Why does the existence of intermediate state in the 4-level laser can promote the production of laser beam?
A: reach population inversion between ground state and metastable state
B: reach population inversion between ground state and intermediate state
C: reach population inversion between ground state and pumped state
D: reach population inversion between intermediate state and metastable state
A: reach population inversion between ground state and metastable state
B: reach population inversion between ground state and intermediate state
C: reach population inversion between ground state and pumped state
D: reach population inversion between intermediate state and metastable state
举一反三
- In terms of land area and population, which is the biggest state and which is the smallest state in Australia?
- The ground state of carbon is ( )
- The depletion layer charge is ( ) the inversion region charge in the inversion state MOSFET. A: more than B: as same as C: less than
- The state has stopped growing in population and may not（ ） for some time.
- 为列出居住在MA或者DC州的所有的出版商，其SELECT语句的WHERE子句是（ ）。 A: WHERE State = （‘MA’，‘DC’） B: WHERE State IN （‘MA’，‘DC’） C: WHERE State BETWEEN ‘MA’ AND ‘DC’ D: WHERE State=‘MA’ AND? State=‘DC’