We (Max, Kristian, Danyal, me) fixed the "external trigger" problem.

1.) The delay between lamp sync and Q-switch trigger was too long. The delay must be 200µs (3rd picture)! 

2.) The settings from the left Dual Timer (upper and lower part) in the ESR Laser Lab (above QuantaRay laser) were wrong and are now adjusted. Settings are depicted in the attached photos (1st and 2nd pic).

4th picture shows the pulse train of the pump laser.