Photonic Crystal Supporting High Frequency Sensitivity Self-collimation Phenomenon and Design Method and Use thereof

A design method for the photonic crystal supporting high frequency sensitivity self-collimation phenomenon, characterized in that, the design method for the photonic crystal supporting high frequency sensitivity self-collimation phenomenon at least includes:

• a) Based on the types of crystal lattice, material and structural parameters of the photonic crystal, calculating the dispersion relation of the photonic crystal, so as to form equi-frequency contours and to determine a candidate photonic crystal that exists a self-collimation point and one or more van Hove singularities inside the Brillouin zone within the same band, the material parameter of the photonic crystal comprises refractive indexes of various materials that constitutes the photonic crystal, the structural parameter of the photonic crystal comprises shapes and sizes of various materials that constitutes the photonic crystal and lattice lengths of each directions thereof, the types of the van Hove singularities inside the Brillouin zone comprises one or more of saddle-point-type van Hove singularities, a maximum-point-type van Hove singularities and minimum-point-type van Hove singularities;
• b) Change each material and structural parameter of the candidate photonic crystal, recalculating the dispersion relation to form equi-frequency contours and to determine the key parameter of the photonic crystal, wherein, the key parameter of the photonic crystal refers to, the material and/or structural parameter of the photonic crystal as its value changes, it enables the van Hove singularities move close to or away from the self-collimation point;
• c) Based on the dispersion relation around the self-collimation point, determining the distribution of the self-collimation frequency sensitivity γ with the key parameter of the photonic crystal;
• d) Selecting a required self-collimation frequency sensitivity determining the value of the key parameter of the photonic crystal and the value of other structural and material parameters of the photonic crystal according to the distribution of the self-collimation frequency sensitivity with the key parameter of the photonic crystal.

A method for detecting refractive index based on a photonic crystal supporting high frequency sensitivity self-collimation phenomenon, characterized in that, the method for detecting refractive index based on a photonic crystal supporting high frequency sensitivity self-collimation phenomenon at least comprises the following steps:

• 1) Providing a piece of photonic crystal supporting high frequency sensitivity self-collimation phenomenon, a light source placed at one side of the photonic crystal and a light intensity detector arranged at the other side of the photonic crystal being opposite to the light source;
• wherein, there are interspaces of periodic configuration inside the photonic crystal;
• the light source enables to generate a light beam with specific frequency, width and intensity along with the incident direction of the self-collimation;
• the light intensity detector is used for detecting a centre intensity of the light beam that emits from the photonic crystal;
• 2) The interspaces of periodic configuration inside the photonic crystal are filled with multiple materials of known refractive indexes, respectively, to form each first filled photonic crystal;
• 3) Making a light beam launch into each first filled photonic crystal, and detecting a centre intensity of outgoing beam corresponding to each refractive index, so as to determine the relationship between each refractive index and the intensity of the outgoing beam;
• 4) Filling the photonic crystal with sample to be tested, to form a second filled photonic crystal;
• 5) Making a light beam launch into the second filled photonic crystal, and determining the refractive index of the sample to be tested based on the measured centre intensity of outgoing beam, and the relationship between the refractive index and the intensity of the outgoing beam.