High-Order Harmonic With High Flux Property And The Harmonic Generation In Solids

Dynamics of electron can be explored through the attosecond pulse which generated from the high harmonic generation（HHG）,making the attosecond pulse has popular value in condensed matter physics、light physics and atom physics.However,the energy level of attosecond pulse can be as low as pJ or nJ so far,which high limit the application of attosecond pulse as it can provide single photon effect only but no other nonlinear effect,it is so deep a need to solve this problem.Achieved the attosecond pulse by means of HHG have been proved as an effective ways,so we want to have the HHG with high energy to get an powerful attosecond pulse,this article have an introduce of an high flux HHG system which pumped by an Ti:sapphire amplifier,and based on these,we build an mid-infrared femtosecond laser system and detect HHG in solid through this laser system.Above all,we have the following result:1.We design the high flux HHG system from the theory of HHG and create this system successfully,the system have 9.3 m long and consist with 6 vacuum cavity for generation and detection.To testify this system,we recover an Ti:sapphire chirped pulse amplifier（CPA）with 3 mJ,pulse duration around 35 fs,1 kHz,an obviously signal of HHG detected from multichannel plate（MCP）,which prove this system have the ability of harmonic generation and detection.2.In order to have a more powerful driving laser,we have an optimization on our home made Ti:sapphire CPA and multichannel amplifier system,solve the problem of pointing instability and multiple-pulse.Finally we get an 25 mJ pulse energy and 27.1 fs pulse duration,the repeat frequency is 1 kHz,which corresponding to the peak power is 0.97 TW.This laser system provide the pump laser for HHG system and an mid-infrared femtosecond laser system as well.3.We use the Ti:sapphire laser system mentioned above as an driving laser for the high flux HHG system under the pulse energy of 16 mJ,as this is the first time to get HHG with so powerful laser,we have to optimize the optical design for many times and finally we achieve the holonomic signal.For further exploration,we have a comparison of intensity and divergence of HHG in different length of target,the target is pulse type with frequency of 1kHz matched with the laser and the delay or duration can be adjusted.We also study the influence of the phase matching condition as change the length of target for harmonic properties:intensity and divergence.4.Based on the Ti:sapphire laser system,we create an optical parameter amplifier（OPA）mid-infrared laser system,which include four level of nonlinear OPA,and get 150μJ at 3.6μm,the pulse duration is 95 fs.We have it to the solid HHG in ZnO and Graphene,and receive the 9^th HHG from ZnO,the even order HHG from Graphene.We also make it to MgO-doped Chirped Periodical Poled Lithium Niobate,MgO:CPPLN,and get the wavelength from 400 mm to 2400 nm white laser signal,the output power is 30 mW with conversion efficiency 46%.