THORLABS LCC1620 User manual

LCC1620(/M)
Liquid Crystal Shutter
User Guide

Liquid Crystal Shutter
Table of Contents
Chapter 1Warning Symbol Definitions..............................................................................................1
Chapter 2Safety....................................................................................................................................2
Chapter 3Product Overview................................................................................................................3
Chapter 4Setup.....................................................................................................................................4
4.1.Mounting and Alignment................................................................................................4
4.2.Power Supply...................................................................................................................4
4.3.Powering On the Shutter................................................................................................4
4.4.Beam Centering...............................................................................................................4
Chapter 5Operation..............................................................................................................................5
Chapter 6Specifications and Graphs................................................................................................6
Chapter 7Mechanical Drawing...........................................................................................................10
Chapter 8Maintenance........................................................................................................................11
8.1.Troubleshooting............................................................................................................11
Chapter 9CE Certification...................................................................................................................12
Chapter 10Regulatory...........................................................................................................................13
Chapter 11Thorlabs Worldwide Contacts..........................................................................................14

Liquid Crystal Shutter Chapter 1: Warning Symbol Definitions
Rev D, January 8, 2020 Page 1
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

Liquid Crystal Shutter Chapter 2: Safety
Page 2 CTN002190-D02
Chapter 2 Safety
Do Not Open Housing!
The Liquid Crystal Shutter has no user-serviceable parts. Service should only be performed by
trained service personnel.
All statements regarding safety of operation and technical data in this instruction manual will only apply when the
unit is operated correctly.
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this
device may not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
WARNING
Laser Radiation – Avoid Exposure to Beam

Liquid Crystal Shutter Chapter 3: Product Overview
Rev D, January 8, 2020 Page 3
Chapter 3 Product Overview
Thorlabs’ Liquid Crystal Shutters are precision, high speed shutters that are ideal as a laser switch. They consist
of a Liquid Crystal (LC) cell, an electronic controller unit, and a mechanical housing, shown below in Figure 1.
Figure 1 Liquid Crystal Shutter Block Diagram
The LC cell is sandwiched between two protective glass plates and two polarizers with crossed transmission
axes, shown below in Figure 2.
Figure 2 Liquid Crystal Cell Block Diagram
A line on the front of the housing (see Figure 3) marks the transmission axis of the shutter. Linearly polarized light
needs to be aligned with this mark for optimal shutter operation. When powered on, the LC cell is controlled by
the driving voltage, which can be controlled through the potentiometer on the top of the shutter (see Figure 4).
When fully powered, the LC cell will rotate the polarization axis of the input light by 90°, aligning it to the
transmission axis of the output polarizer and allowing it to propagate through the device without significant
attenuation. By adjusting the drive voltage, the amount of rotation can be controlled, and thus this device can also
function as a variable attenuator in addition to shutter functionality.

Liquid Crystal Shutter Chapter 4: Setup
Page 4 CTN002190-D02
Chapter 4 Setup
4.1. Mounting and Alignment
The shutter is optimized to work with an input beam that is linearly polarized with its polarization axis aligned to
the line on the front of the shutter. Both linearly polarized light and proper alignment of the polarization axis are
recommended for achieving the best performance from the shutter.
For post mounting, the shutter has two 8-32 (M4) threaded holes. They have a typical thread depth is 4.5 mm and
are offset by 90°, so that light with a vertical or horizontal polarization axis can be aligned with the shutter.
Additionally, the liquid crystal shutters are designed to be compatible with Thorlabs 30 mm cage systems. The
four 4-40 holes on the front of the shutter can also be used to mount the shutter in either a horizontal or vertical
orientation using the Thorlabs Cage System.
4.2. Power Supply
The shutter operates with a 12 VDC power and the power supply is included with the shutter.
4.3. Powering On the Shutter
When the shutter is connected to the power supply, it automatically powers on. There is no additional power
switch.
4.4. Beam Centering
For optimal performance, it is recommended that the beam is well centered in the input aperture.
Figure 3 Liquid Crystal Shutter

Liquid Crystal Shutter Chapter 5: Operation
Rev D, January 8, 2020 Page 5
Chapter 5 Operation
 Ensure that the input beam is linearly polarized and that the polarization axis is aligned with the marking
on the front of the shutter. A polarizer or wave plate can be used to ensure the polarization axis is aligned
to the shutter. For best performance, ensure the beam is at normal incidence to the shutter and is aligned
straight through the center of the LC cell.
 Connect the power supply to the shutter.
 The shutter may operate either as an on/off shutter or a variable attenuator. A slide switch on the top of
the shutter (see Figure 4) allows the user to select one of these two modes of operation. When the
“SHUTTER” mode is selected, the potentiometer is used to simply to block or transmit the beam. In this
operational mode, when the potentiometer is turned fully counterclockwise, the shutter is in the off
position, which is indicated by a red LED. Turning the potentiometer will eventually switch the shutter from
off to on. When in the on position, light is transmitted through the shutter, which is indicated by a green
LED. When the “ATTENUATOR” mode is selected, the potentiometer is used as an adjustable attenuator.
Turning the potentiometer clockwise will increase the power transmitted through the shutter. The green
LED light is always lit in “ATTENUATOR” mode.
 The LCC1620 (/M) is also designed to be controlled by an external signal. The external signal is a 0 – 5 V
DC signal input into the “EXT. INPUT” SMC connector. To use an external input in “SHUTTER” mode, the
potentiometer must be in the turned fully clockwise. Whereas, in “ATTENTUATOR” mode, the “EXT
INPUT” adds an offset to the level set by the potentiometer. Thus if the potentiometer is fully
counterclockwise, the “EXT INPUT” has no effect. The “EXT INPUT” starts to take effect when the
potentiometer is turned clockwise and takes the full effect when the potentiometer is fully clockwise.
Note: under “ATTENUATOR” mode, if the potentiometer is not turned clockwise fully, the “EXT INPUT” voltage
will not achieve full transmission. Instead it can vary from off to the attenuation level set by the potentiometer.
Figure 4 Top View of the Shutter

Liquid Crystal Shutter Chapter 6: Specifications and Graphs
Page 6 CTN002190-D02
Chapter 6 Specifications and Graphs
Item # LCC1620(/M)
Operating Wavelength Range 420 - 700 nm
Transmission (Avg.) >60%
Contrast Ratio (CR; Avg.)1 >8000:1
Laser Damage
Threshold
CW 1 W/cm2 (532 nm, Ø0.471 mm)
Pulsed 0.4 J/cm2 (532 nm, 10 ns, 10 Hz, Ø0.750 mm)
Clear Aperture Ø20 mm
Surface Quality 40-20 Scratch-Dig
Max Incidence Angle ±5°
Switching Speed
(Shutter Mode)2
Opening (Typ.) 5 ms
Closing (Typ.) 1 ms
Wavefront Distortion ≤λ/4 @ 633 nm
External Input SMC Connector, 0 - 5 V, 25 kΩ Input Impedance
Power Adapter 12 VDC / 1.25 A with Power Cord
AC Power Requirements 110 - 240 VAC, 47 - 63 Hz, 0.4 A
Mounting
Two 8-32 (M4) Threaded Holes for Post Mounting
30 mm Cage System Compatible
Ø1" Lens Tube Compatible
Operating Temperature 15 °C to 60 °C
Dimension 60 mm x 60 mm x 27 mm
Figure 5 Liquid Crystal Shutter CR and Transmittance
1 The average CR is specified over the operating wavelength range.
2 In shutter mode with a 0 - 5 V TTL input from the EXT port. Opening time is defined as the time taken for the TTL signal to fall to 10% and
the shutter transmission raise to 90% of the total transmitted power, while closing time is defined as the time taken for the TTL signal raise to
90% and shutter transmission fall to 10% of the total transmitted power.
400 450 500 550 600 650 700 750 800
0
10
20
30
40
50
60
70
80
90
100
Transmission
Contrast Ratio
LCC1620(/M) Transmission and Contrast Ratio
Transmission (%)
Wavelength (nm)
1
10
100
1000
10000
100000
Contrast Ratio

Liquid Crystal Shutter Chapter 6: Specifications and Graphs
Rev ',-DQXDU\ Page 7
Figure 6 Typical Shutter Transmission at Various Voltages
Figure 7 Typical Shutter Transmission by External Input (0 - 5 V) under “Attenuator Mode”
Note: all graphs showing CR data are shown in the base 10 logarithmic scale. All light is linearly polarized and
aligned in the direction of the transmission axis on the front surface.
350 400 450 500 550 600 650 700 750 800
0
10
20
30
40
50
60
70
80
90
100
0 V 0.5 V 1 V 1.5 V
2 V 2.5 V 3 V 5 V
LCC1620(/M) Attenuation
Transmission (%)
Wavelength (nm)
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0
10
20
30
40
50
60
70
80
90
100
500 nm
550 nm
600 nm
650 nm
700 nm
750 nm
LCC1620(/M) Transmission
Transmission (%)
Attenuation Voltage (V)

Liquid Crystal Shutter Chapter 6: Specifications and Graphs
Page 8 CTN002190-D02
Figure 8 Normalized Contrast Ratio vs. Frequency
Figure 9 Switching Time Stability

Liquid Crystal Shutter Chapter 6: Specifications and Graphs
Rev ', -DQXDU\Page 9
Shutter Timing Specifications
Diagram
Key
a
Description Time (Typ.)
25 °C 40 °C 60 °C
A→B Delay between the input pulse's rising edge at 90% and
the initialization of shutter down to 90% 0.065 ms 0.061 ms 0.052 ms
B→C Falling edge from 90% to 10% 0.346 ms 0.344 ms 0.342 ms
A→C Delay between the input pulse's rising edge at 90% and
shutter down to 10% 0.416 ms 0.404 ms 0.392 ms
D→E Delay between the input pulse's falling edge at 10%
and initialization of the shutter rise to 10% 2.23 ms 1.89 ms 1.73 ms
E→F Rising Edge from 10% to 90% 3.24 ms 2.71 ms 2.61 ms
D→F Delay between the input pulse's falling edge at 10%
and shutter rise to 90% 5.47 ms 4.60 ms 4.34 ms
a. The letters refer to the points shown on the image below.

Liquid Crystal Shutter Chapter 7: Mechanical Drawing
Page 10 CTN002190-D02
Chapter 7 Mechanical Drawing
All shutter models have an identical housings and physical dimensions. The LCC1620/M has M4 tapped holes
instead of 8-32 tapped holes.
3.14"
79.7 mm
Ø0.79"
(20.0 mm)
4-40 Tapped Holes
for 30 mm Cage System
(4 Places)
1.18"
(30.0 mm)
1.18"
(30.0 mm)
1.06"
(27.0 mm)
#8-32 Thread
Internal SM1(1.035''-40)
Threads, 0.16" Deep
#8-32 Thread
0.53"
(13.5 mm)
1.18"
(30.0 mm)
0.53"
(13.5 mm)
2.36"
(60.0 mm)
1.18"
(30.0 mm)
4-40 Tapped Holes
for 30 mm Cage System
(4 Places)
Internal SM1 (1.035''-40)
Threads, 0.16" Deep

Liquid Crystal Shutter Chapter 8: Maintenance
Rev D, January 8, 2020 Page 11
Chapter 8 Maintenance
The shutter does not require maintenance under normal operating conditions.
There are no serviceable parts in the shutter and the unit should not be opened by the user. If you suspect a
problem with your shutter, please call Thorlabs and a member of our Technical Support team will be happy to
assist you.
8.1. Troubleshooting
Problem Solutions
No Output Power
Remove the caps. In “SHUTTER” mode, adjust the knob until the LED
light is green. In “ATTENUATOR” mode, adjust the knob clockwise until
the LED light is green.
Output power can’t be
attenuated
Ensure the device is powered on. Switch to the “ATTENUATOR” mode;
adjust the knob till the LED light is green.
Output is Unstable In the “ATTENUATOR” mode, if you use the “EXT INPUT” to control the
output light power, ensure the voltage is stable.

Liquid Crystal Shutter Chapter 9: CE Certification
Page 12 CTN002190-D02
Chapter 9 CE Certification

Liquid Crystal Shutter Chapter 10: Regulatory
Rev D, January 8, 2020 Page 13
Chapter 10 Regulatory
As required by the WEEE (Waste Electrical and Electronic Equipment Directive) of the European Community and
the corresponding national laws, Thorlabs offers all end users in the EC the possibility to return “end of life” units
without incurring disposal charges.
 This offer is valid for Thorlabs electrical and electronic equipment:
 Sold after August 13, 2005
 Marked correspondingly with the crossed out “wheelie bin” logo (see right)
 Sold to a company or institute within the EC
 Currently owned by a company or institute within the EC
 Still complete, not disassembled and not contaminated
As the WEEE directive applies to self-contained operational electrical and electronic products, this end of life take
back service does not refer to other Thorlabs products, such as:
 Pure OEM products, that means assemblies to be built into a unit by the user (e. g. OEM laser driver
cards)
 Components
 Mechanics and optics
 Left over parts of units disassembled by the user (PCB’s, housings etc.).
If you wish to return a Thorlabs unit for waste recovery, please contact Thorlabs or your nearest dealer for further
information.
Waste Treatment is Your Own Responsibility
If you do not return an “end of life” unit to Thorlabs, you must hand it to a company specialized in waste recovery.
Do not dispose of the unit in a litter bin or at a public waste disposal site.
Ecological Background
It is well known that WEEE pollutes the environment by releasing toxic products during decomposition. The aim of
the European RoHS directive is to reduce the content of toxic substances in electronic products in the future.
The intent of the WEEE directive is to enforce the recycling of WEEE. A controlled recycling of end of life products
will thereby avoid negative impacts on the environment.
Wheelie Bin Logo

Liquid Crystal Shutter Chapter 11: Thorlabs Worldwide Contacts
Page 14 CTN002190-D02
Chapter 11 Thorlabs Worldwide Contacts
For technical support or sales inquiries, please visit us at www.thorlabs.com/contact for our most up-to-
date contact information.
USA, Canada, and South America
Thorlabs, Inc.
[e-mail]
[e-mail]
Europe
Thorlabs GmbH
[email protected]
France
Thorlabs SAS
[email protected]
Japan
Thorlabs Japan, Inc.
[email protected]
UK and Ireland
Thorlabs Ltd.
[email protected]
[e-mail]
Scandinavia
Thorlabs Sweden AB
[email protected]
Brazil
Thorlabs Vendas de Fotônicos Ltda.
[email protected]
China
Thorlabs China
[email protected]

www.thorlabs.com