Tsunami - Beckman Institute Laser Resource Center

Chapter 3
Laser Description
General Overview
The Tsunami laser head contains the Ti:sapphire rod and the optics that form
the resonator cavity. Elements include pump beam mirrors, rod focusing
mirrors, an output coupler (OC), a high reflector (HR), beam folding mirrors,
dispersion control elements, and tuning elements. A femtosecond (fs)-configured
system uses prisms for dispersion control whereas a Gires-Tournois
Interferometer (GTI), which also contains the HR, is the dispersion control
element in a picosecond @s)-configured system. The fs configuration uses a
slit for wavelength selection while the ps configuration uses a birefringent
filter. The laser head also houses the GTI high-voltage circuit for the ps
configuration. For your convenience, the major tuning controls are located
on top of the unit, outside the laser head.
Connections to the head include power and control from the Model 3955
electronics module, power and control from the optional Model 3930 Lok-to-
Clock" electronics module, nitrogen gas from the Model 3910 purge unit,
and cooling water from the chiller.
The Model 3955 electronics module included with the laser contains heater
and driver circuits for the mode locker and for the GTI. All indicators
and controls are located on the front panel, and three cables connect it to
the laser head input bezel: the control ribbon cable and the mode locker
and photodiode BNC cables.
The optional Lok-to-Clock system provides phase-locked loop (PLL)
stabilization of output pulses and allows you to precisely synchronize the
output pulses to either its internal 80 MHz reference source or to an external
one, such as an rf synthesizer, or to another mode-locked laser. The
Model 3930 Lok-to-Clock electronics module contains the PLL circuit and
the drive circuits for the MI HR motor drive and M4 PZT-controlled mirror
(Figure 3-3 and Figure 3-4). Two cables connect the Model 3930 to the
laser head input bezel: the control ribbon cable and the photodiode BNC
cable. The Model 3930 is the same shape and size as the Model 3955 and
should be placed under the Model 3955. Chapter 8 contains a complete
description of the Lok-to-Clock system.
The Model 3910 purge regulatorlfilter unit connects between an external
nitrogen gas supply and the laser head, and it removes dust and water vapor
from the gas and provides clean, dry nitrogen to purge the sealed laser
head. A flow gauge, flow control knob, and the gas idout connections are
located on the front panel.