EECS  539  LASERS    

Homework  #1  Posted:                  Wednesday,  January  13  

Due:     Wednesday  January  20      Problem  #1:  

 NOTE:  Boltzmann  ratio  is  given  by  

   Problem  #2:  

 During  the  last  lecture  a  4-‐level  pumping  situation  depicted  above  in  Fig.  (a)  have  been  considered  and  the  corresponding  rate  equations  have  been  derived:  

   Consider  a  slightly  modified  situation  depicted  in  Fig.  (b)  with  a  third  relaxation  rate  directly  from  level  2  to  level  0,  with  a  downward  rate  on  this  transition  given  by  γ20N2.  Write  and  solve  the  new  rate  equations  including  this  term,  and  discuss  the  new  conditions  that  are  now  necessarily  for  achieving  population  inversion.    

Problem  #3:  

   Problem  #4:  

     

Problem  #5: