Abstract: An exemplary refractive-index sensor includes a photonic crystal microcavity structure, a light source, and a detector. The photonic crystal microcavity structure includes a photonic crystal layer having first holes and a second hole defined therein. The first holes are arranged in a regular pattern of staggered parallel rows. The second hole is at an approximate center of the regular pattern, instead of a first hole. A diameter of the second hole is different from that of the first holes. The first holes at each of opposite ends of the row having the second hole are omitted, thereby defining an input waveguide and an output waveguide. The light source is adjacent to the input waveguide. The detector is adjacent to the output waveguide.

Abstract: A light emitting diode includes a substrate, a reflecting layer, an active layer, a transparent electrode, a first photonic crystal structure, and a second photonic crystal structure. The reflecting layer is disposed on the substrate. The active layer is disposed on the reflecting layer. The transparent electrode is disposed on the active layer and includes an upper surface and a lower surface. The lower surface of the transparent electrode combines with the active layer. The first photonic crystal structure is formed on the upper surface of the transparent electrode. The second photonic crystal structure formed in the active layer.

Abstract: A micro displacement sensor includes a first photonic crystal module, a second photonic crystal module, a light source and a detector. The first photonic crystal module includes a first substrate and a plurality of first photonic crystals, disposed on the first substrate and are arranged in a matrix. The first photonic crystals define a first light-guide channel having a light input end and a light output end. The second photonic crystal module includes a second substrate, disposed parallel to the first substrate, and a plurality of second photonic crystals, disposed on the second substrate and are arranged in a matrix. The second photonic crystals define a second light-guide channel having a light coupling end and a light detected end. The light source is disposed adjacent to the light input end. The detector is disposed adjacent to the light detected end.

Abstract: An exemplary refractive-index sensor includes a photonic crystal microcavity structure, a light source, and a detector. The photonic crystal microcavity structure includes a photonic crystal layer having first holes and a second hole defined therein. The first holes are arranged in a regular pattern of staggered parallel rows. The second hole is at an approximate center of the regular pattern, instead of a first hole. A diameter of the second hole is different from that of the first holes. The first holes at each of opposite ends of the row having the second hole are omitted, thereby defining an input waveguide and an output waveguide. The light source is adjacent to the input waveguide. The detector is adjacent to the output waveguide.

Abstract: A method for measuring micro displacements generally includes the steps of: (a) providing a micro displacement sensor with a first photonic crystal module with a number of first crystals, a second photonic crystal module with a number of second crystals, a laser, and a detector; the first crystal module and the second crystal module having a first light guide channel and a second light guide channel therein, respectively; (b) securing the second crystal module onto a sample, the first channel and the second channel being optically coupled together; and (c) during operation, emitting light from the laser, directing such light into the first channel, a first portion of the light exiting from the first channel and a second portion of the light entering the second channel, and analyzing a “light intensity vs. displacement” sine curve to obtain a horizontal micro displacement of the sample.

Abstract: A light emitting diode includes a substrate, a reflecting layer, an active layer, a transparent electrode, a first photonic crystal structure, and a second photonic crystal structure. The reflecting layer is disposed on the substrate. The active layer is disposed on the reflecting layer. The transparent electrode is disposed on the active layer and includes an upper surface and a lower surface. The lower surface of the transparent electrode combines with the active layer. The first photonic crystal structure is formed on the upper surface of the transparent electrode. The second photonic crystal structure formed in the active layer.

Abstract: A light-emitting diode includes a substrate (110), a reflective layer (120), a second diffraction grating (130), a first semiconductor layer (142), an active layer (144), a second semiconductor layer (146), a transparent electrode layer (148), and a first diffraction grating (150), arranged in that order. The first diffraction grating and the second diffraction grating is composed of an array of parallel and equidistant grooves, and a inclined angle between the grooves of the first diffraction grating and the grooves of the second diffraction grating is equal to or more than 0° and equal to or less than 90°. One of the first semiconductor layer and the second semiconductor layer is an N-type semiconductor and the other thereof is a P-type semiconductor. The light-emitting diode has high light extraction efficiency and is easy to manufacture at a low cost.

Abstract: A method for measuring micro displacements generally includes the steps of: (a) providing a micro displacement sensor with a first photonic crystal module with a number of first crystals, a second photonic crystal module with a number of second crystals, a laser, and a detector; the first crystal module and the second crystal module having a first light guide channel and a second light guide channel therein, respectively; (b) securing the second crystal module onto a sample, the first channel and the second channel being optically coupled together; and (c) during operation, emitting light from the laser, directing such light into the first channel, a first portion of the light exiting from the first channel and a second portion of the light entering the second channel, and analyzing a “light intensity vs. displacement” sine curve to obtain a horizontal micro displacement of the sample.

Abstract: A micro displacement sensor includes a first photonic crystal module, a second photonic crystal module, a light source and a detector. The first photonic crystal module includes a first substrate and a plurality of first photonic crystals, disposed on the first substrate and are arranged in a matrix. The first photonic crystals define a first light-guide channel having a light input end and a light output end. The second photonic crystal module includes a second substrate, disposed parallel to the first substrate, and a plurality of second photonic crystals, disposed on the second substrate and are arranged in a matrix. The second photonic crystals define a second light-guide channel having a light coupling end and a light detected end. The light source is disposed adjacent to the light input end. The detector is disposed adjacent to the light detected end.