Two-dimensional stratified material based practical saturable absorber and production method thereof

Abstract

The invention relates to a two-dimensional stratified material based practical saturable absorber and a production method thereof, and belongs to the field of saturable absorbers of lasers. The two-dimensional stratified material based practical saturable absorber comprises a substrate, a high-reflection layer, a saturable absorption layer and a functional layer. One end face of the functional layer is connected with the saturable absorption layer, one end face of the saturable absorption layer is connected with the high-reflection layer, and one end face of the high-reflection layer is connected with the substrate. By the two-dimensional stratified material based practical saturable absorber and the production method thereof, application of the lasers, such as Q-switching, mode locking and optical signal processing, is realized. By the high-reflection layer formed by composite materials, absorption loss is reduced and reflection rate is increased, and optimal material combinations can be found in terms of different wave lengths.

Description

technical field [0001] The invention relates to a practical saturable absorber based on a two-dimensional layered material and a preparation method thereof, belonging to the field of saturable absorbers of lasers. Background technique [0002] Pulsed lasers using mode-locked or Q-switched technology have the characteristics of high peak power and narrow pulse width, and have important applications in industrial micromachining, medical treatment, scientific research on ultrafast processes, and optical communications. The technology to achieve mode locking and Q switching can be divided into two types: active and passive. Among them, the method of inserting a saturable absorbing device in the laser cavity to achieve passive mode locking and Q switching does not require external electric field or optical field modulation. It is more convenient, efficient, and inexpensive, and is a widely used method. The fiber laser mode-locking devices mainly used in the market today are base...

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Problems solved by technology

A single metal is used as the reflective layer. Although the metal reflective film has high reflectivity, it has a certain absorption capacity and affects the quality of light.

Therefore, the metal reflective film is not suitable for the high-performance laser field that requires the absorption loss of the film layer to be small; after research, it is found that the reflectivity of a single metal reflective film is often difficult to achieve the reflectivity of multi-layer all-dielectric high-reflection film and metal / dielectric reflective film , for high-reflective coatings, even if the reflectivity increases by 0.01%, it will make a great contribution to the output power. For example, the reflectivity of multi-layer all-dielectric high-reflective coatings can reach more than 99%, while it is difficult for ordinary metal coatings to achieve such a high reflection. rate; from ultraviolet to mid-infrared and other wavelengths, different wavelengths often require targeted preparation of high-performance and high-reflection films, and a single metal film is difficult to meet such requirements; and most single metal films are prone to chemical reactions in the air and deteriorate, resulting in reflection Membrane instability

[0005] 2) Most manufacturing methods require manual transfer in aqueous solution

Due to the large surface tension of water and the uncertainty of manual operation, the transfer process will inevitably destroy the integrity and continuity of graphene or other two-dimensional layered materials, resulting in low device yield

[0006] 3) The adhesion between the single metal reflective layer and the base layer, the saturated absorbing layer and the reflective layer is poor and the mechanical strength is low, and it is easy to absorb water, so the stability and life are affected

[0007] 4) In some specific occasions, the saturable absorbing layer simply uses graphene materials to obtain specific required optical performance parameters, and it is difficult to control the modulation depth and optical excitation relaxation time of the saturable absorbing material

[0008] 5) The resistance to mechanical damage and photothermal damage threshold of the saturable absorbing layer and the whole device needs to be improved

[0009] 6) Part of the transmission method is directly inserted into the cavity, which increases the loss in the cavity and is not suitable for low-gain lasers

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