Abstract: An optical microphone includes: an acousto-optic medium section having a pair of principal surfaces and at least one lateral surface provided therebetween; a restraint section which is in contact with the at least one lateral surface for preventing a shape change of the acousto-optic medium section; and a light emitting section for emitting a light wave so as to propagate through the acousto-optic medium section between the pair of principal surfaces. The pair of principal surfaces are in contact with an environmental fluid through which an acoustic wave to be detected is propagating and are capable of freely vibrating, and an optical path length variation of a light wave propagating through the acousto-optic medium section, which is caused by the acoustic wave that comes into the acousto-optic medium section from at least one of the pair of principal surfaces and propagates through the acousto-optic medium section, is detected.

Abstract: An optical microphone for detecting an acoustic wave propagating through an environmental fluid by using a light wave, includes: an acoustic wave receiving section having a propagation medium portion through which an acoustic wave propagate and a first support portion for supporting the propagation medium portion; a light source for outputting a light wave so that the light wave passes through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a light-blocking portion having an edge line for splitting the light wave having passed through the propagation medium portion into a blocked portion and a non-blocked portion; and a photoelectric conversion section for receiving a portion of the light wave having passed through the propagation medium portion which has not been blocked by the light-blocking portion to output an electric signal.

Abstract: A porous silica material disclosed in the present application is a porous silica material in which a plurality of silica particles are connected to one another three-dimensionally, wherein: a density of the porous silica material is less than 220 kg/m3; a particle diameter of the silica particles is 3.5 nm or more; and the water content of the porous silica material is 8 wt % or less.

Abstract: A porous silica material in which silica particles are connected to one another three-dimensionally, wherein: the porous silica material includes a through hole including first pores smaller than a mean free path of an air, and second pores larger than the first pores; the porous silica material has a density of 100 kg/m3 or more and 300 kg/m3 or less; and an isobutyl group is bound to silicon of silica of the silica particles.

Abstract: An optical microphone includes: a light source; a first polarizer for allowing linearly-polarized light, of light output from the light source, to pass therethrough; a second polarizer for allowing linearly-polarized light having a different polarization plane from the first polarizer to pass therethrough; a sound-receiving section including an acoustic medium having a smaller sound velocity than the air, wherein an acoustic signal propagates through the acoustic medium, the sound-receiving section being arranged so that the linearly-polarized light from the first polarizer passes through the acoustic medium and enters the second polarizer; and a photodetector for converting an intensity of light having passed through the second polarizer to an electric signal, wherein between the first polarizer and the second polarizer, the linearly-polarized light having passed through the first polarizer is given different phase shifts in two orthogonal directions which are each different from a polarization direction.

Abstract: An optical microphone includes: a propagation medium portion; a light source to output a light wave passing through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a reflecting section to retroreflect the light wave having passed through the propagation medium portion; and a photoelectric conversion section to receive the light wave having been reflected by the reflecting section and passed through the propagation medium portion to output an electric signal. 0th-order, +1st-order and ?1st-order diffracted light waves are respectively produced on outward and return paths, by virtue of a refractive index distribution across the propagation medium portion caused by the propagation of the acoustic wave therethrough. The photoelectric conversion section detects interference light between the +1st-order or ?1st-order diffracted light wave of the outward path and the ?1st-order or +1st-order diffracted light wave of the return path.

Abstract: An acousto-optic image capture device includes: an acoustic wave source to irradiating an object with an acoustic wave; an acoustic lens system which transforms a scattered wave from the object into a plane acoustic wave; an acousto-optic medium portion which is arranged so that the scattered wave transmitted through the acoustic lens system is incident there; a light source to emit a light beam in which monochromatic rays of light with different traveling directions are superposed and which is incident on the acousto-optic medium portion; an imaging lens system which condenses diffracted rays of light of the plane wave monochromatic rays of light produced by the acousto-optic medium portion; and an image receiving member which detects the rays of light condensed by the imaging lens system to output an electrical signal. The acoustic lens system includes at least two reflecting mirrors.

Abstract: There is provided an optical microphone for detecting an acoustic wave propagating in an ambient fluid, the optical microphone including: a propagation medium section; a light source for emitting a light wave to be transmitted through a diffraction region in the propagation medium section; and a photoelectric conversion section for detecting the light wave having been transmitted through the propagation medium section. A first acoustic wave which is a portion of the acoustic wave and a second acoustic wave which is another portion thereof are allowed to propagate in the propagation medium section so as to simultaneously arrive at the diffraction region, and an interference component between a +1st order diffracted light wave and a ?1st order diffracted light wave of the light wave generated based on a refractive index distribution of the propagation medium occurring in the diffraction region.

Abstract: An acousto-optic image capture device includes: an acoustic beam source, an acoustic lens system; an acousto-optic medium portion arranged on the path of the scattered wave transmitted through the acoustic lens system; a light source that emits a light beam including monochromatic rays of light toward the acousto-optic medium portion obliquely; an imaging lens system that condenses diffracted rays of light produced by the acousto-optic medium; and an image receiving section that detects the rays of light condensed by the imaging lens system. The acoustic lens system includes at least a telecentric acoustic system and a sound-collecting acoustic system arranged on the image space. The distance between acoustic systems is equal to the sum of the respective focal lengths of the telecentric acoustic system and the sound-collecting acoustic system. The light beam is transmitted at the focal point of the sound-collecting acoustic system through the acousto-optic medium portion.

Abstract: An acousto-optic imaging device includes: an ultrasonic wave transmitter for transmitting a divergent ultrasonic wave into a subject; an acoustic lens for converging a reflection ultrasonic wave derived from the ultrasonic wave from the subject; an acousto-optic cell including an acousto-optic propagation medium section which has a smaller sound velocity than the subject and through which the reflection ultrasonic wave converged by the acoustic lens propagates; a light source for emitting convergent light so as to irradiate the reflection ultrasonic wave propagating through the acousto-optic propagation medium section in a direction not parallel to a traveling direction of the reflection ultrasonic wave; and an image formation optical system for detecting Bragg diffracted light of the convergent light which is produced in the acousto-optic propagation medium section and converting the detected Bragg diffracted light to an electric signal.

Abstract: An acousto-optic vibrometer includes: an acoustic wave source to irradiating an object with an acoustic wave; an acoustic lens system which places a scattered wave from the object into a predetermined converged state; an acousto-optic medium portion in which the scattered wave transmits; a sensing light source to emit a sensing light beam in which monochromatic rays of light with different traveling directions are superposed and which is incident on the acousto-optic medium portion; a reference light source to emit a reference light beam in which monochromatic rays of light with different traveling directions are superposed and which is to be superposed on sensing light beam based diffracted light produced by the acousto-optic medium portion; an imaging lens system which converges the diffracted light on which the reference light beam is superposed; and an image receiving section which senses the light converged by the imaging lens system.

Abstract: A moisture content fluctuation detection device including: a silica aerogel placed, disposed to a measurement object space; and a detection unit configured to detect fluctuation in moisture content within the measurement object space, the detection unit including: a light source configured to emit light to the silica aerogel, the light having at least a portion of a range of wavelengths of 1850 nm or greater and 1970 nm or less; a light receiving unit configured to receive the light which has passed through the silica aerogel and has at least a portion of the range of wavelengths of 1850 nm or greater and 1970 nm or less; and a calculation unit configured to calculate the fluctuation in moisture content within the measurement object space from change in light intensity of the light received by the light receiving unit.

Abstract: A porous silica material disclosed in the present application is a porous silica material in which a plurality of silica particles are connected to one another three-dimensionally, wherein: a density of the porous silica material is less than 220 kg/m3; a particle diameter of the silica particles is 3.5 nm or more; and the water content of the porous silica material is 8 wt % or less.

Abstract: An optical microphone for detecting an acoustic wave propagating through an environmental fluid by using a light wave, includes: an acoustic wave receiving section having a propagation medium portion through which an acoustic wave propagate and a first support portion for supporting the propagation medium portion; a light source for outputting a light wave so that the light wave passes through the propagation medium portion across the acoustic wave propagating through the propagation medium portion; a light-blocking portion having an edge line for splitting the light wave having passed through the propagation medium portion into a blocked portion and a non-blocked portion; and a photoelectric conversion section for receiving a portion of the light wave having passed through the propagation medium portion which has not been blocked by the light-blocking portion to output an electric signal.

Abstract: A method of producing a porous silica material includes: preparing a raw material solution containing silicon alkoxides including diisobutyldimethoxysilane and tetramethoxysilane in such a mass ratio that a mass of the diisobutyldimethoxysilane is 0.25 or more and 1 or less per mass of the tetramethoxysilane, and a solvent; obtaining a wet gel by adding, to the raw material solution, an aqueous solution containing a catalyst for promoting hydrolysis and condensation polymerization of the silicon alkoxides, the aqueous solution having a pH of 8.9 or more and 11.3 or less; washing the wet gel; and drying the washed wet gel under supercritical conditions.

Abstract: An acousto-optic imaging system includes: an ultrasonic wave source for irradiating an imaged object with an ultrasonic wave; an acoustic lens for converting a scattered wave of the ultrasonic wave to a plane wave; a light-transmitting acoustic medium provided in an area on an opposite side of the imaged object with respect to the acoustic lens; a light source for outputting a monochromatic light plane wave; an image-forming lens arranged so as to condense diffraction light of the monochromatic light plane wave which is produced in the light-transmitting acoustic medium; an image-receiving section for obtaining an optical image formed by the image-forming lens; and a distortion compensation section for correcting a distortion of the optical image or a distortion.

Abstract: A method of producing a porous silica material includes: preparing a raw material solution containing silicon alkoxides including diisobutyldimethoxysilane and tetramethoxysilane in such a mass ratio that a mass of the diisobutyldimethoxysilane is 0.25 or more and 1 or less per mass of the tetramethoxysilane, and a solvent; obtaining a wet gel by adding, to the raw material solution, an aqueous solution containing a catalyst for promoting hydrolysis and condensation polymerization of the silicon alkoxides, the aqueous solution having a pH of 8.9 or more and 11.3 or less; washing the wet gel; and drying the washed wet gel under supercritical conditions.

Abstract: An optical microphone includes: an acousto-optic medium section having a pair of principal surfaces and at least one lateral surface provided therebetween; a restraint section which is in contact with the at least one lateral surface for preventing a shape change of the acousto-optic medium section; and a light emitting section for emitting a light wave so as to propagate through the acousto-optic medium section between the pair of principal surfaces. The pair of principal surfaces are in contact with an environmental fluid through which an acoustic wave to be detected is propagating and are capable of freely vibrating, and an optical path length variation of a light wave propagating through the acousto-optic medium section, which is caused by the acoustic wave that comes into the acousto-optic medium section from at least one of the pair of principal surfaces and propagates through the acousto-optic medium section, is detected.

Abstract: An acousto-optic imaging device disclosed in the present application includes: an acoustic wave source; an acoustic lens system for converting a scattered wave produced by irradiation of an object with an acoustic wave emitted from the acoustic wave source into a predetermined converged state; an acousto-optic medium section which is arranged such that a scattered wave transmitted through the acoustic lens system is incident on the acousto-optic medium section; a light source for emitting a light beam which is formed by a plurality of superposed monochromatic light rays traveling in different directions; an image formation lens system for condensing diffracted light of a plurality of the monochromatic plane wave light rays produced at the acousto-optic medium section; and an image receiving section for detecting light condensed by the image formation lens system to output an electric signal.

Abstract: An optical microphone includes: a light source; a first polarizer for allowing linearly-polarized light, of light output from the light source, to pass therethrough; a second polarizer for allowing linearly-polarized light having a different polarization plane from the first polarizer to pass therethrough; a sound-receiving section including an acoustic medium having a smaller sound velocity than the air, wherein an acoustic signal propagates through the acoustic medium, the sound-receiving section being arranged so that the linearly-polarized light from the first polarizer passes through the acoustic medium and enters the second polarizer; and a photodetector for converting an intensity of light having passed through the second polarizer to an electric signal, wherein between the first polarizer and the second polarizer, the linearly-polarized light having passed through the first polarizer is given different phase shifts in two orthogonal directions which are each different from a polarization direction.