Angular aperture

About: Angular aperture is a research topic. Over the lifetime, 1771 publications have been published within this topic receiving 27257 citations.

Micro Ring Grating Spectrometer with Adjustable Aperture

Abstract: A spectrometer includes a micro-ring grating device having coaxially-aligned ring gratings for diffracting incident light onto a target focal point, a detection device for detecting light intensity, one or more actuators, and an adjustable aperture device defining a circular aperture. The aperture circumscribes a target focal point, and directs a light to the detection device. The aperture device is selectively adjustable using the actuators to select a portion of a frequency band for transmission to the detection device. A method of detecting intensity of a selected band of incident light includes directing incident light onto coaxially-aligned ring gratings of a micro-ring grating device, and diffracting the selected band onto a target focal point using the ring gratings. The method includes using an actuator to adjust an aperture device and pass a selected portion of the frequency band to a detection device for measuring the intensity of the selected portion.

Zoom optical system, image sensing device, and digital apparatus

Abstract: A zoom optical system includes first through fourth lens groups having negative-positive-negative-positive optical powers. Assuming that a curvature radius of an object-side lens surface of a negative lens element in the first lens group is r1, a curvature radius of an image-side lens surface of the negative lens element in the first lens group is r2, a focal length of the third lens group is f3, a focal length of the entirety of the optical system at the wide angle end is fw, a focal length of the entirety of the optical system at the telephoto end is ft, and an average refractive index of positive lens elements in the second lens group is nd2p, the zoom optical system satisfies the conditional expressions: 0<( r 1+ r 2)/( r 1− r 2)<1.0 −0.9< f 3/√{square root over ( )}( fw×ft )<−0.4 1.6

Scalar beam diffraction by a wide circular aperture

Abstract: The complex-source-point technique and the geometrical theory of diffraction constitute a powerful combination for the rigorous solution of high-frequency diffraction problems. Here scalar diffraction by a beam normally incident upon a circular aperture is analyzed, a situation involving shadow boundaries, multiple diffraction, and an axial caustic. The result is a simple and accurate uniform solution that satisfies the boundary conditions in the aperture plane. Numerical results are shown for a circular aperture of radius 1.5λ and incident beams of varying directivity.

Gauss type large aperture photographic objective

Abstract: In the device disclosed, eight elements form a Gauss type wide or large aperture objective. The first element counting from the front is a positive meniscus lens of forward convexity, the second is a positive lens of convex curvature toward the front, the third is cemented to the second and is a negative lens of concave curvature toward the rear, the fourth is a negative lens of concave curvature toward the front, the fifth is cemented to the fourth and is a positive lens of convex curvature toward the rear, the sixth is a positive meniscus lens of rearward convexity, the seventh is a bi-convex lens with the rear surface of stronger curvature, and the eighth is a positive lens. The front surface of the second lens is aspherical so that as the distance from the optical axis increases, the deviation of the surface from the spherical surface of paraxial radius increases in a direction toward the front.