Research On Properties Of Ultra-high Mode Of Metal-cladding Waveguide In MIR Region

In the recent years, the research of the integrated optics has extended to mid-infrared region from near-infrared and properties of mid-infrared waveguide and relevant applications have been a hotspot of MIR research. The ultra-high modes activated by metal-cladding waveguide in MIR region have high sensibility on wavelength, thickness and refractive index and have effective negative GH shift enhancement effect in the meanwhile. Therefore, research on the properties of ultra-high mode and utilize it to realize sensors or filter. It has great application prospect in environmental monitoring, water monitoring and material analysis.In the background mentioned above, we proposed several kinds of mid-infrared sensors based on ultra-high modes and realized them by experiment methods. The main work of this thesis can be summarized as follows:1. We analyzed the mode theory of metal-cladding waveguide by plugging the dielectric constants of metal into intrinsic equation of planar waveguide. We found the effective refractive index of the ultra-high mode is close to 0 when the thickness of waveguide layer is enhanced to millimeter magnitude. The ultra-high modes have high sensibility to thickness, wavelength and refractive index. We realized sensors by monitoring the absorption spectrum.2. Depend on experiment requirement, we designed MIR prism and build the experimental system in 5.4μm. After evaporating silver film on mid-infrared prism and waveguides by electron beam evaporation and thermal evaporation, we did several times of test on mid-infrared sensors we designed to analyze properties of ultra-high mode. The result of the experiment has been contrasted to result in theory and we also proposed improvement methods after analyzing merit and demerit of the sensors.3. We analyzed the effective negative GH shift enhancement of ultra-high mode and found large negative beam shift in mid-infrared region. The relationship between effective negative shift and waveguide parameters has been discussed and designed a ’light trap’ in free space and a controllable light delay device based on metal-cladding waveguide of millimeter magnitude.