1. List at least three pumping methods.

(Answer: optical pumping, electric pumping, chemical pumping)

2. Compare diode laser puping and lamp pumping. Why diode laser pumping is usually more efficient than other pumping methods?

(Answer: diode laser pumping has much higher absortion efficiency and quantum efficiency than other pumping methos.)

3. List three methods to create laser pulses.

(Answer: gain modulate, Q-Switch and mode-locking)

4. Why mode-locking use multi-mode oscillation?

(Answer: mode-locking creates pulse whose peak value is the normal value times the number of locked modes and the pulse width is inverse proportional to the number of locked modes. So the more the modes, the sharper and stronger the laser pulse.)