An ultrashort laser pulse processing system based on injection ionization and its application

Abstract

The invention discloses an ultra-short laser pulse processing system based on injection ionization and application of the ultra-short laser pulse processing system. The system comprises a laser generating device and a laser adjusting device, the laser generating device is used for generating injection light and driving light with the time sequence and the repetition frequency meeting processing requirements, the energy of the injection light is lower than that of the driving light, the laser adjusting device is used for adjusting and focusing the injection light and the driving light, therefore, the injection light is focused on the same processing area of a sample earlier than the driving light, initial injection carriers required for processing are provided when the injection light is focused on the sample to control the processing precision, and energy is supplied to the interior of the sample when the driving light is focused on the sample to control the processing efficiency. Thesystem can separate two physical processes of free carrier generation and energy injection, thereby realizing independent control over processing precision and processing efficiency and solving the inherent contradiction between processing precision and processing efficiency in ultra-short laser pulse processing.

Description

technical field [0001] The invention belongs to the field of laser technology, and more specifically relates to an injection ionization-based ultrashort laser pulse processing system and its application. Background technique [0002] With the rapid development of ultra-short laser pulse (femtosecond, picosecond) technology, using the characteristics of ultra-short laser pulse time and super-strong peak power, the energy can be quickly and accurately concentrated in a limited area, so it is possible to achieve glass Micro-nano-scale processing of materials such as metals, ceramics, semiconductors, and polymers. Different from the generation of initial free carriers in the processing of nanosecond and continuous lasers, which will be affected by local defects in materials, the initial carriers in ultrashort laser pulse processing originate from the multiphoton ionization process, which affects the localization of materials. The structure and defects are insensitive, and the p...

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Problems solved by technology

[0003] However, ultrashort laser pulse processing also has its own limitations, mainly in the inherent limitations and contradictions in the processing accuracy (spatial resolution) and processing efficiency (maximum achievable energy density) of ultrashort laser pulses.

In terms of spatial resolution, the smallest structure that can be engraved is determined by the diffraction limit, which determines the processing accuracy; and in terms of energy density, the energy that can be delivered to the inside of the sample is limited by the impact of the transparent medium in front of the focusing spot. Due to the nonlinear absorption process of the second laser, the laser intensity in the material is limited due to this nonlinear absorption process, which produces a "self-limiting effect" on energy - the so-called "lawn mower" effect , leading to the inability to input the required energy into the material, thus affecting the processing efficiency

This makes simply increasing the energy of the input femtosecond pulses not significantly improve the processing efficiency, on the contrary will reduce the processing accuracy, so there is always a contradiction between processing efficiency and processing accuracy

[0004] In general, there are inherent limitations and contradictions in the processing accuracy and processing efficiency in the existing ultrashort laser pulse processing system, and this problem has not been well resolved

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