Wavefront error correction system and method for inhibiting speckle noises of coronagraph system

Abstract

The invention discloses a wavefront error correction system and method for inhibiting speckle noises of a coronagraph system. A processor is used for outputting a control voltage signal to an actuator in a first deformable mirror according to light strength information received from an amplitude detector and driving the first deformable mirror to correct a wavefront amplitude error; the processor is used for outputting a control voltage signal to an actuator in a second deformable mirror according to light strength information received from an image surface detector and driving the second deformable mirror to correct a wavefront phase error so as to inhibit the speckle noises of the coronagraph system in a dark hole region of the image surface detector. The invention discloses a wavefront error correction method for inhibiting the speckle noises of the coronagraph system. The method comprises the following steps: firstly, selecting a suitable evaluation function according to the selected coronagraph system; adopting a random gradient descent algorithm to apply disturbance voltage signals to the actuators of the deformable mirrors by a plurality of times of iteration; and finally, enabling the evaluation function to be the minimum so as to correct the wavefront errors and greatly improve the imaging contrast ratio of a coronagraph.

Description

technical field [0001] The invention relates to the field of optical technology, in particular to a correction system and method for speckle noise of a coronagraph system. Background technique [0002] In order to avoid the influence of atmospheric turbulence on imaging contrast, the direct imaging detection of terrestrial planets will be realized with the help of space telescopes in the future. The speckle noise caused by the quasi-static mirror surface shape error of the space telescope will be the main factor restricting the imaging contrast. The calculation results based on the surface shape error of the Hubble Space Telescope's primary mirror show that the speckle noise caused by the surface shape error will be 104 times brighter than the planet (assuming that the contrast between the planet and the star is 10-9), and effective measures must be taken to reduce the speckle noise to eliminate or suppress. Adaptive optics technology is one of the key technologies for sup...

AI Technical Summary

Problems solved by technology

However, the speckle nulling method has the following disadvantages: 1) The speckle nulling method uses linear approximation in the detection and correction of wavefront errors, and the algorithm is only in the range of small aberrations (that is, satisfying efficient

[0005] The early speckle elimination method only uses a deformable mirror to correct the amplitude and phase of the light wave, and can only produce an asymmetric high-contrast imaging area in one and a half areas of the image plane.

Images