High-sensitivity fast on-line detection method of optical thin film and element surface laser-induced damage

Abstract

The invention discloses a high-sensitivity fast on-line detection method of optical thin film and element surface laser-induced damage and relates to the field of optical thin film and element surface laser-induced damage and life detection. The method utilizes a He-Ne light scattering detection method as a main detection method and utilizes a microscopic CCD imaging detection method as an auxiliary detection method. Aiming at each one test sample point, the high-sensitivity fast on-line detection method comprises carrying out detection by the He-Ne light scattering detection method as an optical thin film and element surface laser-induced damage determination basis, if the He-Ne light scattering detection result shows the optical thin film and element surfaces produce laser-induced damage, suspending the He-Ne light scattering detection, recording radiation laser pulse number, determining the He-Ne light scattering detection result by the microscopic CCD imaging detection method, and testing the next test point by the same methods so that detection of laser-induced damage on the whole surface is finished. The high-sensitivity fast on-line detection method realizes effective combination of the He-Ne light scattering detection method and the microscopic CCD imaging detection method and greatly improves sensitivity and reliability of optical thin film and element surface laser-induced damage on-line detection.

Description

technical field [0001] The invention relates to applications in the field of laser damage and life testing of optical thin films and components, in particular to a highly sensitive and rapid on-line detection method for laser damage on the surface of optical thin films and components. Background technique [0002] The laser damage of optical thin films and components has always been one of the main factors that limit the development of lasers to higher energy and power, and affect the service life of the entire laser application system. It is of great practical significance to study how to improve the laser damage threshold of optical thin films and components. [0003] One of the prerequisites for the laser damage threshold test of optical films and components is to detect and judge the surface damage of optical films and components. Accuracy has a significant impact. At present, the methods actually used for laser damage determination of optical thin films and components...

AI Technical Summary

Problems solved by technology

This method has high accuracy, the result is relatively intuitive, and it is easy to compare and judge, but there are also some shortcomings in actual use: first, when the radiation point damage of the sample is not obvious, its damage morphology is difficult to be accurately detected in an off-line microscope. Positioning, which will lead to mistakes in judging whether it is damaged; secondly, in the differential interference microscope observation, due to the relatively weak illumination intensity and the focus of the observation surface, when the magnification exceeds 200 times, the clarity of the microscopic imaging It will degenerate, making it difficult to observe and accurately judge the surface topography, and it is difficult to observe and judge smaller or weak damage topography, thus restricting the sensitivity of this method

However, in actual use, due to the constraints of the response rate and image processing rate of the CCD camera, the detection rate achievable by this method is limited, and it can only be used for a relatively low test repetition frequency.

In addition, at present, this method generally uses damage irradiation laser as the illumination source for microscopic imaging, which is seriously affected by the uniformity and stability of the imaging illumination source in the actual use process.

[0007] To sum up, although the current international standard ISO 21254 has clearly stipulated the identification methods of optical film and component laser damage and component surface damage in life testing, in actual work, only the above three methods are often used. However, it is known from the above analysis that the above three methods currently have obvious deficiencies, which make the detection sensitivity of the existing methods unsatisfactory, especially in the online rapid detection of component damage. With the further improvement of the discrimination sensitivity requirements for laser surface damage of components, it is urgent to develop an online rapid detection method for optical thin film and component laser damage with higher sensitivity and reliability.

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