Method for non-distructive measurement or comparison of a laser radiation content in optical components
First Claim
1. ) A predictive choice process of a manufacturing process of an optical component intended to be subjected to laser fluxes, the choice being intended to select from among several possible manufacturing processes that which results in components having better laser flux behaviour than those obtained by the other possible processes, characterised in that a) a number N of measurements of cathodoluminescence are made on components obtained by a first of the possible manufacturing processes, while the component receives an electronic beam having a determined energy, a determined focusing at the surface of the component and a determined intensity controlled by a value of a ground current measured on the component, while it is being submitted to said electronic beam, b) an average cathodoluminescence value on the N measurements is calculated, c) operations a) and b) on components obtained by each of the other possible manufacturing processes are repeated, d) the most advantageous manufacturing process is decided as the one for which the average cathodoluminescence value is the lowest.
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Abstract
A predictive choice process of a manufacturing process of an optical component intended to be subjected to laser fluxes, the choice being intended to select from among several possible manufacturing processes that which results in components having better laser flux behaviour than those obtained by the other possible processes characterised in that a) a number N of cathodoluminescence measurements are made on components obtained by a first of the possible manufacturing processes, while the component receives an electronic beam having a determined energy, a focus on the surface of the determined component and a determined intensity controlled by a value of a ground current measured on the component, while it is being subjected to said electronic beam, b) an average cathodoluminescence value on the N measurements is calculated, c) operations a) and b) on components obtained by each of the other possible manufacturing processes are repeated, d) the most advantageous manufacturing process is decided as the one for which the average cathodoluminescence value is the lowest.
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Citations
6 Claims
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1. ) A predictive choice process of a manufacturing process of an optical component intended to be subjected to laser fluxes, the choice being intended to select from among several possible manufacturing processes that which results in components having better laser flux behaviour than those obtained by the other possible processes, characterised in that
a) a number N of measurements of cathodoluminescence are made on components obtained by a first of the possible manufacturing processes, while the component receives an electronic beam having a determined energy, a determined focusing at the surface of the component and a determined intensity controlled by a value of a ground current measured on the component, while it is being submitted to said electronic beam, b) an average cathodoluminescence value on the N measurements is calculated, c) operations a) and b) on components obtained by each of the other possible manufacturing processes are repeated, d) the most advantageous manufacturing process is decided as the one for which the average cathodoluminescence value is the lowest.
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3. ) A process for controlling a state of a surface of an optical component intended to be a surface of incidence of a laser beam, so as to determine whether said surface has a default density which is less than a default density beyond which the optical component is likely to be damaged by submission to a laser flux having a power (flux density) at most equal to a predetermined threshold for a maximum predetermined duration, characterised in that
a) samples of said optical component are produced by the same manufacturing process, in particular as concerns the state of said incident surface, and they are separated into first and second samples, b) in a preliminary calibration phase a correlation between cathodoluminescence values obtained in conditions of determined electronic shots, and laser flux behaviour of the first samples is made on the first samples, this correlation helping to determine one or more cathodoluminescence thresholds, each threshold corresponding to behaviour conditions of the first samples to laser flux, a component having a cathodoluminescence value less than one of the thresholds being acceptable for the behaviour conditions having resulted in this threshold, and rejected for these conditions in the opposite case, c) the cathodoluminescence value produced on a second sample is measured by electronic shots taken in the same conditions as in step b), the component is accepted for all the behaviour conditions corresponding to thresholds greater than the value measured, and is rejected for all the behaviour conditions corresponding to thresholds less than the value measured. d) step c) is repeated on other second samples on a specific basis or by sampling.
Specification