Light source for the coherence radar
|
The Cr4+:YAG Laser was longitudinally pumped by a flashlamp-pumped Nd:YALO laser with a repetition
frequency up to 30 Hz. The pump-laser runs in transversal fundamental mode and could be operated in two modi:
In free-running operation the pulse duration was given by the flashlamp-pulses and amounted to 140 µs, by inserting
of a saturable absorber (Cr:YAG) into the pump laser could simple gain-switching be realized. The laser supplied
then within the flashlamp pulse three laser pulses with a pulse duration of 30 ns (FWHM) per pulse. The different
parameters are summarized in the table.
|
|
|
Free-running operation
|
Q-switch operation
|
|
Pulse energy within a flashlamp pulse
|
230 mJ
|
65 mJ
|
|
Pulse duration
|
140 µs
|
30 ns
|
|
The large spectral bandwidth results results on the gain-switching effect in this laser. The laser pulse is
completely emitted, before the spectrum constricts itself on a stationary solution. The special highlight at this
laser system is the broadband frequency doubling of the Cr:YAG laser. The maximum spectral bandwidth is more than
15 nm (FWHM) at a center wavelength around 715 nm.
|
Fig. 1 Scheme of the frequency-doubled Cr:YAG laser
|
German
