Method and device for time-resolved differential confocal measurement of morphological parameters in femtosecond laser processing

Abstract

The invention relates to a femtosecond laser processing morphological parameter time-resolved differential confocal measurement method and device, and belongs to the field of femtosecond laser processing detection. According to the invention, a continuous laser differential confocal light path is utilized to carry out axial accurate positioning on the surface of a material; the method comprises the following steps: processing a material by using femtosecond laser, detecting morphological parameters of the material by using the femtosecond laser with different delay times, detecting femtosecondlaser reflection signals with different delay times by using a differential confocal light path, and demodulating the signals to obtain an axial position. The processes of continuous laser differential confocal positioning, femtosecond laser processing and delayed femtosecond laser differential confocal detection are repeated. By means of the method, the variable quantity of the axial removal quantity of the material along with time in femtosecond laser machining can be obtained, time resolution measurement of the morphological parameters of the femtosecond laser high-precision machining material is achieved, the controllability of femtosecond laser machining and the machining quality of the sample are improved, and the method has important significance in improving the femtosecond machining precision, the machining quality and the controllability of the machining process.

Description

technical field [0001] The invention relates to a time-resolved differential confocal measurement method and device for morphological parameters of femtosecond laser processing, belonging to the field of femtosecond laser processing detection. Background technique [0002] Femtosecond laser processing technology uses the tightly focused "focus" of laser pulses to interact nonlinearly with materials to induce photophysical and photochemical changes, and realizes the processing and manufacturing of micro-nano device structures, because of its high processing precision and material adaptability Wide and other significant advantages have attracted much attention. [0003] When the femtosecond laser removes the material, there is no effective monitoring method for the nonlinear effect and scale effect in the instantaneous shape change of the material, for example: when the process parameter scale, time scale and spatial geometric scale of femtosecond processing are reduced , the...

AI Technical Summary

Problems solved by technology

[0004] However, the femtosecond laser has a very short processing time for material removal, and current measurement methods cannot obtain instantaneous material shape changes. Existing measurement methods are still based on traditional measurement techniques, such as axial monitoring based on laser triangular displacement sensors, back-coherent Tomography monitoring, optical coherence tomography monitoring and other methods have resolutions at the submicron level; confocal-based measurement technology has extremely high application potential in femtosecond laser processing, confocal or differential confocal axial monitoring The means have nanometer-level axial resolution, and have high focus accuracy and measurement stability. For example, a laser micro-nano processing differential confocal online monitoring integrated method and device disclosed in patent CN108286936A solves the problem of femtosecond Drift problems during laser processing, high-precision real-time focus problems, and online detection of femtosecond laser processed samples, but the measurement object of this invention is still the sample shape on the macro time scale, and it is impossible to monitor the instantaneous shape change when the material is removed process

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