Abstract: A wind velocity searching unit 30 is configured so as to, when a spectrum signal calculated by a spectrum calculating unit 22 is one in a range bin having a signal strength less than a first threshold Th1, determine a search center IF of the search scope for a Doppler frequency corresponding to a wind velocity in the range bin by using a wind velocity model selected by a wind velocity model selecting unit 29, and search for the wind velocity in the range bin from the spectrum signal within the search scope whose search center IF is determined thereby. As a result, the probability that the peak of noise is detected erroneously as the peak of the spectrum signal is reduced.

Abstract: A wind velocity searching unit 30 is configured so as to, when a spectrum signal calculated by a spectrum calculating unit 22 is one in a range bin having a signal strength less than a first threshold Th1, determine a search center IF of the search scope for a Doppler frequency corresponding to a wind velocity in the range bin by using a wind velocity model selected by a wind velocity model selecting unit 29, and search for the wind velocity in the range bin from the spectrum signal within the search scope whose search center IF is determined thereby. As a result, the probability that the peak of noise is detected erroneously as the peak of the spectrum signal is reduced.

Abstract: A laser radar device includes a multi-wavelength light oscillator to generate a plurality of light beams with different wavelengths, a plurality of modulation units to modulate each of the plurality of light beams with a modulation frequency altered according to a corresponding line of sight of emission, a transmitting/receiving optical system to emit each of the light beams modulated by the modulation units in a corresponding line of sight, and receive reflected light beams, an optical receiver to perform heterodyne detection by using the generated light beams and the received light beams corresponding to the generated light beams, and detect beat signals in the respective lines of sight, and a signal analyzing unit to calculate a value of Doppler wind speed in the respective lines of sight from the respective beat signals, and calculate a value of three-dimensional wind speed using the values of Doppler wind speed.

Abstract: A laser illumination device for providing a light intensity distribution of a high-intensity and uniform illumination light flux is obtained. The device includes a plurality of light source modules (20) each including: a plurality of light source units (8), in each of which a semiconductor laser (1), and a laser medium (5) and a nonlinear material (7) which are flat-shaped and have a waveguide structure are arranged on the same plane, for performing continuous oscillation in a waveguide mode of the laser medium (5); and a first optical system (12) for coupling laser oscillation beams from the plurality of light source units (8).

Abstract: A laser illumination device for providing a light intensity distribution of a high-intensity and uniform illumination light flux is obtained. The device includes a plurality of light source modules (20) each including: a plurality of light source units (8), in each of which a semiconductor laser (1), and a laser medium (5) and a nonlinear material (7) which are flat-shaped and have a waveguide structure are arranged on the same plane, for performing continuous oscillation in a waveguide mode of the laser medium (5); and a first optical system (12) for coupling laser oscillation beams from the plurality of light source units (8).

Abstract: Provided is a compact and bright imaging optical system having a high resolution. The imaging optical system includes three reflectors composed of a first reflector (1), a second reflector (2), and a third reflector (3) that are arranged in this order on an optical path of incident ray so as not to block the incident light. In the imaging optical system, in which light beams reflected by the three reflectors form an image plane (4), a convex mirror is used for any one of the first reflector (1) and the third reflector (3) and a concave mirror is used for the other thereof, and vertexes of a triangular dipyramid (6) are defined in terms of a central chief ray (5) by an appropriate point on the central chief ray (5) that is incident to the first reflection surface, a reflection point of each central chief ray on the first to third reflection surfaces, and an image forming point of the central chief ray.

Abstract: Provided is a compact and bright imaging optical system having a high resolution. The imaging optical system includes three reflectors composed of a first reflector (1), a second reflector (2), and a third reflector (3) that are arranged in this order on an optical path of incident ray so as not to block the incident light. In the imaging optical system, in which light beams reflected by the three reflectors form an image plane (4), a convex mirror is used for any one of the first reflector (1) and the third reflector (3) and a concave mirror is used for the other thereof, and vertexes of a triangular dipyramid (6) are defined in terms of a central chief ray (5) by an appropriate point on the central chief ray (5) that is incident to the first reflection surface, a reflection point of each central chief ray on the first to third reflection surfaces, and an image forming point of the central chief ray.

Abstract: An optical antenna includes an optical element mount (3) for mounting fiber ends (1a and 2a) of optical fibers (1 and 2) at different positions; and an optical transmitting and receiving system (4) for collimating, when laser beams are radiated from the fiber ends (1a and 2a), the laser beams to parallel light rays toward the space, and for focusing, when laser beams arrive from the space, the laser beams onto the fiber ends (1a and 2a) This makes it possible to set two optical transmitting and receiving directions 5 and 6 without installing complicated mechanical elements.

Abstract: An optical antenna includes an optical element mount (3) for mounting fiber ends (1a and 2a) of optical fibers (1 and 2) at different positions; and an optical transmitting and receiving system (4) for collimating, when laser beams are radiated from the fiber ends (1a and 2a), the laser beams to parallel light rays toward the space, and for focusing, when laser beams arrive from the space, the laser beams onto the fiber ends (1a and 2a) This makes it possible to set two optical transmitting and receiving directions 5 and 6 without installing complicated mechanical elements.

Abstract: Disclosed is an image capturing apparatus comprising a primary mirror 1 that has a surface which is a section of a surface cut out from a paraboloid with a single focus; a secondary mirror 2 that has a surface which is a section of a surface cut out from a hyperboloid with two foci; and a photodetector 3 which converts the light signal coming from the secondary mirror 2 into an electric signal. The secondary mirror 2 is placed in a position where one of its foci and the focus of the primary mirror 1 match with each other. The photodetector 3 is placed near the other focus of the secondary mirror 2. By using two mirrors, the light from the object is led to the photodetector 3 without being shaded.

Abstract: A bright wide-angle catoptric system is provided which will not deteriorate the picture quality of images. The wide-angle catoptric system includes, successively from an object, a secondary reflecting mirror having a concave surface, a primary reflecting mirror having a convex surface and a tertiary reflecting mirror having a concave surface, and produces images by reflecting the luminous flux from the object at the primary reflecting mirror, the secondary reflecting mirror and the tertiary reflecting mirror successively. The system also includes a diaphragm arranged in close proximity to the primary reflecting mirror so as to have an optical axis pass through the center of the diaphragm; the optical axis is a straight line connecting the curvature center of the primary reflecting mirror to the curvature center of the secondary reflecting mirror. The tertiary reflecting mirror has its curvature center decentered from the optical axis in the direction of lesser astigmatism.

Abstract: A field flattener having a function of flattening a bent image surface on which an image is formed through an optical system, is composed of a material of which a refractive index is equal to or larger than 2. A sectional configuration of the field flattener cut in an optical-axis direction containing the optical axis is formed to take a stepped shape toward its peripheral edge from the optical axis. An axial height of the stepped portion configuring the surface in the optical-axis direction in this stepped shape is set so as to equal to or larger than twice a wavelength of beams to be used.

Abstract: An infrared transparent optical element for use as an optical window for an infrared imaging camera includes an infrared transparent substrate, an antireflection film, and a protective film of a polymer material. The infrared transparent substrate has first and second major surfaces opposite each other, and the antireflection film is disposed on each of the first and second major surfaces of the substrate. The protective film is on an outer surface of the antireflection film on the first major surface of the substrate.

Abstract: A field flattener having a function of flattening a bent image surface on which an image is formed through an optical system, is composed of a material of which a refractive index is equal to or larger than 2. A sectional configuration of the field flattener cut in an optical-axis direction containing the optical axis is formed to take a stepped shape toward its peripheral edge from the optical axis. An axial height of the stepped portion configuring the surface in the optical-axis direction in this stepped shape is set so as to equal to or larger than twice a wavelength of beams to be used.

Abstract: An infrared optical system for infrared cameras has a convex lens held by a holding member composed of a low-dispersion material that transmits infrared light. A stop for restricting light beams entering the convex lens is disposed on an object side from the convex lens. An aberration correcting plate for reducing spherical aberration is provided in the vicinity of the stop. A field flattener, the thickness of which changes along image height to offset curvature of field, is disposed on an image side of the convex lens.

Abstract: An infrared transparent optical element of the invention is for use as an optical window for an infrared imaging camera. The optical element includes an infrared transparent substrate, an antireflection film, and a protective film made of a polymer material. The infrared transparent substrate has first and second major surfaces opposite to each other, and the antireflection film is formed on each of the first and second major surfaces of the substrate. The protective film is formed on an outer surface of the antireflection film on the first major surface of the substrate.