5 results about "Brewster's angle" patented technology

An aircraft radome and radar assembly includes: a radome arranged on the nose of the aircraft; a radar inside the radome, the radar operating in the millimeter domain and including a transmission antenna for emitting a TM polarized wave and a reception antenna; the radome includes an integrated window in front of the radar, the window being of a material transparent to millimeter waves; the radar being arranged so the angle between the maximum gain direction of the transmission antenna and the normal to the window is within an angular range [θB−θ1; θB+θ2], with OB being the Brewster angle for an air / window interface, θ1 and θ2 determined to obtain reflectivity at said air / window interface less than a predefined threshold; and an isolation partition between the transmission antenna and the reception antenna, the isolation partition being substantially in contact with the window and with the radar.

The application discloses a Brewster window stack polarization modulation device. The device comprises a Brewster window stack assembly, a clamping assembly, and an installation base. The Brewster window stack assembly comprises a plurality of optical window pieces arranged in parallel and at intervals, and the included angle between the surface normal and the incident light is a Brewster angle. The installation base has a vertical part and a horizontal part. The clamping baffle is arranged opposite to the vertical part of the installation base at intervals. The optical window pieces and the gaskets are alternately arranged in parallel at intervals. One adjusting screw is arranged on each side of the installation base. The adjusting screw passes through the clamping baffle and each gasket in sequence, and is screwed with the vertical part of the installation base. The rotation of the adjusting screw is converted into the linear motion of the clamping baffle along the support surface, so as to change the distance between the clamping baffle and the vertical part and / or realize the clamping and fixing of the Brewster window stack assembly. The device can realize linearly polarized light output with high extinction ratio and high stability in a wide range of incident angles and spectral bands.

The present invention relates to a preparation method for a trigonal nonlinear optical crystal frequency converter and an operating method. The frequency converter has a first group of parallel surfaces and a second group of parallel surfaces, wherein the first group of parallel surfaces is parallel to a c-axis and an a-axis of an optical crystal, an angle α is formed between a normal of the second group of parallel surfaces and the c-axis, and an included angle β is formed between the projection of the normal on an a-b plane and the a-axis; and θPM having a relation shown in Formula (1) and Formula (2) is a phase matching angle of the nonlinear optical crystal satisfying an incident fundamental frequency light and an emergent variable frequency light, where θB=arctann, which is a Brewster angle, n is the refractive index of the nonlinear optical crystal corresponding to the incident fundamental frequency light, and the second group of parallel surfaces includes a light transmission input surface and a light transmission output surface of the frequency converter. The present invention provides, on the basis of a thin sheet-like primary crystal, a preparation method for a nonlinear optical crystal frequency converter having a length in a light transmission direction as large as possible and suitable for continuous wave application and an operating method.

The application relates to the technical field of tube cover closure detection, and discloses a visual recognition-based ultrafiltration centrifuge tube cover closure integrity detection method, which comprises the following steps: collecting basic polarization data, performing polarization heterogeneity preliminary screening, collecting geometric and full Stokes data, performing curved surface geometric artifact correction, collecting topography and multi-scale texture data, performing elastic deformation compensation, and performing multi-scale texture arbitration. The visual recognition-based ultrafiltration centrifuge tube cover closure integrity detection method realizes rapid non-contact detection and efficient preliminary screening of the tube cover closure state, eliminates the interference of Brewster angle artifacts caused by complex curved surfaces, significantly reduces the geometric misjudgment rate, compensates for the micro-deformation interference caused by clamping and temperature, enhances the adaptability of the system to changes in the production line working conditions, accurately identifies the mold parting line and the real closed gap, fundamentally solves the problems of overkill and missed detection, and comprehensively improves the reliability and accuracy of the ultrafiltration centrifuge tube cover closure integrity detection.

The present application relates to the technical field of tidal creek geomorphology monitoring, and particularly relates to a tidal creek geomorphology monitoring method based on airborne adaptive polarization hyperspectrum, which comprises the following steps: obtaining initial hyperspectrum data flow and establishing a water body index matrix; monitoring the spatial difference gradient of the matrix, and calibrating the detection field of view to enter the shallow water and wet silt mixed zone when detecting that the adjacent pixels produce numerical jump; calculating two limit phase points constituted by the pure water surface and the pure wet silt theoretical extinction angle according to the calculated double Brewster angle difference, driving the polaroid to complete micro-step reciprocating switching within the single imaging integration time; guiding the incident light beam to alternately strip the contained water surface and silt surface glare through the switching action, and generating photoelectric signals by using high and low gain double channels; and using adaptive threshold to carry out pixel-level reconstruction, and outputting a wide dynamic hyperspectrum data cube which eliminates data saturation and shows the spectral characteristics of the water body bottom sediments and microalgae.