The Study On All-solid-state Eye-safe Nd³⁺ Lasers Based On ⁴F_3/2?⁴I_15/2 Transition

Laser operating in the wavelength region above 1.4?m have high water absorption coefficient and high eye damage threshold power,therefore we call it eye-safe laser.Eye-safe lasers have many important applications in the fields of radar,medicine and optical communications.Currently,scholars mainly using two methods to obtain eye-safe lasers.No.1:pumped laser gain mediums doped with rare earth ions such as Er3+,Ho3+,Tm3+or Nd3+,No.2:used nonlinear frequency conversion technology.We used the first method to obtain eye-safe lasers in this thesis.In the previous study of other scholars,most of them used Nd3+ doped laser crystals to obtain 1.4?m(4F3/2?4I13/2)eye-safe lasers,in fact 1.4?m laers have lower water absorption coefficient than 1.8?m lasers.In this thesis,we studied rate equation of four-level scheme,and we used AlGaAs 808nm LD as optical pumping source,Nd3+ion's 4F3/2 energy level as upper laser level,Nd3+ ion's 4I15/2 energy level as lower laser level to obtain 1.8p?m eye-safe lasers.The Nd3+ ion doped laser materials we studied including Nd:YAG crystal,Nd:LuYAG mixed crystal,Nd:LuGdAG mixed crystal,Nd:LuAG crystal and Nd:LuAG ceramic.Most of these research results were reported for the first time.Especially Nd:YAG crystal showed the best laser performance compared with other Nd3+ doped laser materials.Both of these lasers performance have relatively great quantum defect,generate high thermal effects.So we also studied sloid laser materials' thermal effect based on heat conduction equation.We used MATLAB to simulate the thermal effects on laser materials in different circumstances including different crystal length,different laser wavelength,different thermal conductivity and different pump beam size.In this thesis,we used Nd3+ crystals obtained 1.8p,m laser fill the gap between Er3+1.6?m laser and Tm3+ 2?m laser.1.8?m lasers have a potential applicatiol value.