1.4 Optical power capacity
1 – 9
The rise and fall time of a laser beam chopped by the shutter are ap-
plication dependent, determined by the size and profile of the laser
beam. A narrower beam will blink on and o
ff
quickly compared to
a broader beam, since the blade edge will take less time to transit a
smaller beam. Similarly, the insertion delay, i.e., the time between
initiating an open-closed transition and when the laser beam is ac-
tually switched, depends upon the beam profile and its location in
the clear aperture. In general, the insertion delay will be di
ff
erent for
opening and closing.
While it may be desirable to gently focus a laser beam through the
shutter aperture to reduce the apparent open
/
close time, it should
be noted that this speed increase comes as a tradeo
ff
with increased
sensitivity to insertion delay jitter.
1.4
Optical power capacity
The SR475 and SR476 use a thin BeCu alloy shutter blade with a
black oxide finish and are intended for use in “low-power” laser
beam applications.
The maximum power handling capability of a laser shutter depends
on wavelength, duty cycle, and many other environmental factors.
SRS does not establish optical power ratings for laser shutters; please
contact SRS if you would like to request sample shutter blades to
evaluate for your application.
1.5
Operating environment
The SR475 and SR476 Laser Shutters are designed for operation in a
clean and dry laboratory environment.
1.5.1
Dust
Both the bearing and the position detection system within the shutter
head are susceptible to impairment in a dusty environment. This can
potentially result in a fault condition, when either the blade is unable
to move to the commanded position, or when the readout system is
unable to verify that the blade is in the correct position.
Always operate the laser shutter with its outer cover in place to
minimize the potential for dust to collect inside the shutter head.
If dust contamination inside the shutter is suspected, the outer cover
can be unscrewed and dust can be
gently
blown out. Use only low-
velocity air to remove dust from the shutter head, for example a
handheld hair dryer with the heat turned o
ff
.
SR475 and SR476 Laser Shutters
