Abstract: An acoustic wave device includes a piezoelectric substrate including a crystal axis and an IDT electrode. When an acoustic wave propagation direction is a first direction and a direction perpendicular to the first direction is a second direction, the crystal axis of the piezoelectric substrate is inclined toward the second direction with respect to the thickness direction. The IDT electrode includes first and second electrode fingers interdigitated with each other. The portion where the first and second electrode fingers overlap in the first direction is a crossing region. The crossing region includes a center region that is centrally located in the second direction and first and second low-acoustic-velocity regions that are located on both sides of the center region in the second direction and in which the acoustic velocity is lower than the acoustic velocity in the center region. The first and second low-acoustic-velocity regions are asymmetrical.

Abstract: An acoustic wave device includes a piezoelectric substrate, and an IDT electrode provided on the piezoelectric substrate. The IDT electrode includes an overlap region where first and second electrode fingers overlap each other in a first direction. The overlap region includes a central region located in a substantially central portion of the overlap region with respect to a second direction. The central region includes a low acoustic velocity portion with an acoustic velocity less than the acoustic velocity in another portion. The overlap region includes first and second low acoustic velocity regions. The first and second low acoustic velocity regions are respectively located on first-and-second-busbar sides from the central region. The IDT electrode includes first and second high acoustic velocity regions. The first and second high acoustic velocity regions are respectively located outside the first and second low acoustic velocity regions with respect to the second direction.

Abstract: An acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate and includes a main electrode layer. In the IDT electrode, a central region, first and second low acoustic velocity regions and first and second high acoustic velocity regions are disposed in this order. A duty ratio in the first low acoustic velocity region of first electrode fingers and the second low acoustic velocity region of second electrode fingers is larger than a duty ratio in the central region. The main electrode layer includes any one of Au, Pt, Ta, Cu, Ni, and Mo as a main component.

Abstract: An acoustic wave device includes an acoustic wave resonator and a longitudinally coupled acoustic wave resonator filter, in which the longitudinally coupled acoustic wave resonator filter is shorter than the acoustic wave resonator in terms of a length of first and second edge regions that is a dimension along an extending direction of electrode fingers of the first and second edge regions in an IDT electrode.

Abstract: An acoustic wave device includes a piezoelectric substrate including a crystal axis and an IDT electrode. When an acoustic wave propagation direction is a first direction and a direction perpendicular to the first direction is a second direction, the crystal axis of the piezoelectric substrate is inclined toward the second direction with respect to the thickness direction. The IDT electrode includes first and second electrode fingers interdigitated with each other. The portion where the first and second electrode fingers overlap in the first direction is a crossing region. The crossing region includes a center region that is centrally located in the second direction and first and second low-acoustic-velocity regions that are located on both sides of the center region in the second direction and in which the acoustic velocity is lower than the acoustic velocity in the center region. The first and second low-acoustic-velocity regions are asymmetrical.

Abstract: An acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate and includes a main electrode layer. In the IDT electrode, a central region, first and second low acoustic velocity regions and first and second high acoustic velocity regions are disposed in this order. A duty ratio in the first low acoustic velocity region of first electrode fingers and the second low acoustic velocity region of second electrode fingers is larger than a duty ratio in the central region. The main electrode layer includes any one of Au, Pt, Ta, Cu, Ni, and Mo as a main component.

Abstract: An acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate. In the IDT electrode, a central region, first and second low acoustic velocity regions and first and second high acoustic velocity regions are disposed in this order. A duty ratio in the first low acoustic velocity region of first electrode fingers and the second low acoustic velocity region of second electrode fingers is larger than a duty ratio in the central region. When acoustic velocity of a transversal bulk wave propagating in metal that is a main component of a main electrode layer is defined as v (m/s), v?3299 m/s, and when a wave length defined by an electrode finger pitch of the IDT electrode is defined as ?, and a film thickness of the main electrode layer normalized by the wave length ? is defined as T, then T?0.00018e0.002V+0.014.

Abstract: An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and two reflectors on both sides of the interdigital transducer electrode in an acoustic wave propagation direction. The reflectors include first and second busbars and first to third electrode fingers, respectively, and the first and second busbars are opposed to one another. The first busbars and the second busbars are connected by at least one third electrode finger. The reflectors each include a center area located centrally in a length direction and a first high-acoustic-velocity area that is located between the center area and the first busbars and has an acoustic velocity higher than the acoustic velocity of the center area, where the length direction is a direction in which the first to third electrode fingers extend.

Abstract: A longitudinally coupled resonator acoustic wave filter includes first, second, and third IDT electrodes disposed on a piezoelectric substrate. The first, second, and third IDT electrodes include first electrode fingers and second electrode fingers. The first, second, and third IDT electrodes include narrow-pitch electrode finger portions in which the pitch between electrode fingers is narrower than in the remaining electrode finger portions. In the first, second, and third IDT electrodes, an overlap area includes a central area and first and second edge areas at opposite ends of the central area in the direction in which the first and second electrode fingers extend. In the remaining electrode finger portions the first electrode fingers and the second electrode fingers include wide portions in the first or second edge area.

Abstract: An acoustic wave device includes a piezoelectric substrate, and an IDT electrode provided on the piezoelectric substrate. The IDT electrode includes an overlap region where first and second electrode fingers overlap each other in a first direction. The overlap region includes a central region located in a substantially central portion of the overlap region with respect to a second direction. The central region includes a low acoustic velocity portion with an acoustic velocity less than the acoustic velocity in another portion. The overlap region includes first and second low acoustic velocity regions. The first and second low acoustic velocity regions are respectively located on first- and-second-busbar sides from the central region. The IDT electrode includes first and second high acoustic velocity regions. The first and second high acoustic velocity regions are respectively located outside the first and second low acoustic velocity regions with respect to the second direction.

Abstract: An acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate. In the IDT electrode, a central region, first and second low acoustic velocity regions and first and second high acoustic velocity regions are disposed in this order. A duty ratio in the first low acoustic velocity region of first electrode fingers and the second low acoustic velocity region of second electrode fingers is larger than a duty ratio in the central region. When acoustic velocity of a transversal bulk wave propagating in metal that is a main component of a main electrode layer is defined as v (m/s), v?3299 m/s, and when a wave length defined by an electrode finger pitch of the IDT electrode is defined as ?, and a film thickness of the main electrode layer normalized by the wave length ? is defined as T, then T?0.00018e0.002V+0.014.

Abstract: A longitudinally coupled resonator acoustic wave filter includes first, second, and third IDT electrodes disposed on a piezoelectric substrate. The first, second, and third IDT electrodes include first electrode fingers and second electrode fingers. The first, second, and third IDT electrodes include narrow-pitch electrode finger portions in which the pitch between electrode fingers is narrower than in the remaining electrode finger portions. In the first, second, and third IDT electrodes, an overlap area includes a central area and first and second edge areas at opposite ends of the central area in the direction in which the first and second electrode fingers extend. In the remaining electrode finger portions the first electrode fingers and the second electrode fingers include wide portions in the first or second edge area.

Abstract: An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and two reflectors on both sides of the interdigital transducer electrode in an acoustic wave propagation direction. The reflectors include first and second busbars and first to third electrode fingers, respectively, and the first and second busbars are opposed to one another. The first busbars and the second busbars are connected by at least one third electrode finger. The reflectors each include a center area located centrally in a length direction and a first high-acoustic-velocity area that is located between the center area and the first busbars and has an acoustic velocity higher than the acoustic velocity of the center area, where the length direction is a direction in which the first to third electrode fingers extend.

Abstract: A void-arranged structure that includes a pair of principal surfaces opposing each other and a plurality of void sections that penetrate through the pair of principal surfaces. The void-arranged structure is configured of a plurality of unit structures each of which includes a first void section and a second void section having a different shape from a shape of the first void section, and the overall shape of the unit structure, when the principal surface is viewed from above, is not mirror-symmetric with respect to a predetermined imaginary plane orthogonal to the principal surface of the void-arranged structure.

Abstract: A void-arranged structure that includes a pair of principal surfaces opposing each other and a plurality of void sections that penetrate through the pair of principal surfaces. The void-arranged structure is configured of a plurality of unit structures each of which includes a first void section and a second void section having a different shape from a shape of the first void section, and the overall shape of the unit structure, when the principal surface is viewed from above, is not mirror-symmetric with respect to a predetermined imaginary plane orthogonal to the principal surface of the void-arranged structure.

Abstract: A measuring method for measuring characteristics of an object to be measured, the measuring method including holding the object on a void-arranged structure having at least two void portions that pass therethrough in a direction perpendicular to a principal surface thereof, and applying electromagnetic waves to the void-arranged structure on which the object is held to detect frequency characteristics of the electromagnetic waves transmitted through the void-arranged structure. The void-arranged structure has a grid structure in which the void portions are periodically arranged in at least one direction on the principal surface of the void-arranged structure. The characteristics of the object are measured on the basis of a relationship between a first frequency characteristic and a second frequency characteristic.

Abstract: A measurement method that includes irradiating a void-arranged structure on which an analyte has been held with an electromagnetic wave, detecting an electromagnetic wave scattered on the void-arranged structure, and determining a property of the analyte on the basis of at least one parameter, the parameter including the amount of change in the ratio of the detected electromagnetic wave to the irradiated electromagnetic wave at a specific frequency between the presence and the absence of the analyte.

Abstract: A plate-shaped periodic structure is provided that includes at least two aperture portions extending through the periodic structure in a direction perpendicular to a main surface of the periodic structure and periodically arranged in at least one direction along the main surface. Each of the aperture portions has a shape that is not mirror-symmetric with respect to an imaginary plane that is a plane perpendicular to the main surface. Each of the aperture portions includes a constricted portion at which a gap distance of the aperture portion is partially small, the gap distance being a width in a direction parallel to a line of intersection of the main surface and the imaginary plane.

Abstract: The present invention provides a measuring method comprising the steps of holding a specimen on a flat-plate periodic structure, applying a linearly-polarized electromagnetic wave to the periodic structure, and measuring characteristics of the specimen based on change of the electromagnetic wave scattered forward or backward by the periodic structure, wherein the periodic structure is structured such that plural unit structures having the same shape are two-dimensionally and periodically interconnected in a direction of one reference plane, the unit structure has at least one aperture penetrating therethrough in a direction perpendicular to the reference plane, the electromagnetic wave is applied from a direction perpendicular to the reference plane, and the unit structure has a shape that is not mirror-symmetric with respect to an imaginary plane orthogonal to a polarizing direction of the electromagnetic wave.

Abstract: A method of measuring characteristics of a specimen, the measuring method including the steps of bonding the specimen to a host molecule on a sensing device, emitting an electromagnetic wave of a particular frequency to the sensing device to which the specimen is bonded, measuring a frequency characteristic of the transmitted or reflected light, and measuring the characteristics of the specimen based on a change of the frequency characteristic, wherein an absorbance of the host molecule per unit quantity at the particular frequency is smaller than that of the specimen.