Low-oscillation dispersion mirror structure and design method thereof

Abstract

The invention discloses a design for a low-oscillation dispersion mirror structure. The structure comprises a substrate, a chirped film system structure and an ultralow-refractive-index layer. The structure is characterized in that the ultralow-refractive-index layer is additionally arranged on the top part of the chirped film system structure and is realized by an inclined deposition technology, the refractive index and thickness of the ultralow-refractive-index layer can be controlled by adjusting the rate and angle of inclined deposition, and the refractive index of the chirped film system structure can be well matched with an air layer, so that the dispersion oscillation can be greatly reduced. Due to the designed structure, the dispersion oscillations of dispersion mirrors with different bandwidths and dispersion amounts can be greatly reduced, and the dispersion mirror design needs for low loss, low oscillation and large dispersion compensation amount for pulse compression in an ultrafast laser system are well met. The low-oscillation dispersion mirror structure can be applied in the ultrafast laser system (such as a chirped pulse amplification technology and an optical-fiber laser), and is an essential dispersion compensation element in the ultrafast laser system.

Description

technical field [0001] The invention belongs to the field of ultrafast lasers, in particular to a super-low refractive index obliquely deposited SiO on the surface of an ultrashort pulse laser used for pulse compression optical elements 2 layered low-oscillation dispersion mirror structure. Background technique [0002] Dispersion mirror is a kind of dispersion compensating element, which can provide certain dispersion compensation while maintaining high reflectivity. It can replace prism pair and grating in ultrafast laser system for pulse compression. Dispersion mirrors are divided into high dispersion mirrors, low dispersion mirrors and broadband chirped mirrors. When the bandwidth of the dispersive mirror increases or the amount of dispersion increases, relatively large dispersion oscillations may be introduced. This is because in the structure of the dispersive mirror, there is a serious impedance mismatch between the chirped film system and the external medium (mainl...

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Problems solved by technology

[0003] Dispersion mirror pair is currently the most common dispersion compensation element in commercial use. The dispersion mirror pair is used by changing the reference wavelength of the dispersion mirror or using it under different incident angles, so that the oscillation period of one of the dispersion mirrors is shifted by half a period, so that the two The positive and negative values ​​of the ripples of the mirrors cancel each other out. Although the oscillation ripples of each mirror are large, the group delay dispersion curve is relatively smooth when the two mirrors are used together.

However, since the dispersive mirror pairs need to be designed and manufactured in pairs, not only the amount of design engineering is large, but also the manufacturing cost is relatively high.

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