RF POWER SUPPLY
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laser at 45° to the horizontal or by using two or more mirrors. Mounting the laser at 45° is often not
practical while the addition of extra mirrors in the beam path adds cost and complexity and can reduce
reliability.
Technical overview
To reduce the complexity and cost of beam delivery components, the i401 laser was designed with the
beam polarized at 45° to the base plate (see Figure 3-19 for details). This de- sign allows the use of a
simple reflective phase retarder and eliminates the need for additional mirrors or complex mounting
schemes. To use a reflective phase retarding mirror, the linearly polarized beam must make a 45° angle
with the plane of incidence as shown in Figure 3-3.
Figure 4-3
Converting 45° linear polarization to circular polarization
RF power supply
i401 lasers are driven by four compact RF modules mounted internally in the laser chassis. Each RF
module converts 48 VDC input power into a radio frequency (RF) signal that is then amplified and
routed to its corresponding electrode structure in the laser tube where it excites the gas mixture in the
tube to produce lasing.
Control circuity built into the laser interrupts operation if any critical parameter is violated. Switches and
sensors on the control board monitor various conditions and parameters that, if exceeded, pose a risk of
potential damage to the laser. Additionally, laser operation is interrupted in response to the following
conditions: (1) the electromechanical shutter is closed; (2) the Shutter Open Request input signal is
missing; (3) an over temperature or low coolant flow condition occurs; (4) the Remote Reset/Start
Request input signal is enabled; (5) the Remote Interlock input signal is missing; or (6) any fault is
present.
