multilayered refractive element at zero observation spectrum. In this case, the polarization state of the light wave does not play any decisive role.
Then, for a given pair of high and low refractive index materials, and a fixed layer thickness, the reflected intensity at normal observation (0°) for white incident light looks as depicted in Figure 2.
Depending on the application, it might be interesting to enhance the reflection of certain colors in a given direction rather than another. In this case, setfos helps the engineer in simulating the appropriate multilayer combination prior to waste time and resources in chaotic trial&error experiments.
- Figure 3 Reflection characteristics of a multilayer optics stack as depicted in Figure 1 for 30°-observation angle.
- Figure 4 Reflection characteristics of a multilayer optics stack as depicted in Figure 1 for 60°-observation angle. At observation angles different than 0°, the polarization state of the light wave (p or s) plays a more and more important role.
