qutools quED User manual
1 quED: Entanglement
Demonstrator Manual
1.1 Quickstart Manual
Figure 1.1: The two main components of the quED and how they are displayed in
schematics.
1.1.1 Safety instructions
Please read the safety instructions carefully as mistreatment might harm you or the prod-
uct irreparably.
2
1.1. QUICKSTART MANUAL
Laser Safety
This product contains Class 3B laser according to IEC 60825-1 (or EN 60825-1) Safety
Standards.
Class 3B lasers are hazardous to the eye from direct beam
viewing, and from specular reections even for short and un-
intentional exposures! Therefore it is absolutely necessary to
take overall safety measures when operating the source with
the white cover removed.
Additional Warnings
The following precautions should be thoroughly reviewed and followed to avoid the risk
of any damage or failure.
Avoid any back-reection into the aperture of the laser head. Permanent damage
to the laser diode can occur.
Never connect or disconnect the cable between the quCR control unit and the source
while the laser is switched on. This can lead to laser hazard for the operator and
possible permanent damage to the laser diode.
The lifetime of the laser diode can be signicantly shortened by applying the driving
currents higher then the limiting value preset in the quCR control unit. Therefore,
the laser diode should be operated strictly below this value.
Make sure to always turn o the laser diode (red push button) prior to turning o
the quCR with the key switch. Otherwise, permanent damage can occur to the laser
diode.
ESD (electrostatic discharge) sensitive device! Electrostatic charges as high as sev-
eral thousand volts might readily accumulate on the human body and equipment
and can easily discharge. If this happens in the immediate vicinity of the laser
diode, its permanent damage can occur. Therefore, proper ESD precautions are
strongly recommended when handling and operating the source. These include
avoiding wearing clothes, which easily generate ESD, putting on work gloves to pro-
tect against static electricity, maintaining environmental humidity 4050% or more,
wearing an anti-static-wristband, etc.
Opening or removing the housing of the laser head might expose the user to the
danger of laser radiation, and might cause the laser diode failure.
www.qutools.com
quED Manual V2.0
Page 3
1.1. QUICKSTART MANUAL
1.1.2 Starting up
waveplate and
magnetic interlock longpass lter
(pump block) slot for alignment plate
pump and source
beam folding
mirror
polarizer in
rotation mount
longpass lter
ber coupler
polarization maintaining
longpass lter
ber
Be careful NOT to move the adjusting knobs of the mirror mounts and the ber
couplers when unpacking the breadboard!
Plug the bers into the quCR control unit.
Connect the Laser unit to the quCR control unit using the included SUB-D9 cable.
Make sure the half waveplate is unpacked and inserted into the beam path properly.
You can access the waveplate by removing the small round cover in the white source
enclosure. Please note that removing the cover will activate the safety interlock and
shut o the laser, if it was turned on.
Make sure the polarizers are both inserted securely in the two beam paths of the
optical setup. If you have the motorized version, please note that the third motor
position in the left beam path of the quED can only be used by a horizontally
mounted motor! Vertically mounted motors can only be xed in the other two
positions.
Probably the system will have to be slightly readjusted. For this purpose, set both
polarizers to
45◦
and the integration time to 0.1 s. Keep the laser diode covered
under the white housing and turn on the laser. Set the operating current specied
in the inspection data sheet.
A small coincidence rate should already be visible. Otherwise, you have to refer
to the complete alignment procedure in the operation manual. Make sure, the
coincidence rate is not comprised of accidental coincident events only. A rate of a
few hundred per second is usually ne and enough to start with.
www.qutools.com
quED Manual V2.0
Page 4
1.1. QUICKSTART MANUAL
Maximize the single count rates and the coincidences by
carefully
adjusting the
four knobs of the two ber couplers. Do not touch the knobs of the mirror mounts.
The maximal count rate should lie within a
±180◦
turn of the knobs. Only slightly
turn the knobs remembering the starting positions and make sure you never loose
the coincidence rate completely.
Set the polarizers to
45◦/−45◦
, The coincidence rate should drop close to zero.
Congratulations, you can now use the Entanglement Demonstrator.
For environmental reasons, we do not print out the rest of the full manual. You can nd
the full manual and a lot more on our website at
https://qutools.com/qued/
under
Downloads & Links
.
www.qutools.com
quED Manual V2.0
Page 5
Other manuals for quED
2
Other qutools Laboratory Equipment manuals
