Red HeNe Laser System
12112-S01 Rev CB, August 31, 2010
Page 15
www.thorlabs.com
Part 6. Troubleshooting
6.1. Technical
Failures
Problem
Fix
No light being emanated from the
laser
Make sure that aperture is open.
Check to make sure:
•
the power supply is set to the correct voltage,
•
is plugged into a working outlet,
•
the power cord is fully seated into the power supply,
•
the phono plug is connected,
•
the 3-port, high-power plug is firmly seated into the power supply,
and
•
the aperture is open.
The laser can take up to 60 sec to begin to lase. Turning the power off then
on again can speed up the start time without damaging the laser.
Note: there
is a built in CDRH safety delay of 4 - 5 seconds.
Be sure to wait longer
than 5 seconds to turn the laser off then on.
The laser does not work and there is
something rattling around inside
the laser head tube
The glass gas tube may have broken during shipping. Please contact your
local tech support office for help.
The power supply does not turn on
The power supply Laser On
Indicator does not light
Make sure the power supply is plugged in.
There is a clicking noise in either the
power supply or laser
Arcing in the laser head or the power supply can result in a flickering laser or
the laser not igniting at all. Turn off the power and contact your local tech
support office immediately.
The laser has low output power
The laser requires 30 minutes to meet published specifications. Make sure to
let it warm up.
Make sure the laser is mounted correctly. See page 12 for proper mounting
techniques.
6.2. Application Trouble Shooting
Some sources of trouble for a HeNe laser do not come from the laser failing or being out-of-spec.
Instead, these lasers are not suited to the application. One common mis-application comes from a HeNe
laser, especially a low power one (0.5 mW) being used in a metrology application.
Environment is an important consideration as well. Dirty environments can cause the optics to become
contaminated and the power output to drop below expected levels. Unstable output beams can be caused
by noisy environments with large sources of vibrations. Proper mounting on an optical table can reduce
the effects of ambient vibrations. Temperature is also a factor. If the environment where the laser is
being used fluctuates in temperature, the output power can experience a large amplitude change. Even
blowing on the laser tube can cause the output power to fluctuate significantly.
Randomly polarized lasers are actually rapidly changing, single polarization lasers. Averaged over time,
these lasers appear as randomly polarized light. However, any polarization optics in the path (intentional
or unintentional) can cause large variations in the output power. These applications should only be used
with a polarized laser.
