Quantum Composers White Paper-Laser Control Using the 9500 Series Pulse Generators

Test & Measurement * Electro-Optics * Timing * Lasers * Micromachining


Synrad Model 48 Laser Control Using the 9500 Series Pulse Generators

Summary
The 9500+ Series Pulse Generators provide a multiplex function which is ideal for
providing the necessary tickle pulse, in addition to a variety of operational modes useful
for controlling the laser.
QC Family
QC 9512+, QC 9514+, QC9518+

Introduction
Many RF excited CO2 lasers, such as the Synrad Series 48, use a PWM command signal
to control the laser energy and require a short tickle' pulse to pre-ionize the laser gas.
The tickle current keeps the laser ionized but below lasing threshold and any increase in
the pulse width provides enough energy to result in laser emission. This allows the laser
to respond predictably and almost immediately to changes in the PWM control signal.
The Series 48 specifies a 1us, 5kHz pulse to generate the tickle current. A PWM signal
from 1% to 95% controls the output power.

The 9500+ Series Pulse Generators provide a multiplex function which is ideal for
providing the necessary tickle pulse, in addition, to a variety of operational modes useful
for controlling the laser. Control of the laser is done by multiplexing two channels: One
channel is used to generate the 1us, 5kHz tickle pulse; and the second channel is used to
generate the PWM output pulse.
Enabling and disabling the second channel will enable/disable laser emission.The pulse
generator channel outputs can be operated in a number of modes (continuously, burst,
single shot, duty cycle). This allows the laser to be pulsed continuously or for a
controlled number of pulses. Individual channels may also be controlled by the gate input
for synchronizing to an external signal.
Four or eight channel pulse generators may be used to synchronize the laser to
instruments, video, and/or stages. This allows control of a complete experimental setup
from one instrument.
The figure on the following page shows a 5 kHz tickle pulse multiplexed with a PWM
pulse operated in the duty cycle mode (3 pulses on, two pulses off). The bottom pulse is a
sync signal programmed to precede the laser pulses by 30us.

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Quantum Composers, Inc.
212 Discovery Drive Bozeman, MT 59718
Toll Free: 800-510-6530 406-582-0227 FAX: 406-582-0237
http://www.QuantumComposers.com

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