Fiber And Solid Combined Picosecond Laser Regenerative Amplifier

Ultrashort pulse laser with high repetition rate,high pulse energy and picosecond pulse width is widely used in the field of physics,medicine and optical communication industry,precision machining,laser ranging,high-speed optical fiber communication technology,national defense etc.At present,the fiber laser is one of the most important parts of the laser market because of its small volume,high stability,good beam quality and high conversion efficiency,along with the traditional all solid state devices,they are used in various fields.The combination of the optical fiber and the solid ultra short pulse laser combines the comprehensive characteristics of the fiber laser and the all solid state laser,and has the advantages of compact structure,high stability,high single pulse energy and low cost,therefore,it is of great significance to carry out the study of ultrashort pulse laser with optical fiber and solid.In this paper,a detailed theoretical and experimental study is carried out.The main content is divided into the following parts:Part one,the significance and development of ultrashort pulse laser are described,the research status of high repetition rate picosecond laser regenerative amplifier is introduced.Part two,the theory of regenerative amplifier is studied,the characteristics of two kinds of gain media are studied,this paper focuses on the regenerative amplification four level laser rate equation,and gives a theoretical explanation for the period doubling phenomenon in the process of regenerative amplification,we compare two methods of end pumped and side pumped,then analyze the theory of the optical resonator in the regenerative amplifier system.Part three,the high frequency and high energy regenerative amplifier is studied.Firstly,we introduce the working principle and types of regenerative amplifier,then,according to some key problems that need to be paid attention to in the design of regenerative amplifier,we carry out the design of regenerative cavity,and select the appropriate Pockels cell and high voltage drive power.we analyze the saturation characteristics of gain medium during the regenerative amplifie in the last.An all fiber mode-locked picosecond laser is used as the front end of the regenerative amplifie,continuous pumped Nd:YAG crystal isused as solid amplification part.And we have designed the prototype according to the need.Finally,the central wavelength of 1064 nm,the repetition rate of 1-5kHz,and the stable singlepulse output are obtained.When the repetition rate is 1kHz,pulse width is 14.8ps,singlepulse energy of 1.43 mJ.When the repetition rate is 5kHz,the maximum average power is 2.5W,single pulse energy is 0.5mJ.The high repetition frequency pulse output instability are explained,the pulse frequency,round-trip lifetime life and thermal lens effect of laser crystal is a key factor affecting stability of the high frequency regenerative amplifieroutput pulse.Part four,we summarize and look forward to the study on fiber and solid combined picosecond laser regenerative amplifier.