Method for preparing saturable absorber device based on black phosphorus

Abstract

The invention discloses a method for preparing a saturable absorber device based on black phosphorus. According to the method, two-dimensional layered black phosphorus, which is obtained through a mechanical stripping method or which is distributed in alcoholic solution and obtained through ultrasonic concussion, is deposited on a fiber head through a directional transfer method to be used as the saturable absorbing layer of the device. The directional transfer method may effectively and high-efficiently transfer the black phosphorus to the fiber head, prevents damage to material in a manual transferring process, may accurately locate nanoscale material, prevents blind transfer, and improves a success rate of saturable absorber preparation. The black phosphorus saturable absorber prepared through the method provided by the invention employs a transmission mode, may achieve ultrashort pulse output of lasers in near-infrared and mid-infrared wavebands, has characteristics of good performance and compatibility, and is suitable for Q regulation and mode locking of lasers and optical signal processing.

Description

technical field [0001] The invention belongs to the field of saturable absorbers of pulsed lasers, and in particular relates to a method for preparing saturable absorbers used for Q-switching, mode-locking, optical signal processing and the like in lasers. Background technique [0002] At present, the saturable absorber device mainly used in the market is the semiconductor saturable absorber mirror (SESAM), but the semiconductor saturable absorber mirror has many shortcomings that are difficult to overcome. First, SESAM requires a complex and expensive clean room-based manufacturing system with complex manufacturing processes and high costs; second, due to the inherent bandgap of III-IV semiconductors, the saturated absorption spectrum is narrow and basically limited to the near-infrared band. 1. In the far-infrared band, there is currently no SESAM available; third, the optical damage threshold of SESAM is also very low, making it difficult to apply in the field of high-pow...

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Problems solved by technology

However, so far, black phosphorus has not been successfully made into a saturable absorber and applied to fiber lasers

The main difficulties are: 1. Black phosphorus is unstable and easily denatured when exposed to the air; 2. The growth conditions of black phosphorus are far harsher than graphene, and it is currently impossible to grow large-area films by chemical vapor deposition like graphene , nanoscale black phosphorus flakes can only be obtained by mechanical stripping or liquid phase separation, and it is difficult to align and transfer them to the fiber core with a diameter of less than 10 μm

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