THORLABS LCC1620A User manual

LCC1620A(/M) &
LCC1622(/M) &
LCC1623(/M)
Liquid Crystal
Shutters
User Guide

Table of Contents
Chapter 1 Safety .............................................................1
Chapter 2 Product Overview...........................................2
Chapter 3 Setup..............................................................4
Chapter 4 Operation .......................................................6
Chapter 5 Specifications and Graphs...............................8
5.1.2 Shutter Timing Specifications..................................... 10
Chapter 6 Mechanical Drawings ...................................26
Chapter 7 Maintenance ................................................ 28
Chapter 8 CE Certification.............................................29
Chapter 9 Regulatory....................................................30
Chapter 10Thorlabs Worldwide Contacts.......................32

Liquid Crystal Shutters Chapter 1: Safety
Rev. B, February 6, 2023 Page 1
Chapter 1 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 the
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 to 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.
Laser Radiation Warning
Avoid Exposure to Beam

Liquid Crystal Shutters Chapter 2: Product Overview
Page 2 CTN018794-D02
Chapter 2 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.

Liquid Crystal Shutters Chapter 2: Product Overview
Rev. B, February 6, 2023 Page 3
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.
Shipping List
•LCC1620A(/M), LCC1622(/M), or LCC1623(/M) Liquid Crystal
Shutter and Variable Attenuator
•DS12 12 VDC / 4 A Power Supply with Region Specific Power
Cord
•2 SM1CP2 Externally SM1-Threaded End Caps

Liquid Crystal Shutters Chapter 3: Setup
Page 4 CTN018794-D02
Chapter 3 Setup
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 of 5.7 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.
Power Supply
The shutter operates with a 12 V DC power and the power supply
(Item # DS12) is included with the shutter.
Powering ON the Shutter
When the shutter is connected to the power supply, it automatically
powers on. There is no additional power switch.
Beam Centering
For optimal performance, it is recommended that the beam is well
centered in the input aperture.

Liquid Crystal Shutters Chapter 3: Setup
Rev. B, February 6, 2023 Page 5
Figure 3 Liquid Crystal Shutter

Liquid Crystal Shutters Chapter 4: Operation
Page 6 CTN018794-D02
Chapter 4 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 waveplate 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 used 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 shutter 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” SMA 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.

Liquid Crystal Shutters Chapter 4: Operation
Rev. B, February 6, 2023 Page 7
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 Shutters Chapter 5: Specifications and Graphs
Page 8 CTN018794-D02
Chapter 5 Specifications and Graphs
Specifications
Item # LCC1620A(/M) LCC1622(/M) LCC1623(/M)
Operating
Wavelength Range
420 –
700 nm
700 –
1100 nm
1050 –
1700 nm
Transmission
(Avg.)a>60% >80%
Contrast Ratio
(Avg.)b8000:1 >7300:1 >23000:1
Laser Damage
Threshold (CW)
0.8 W/cm
(532 nm,
Ø0.471 mm)
- -
Laser Damage
Threshold (Pulsed)
0.4 J/cm2
(532 nm,
10 ns, 10 Hz,
Ø0.750 mm)
0.1 J/cm2
(810 nm,
7.2 ns, 10 Hz,
Ø0.216 mm)
-
Clear Aperture Ø20 mm
Surface Quality 40-20 Scratch-Dig
Max Incident Angle ±5°
Switching Speed
(Shutter Mode,
Typ.)c
Opening:
5 ms
Opening:
16 ms
Opening:
66 ms
Closing:
1 ms
Closing:
0.37 ms
Closing:
0.91 ms
Operating
Frequency Ranged0 – 50 Hz - -
Wavefront
Distortion
≤λ/4 @
633 nm - -
EXT Input SMA Connector, 0 – 5 V, 25 kΩ Input
Impedance
Power Adapter 12 VDC / 4 A with Power Cord

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Rev. B, February 6, 2023 Page 9
AC Power
Requirements 100 – 240 VAC
Mounting
Two 8-32 (M4) Threaded Holes for Post
Mounting
30 mm Cage System Compatible
Internal SM1 Threads, Ø1” Lens Tube
Compatible
Operating
Temperature 15 °C to 60 °C
Dimensions 60 mm x 60 mm x 27 mm
a. The transmission is given for linearly polarized light, with the axis of
polarization aligned to the transmission axis of the shutter.
b. The average contrast ratio is specified over the operating wavelength range.
The contrast ratio is defined as the ratio of the transmitted light when the
shutter is open by the transmitted light when the shutter is closed.
c. 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.
d. In shutter mode with a 0 – 5 V TTL signal. The shutter can be driven at
frequencies higher than 100 Hz with a reduced contrast ratio. Information
on the performance of the shutters at varying frequencies can be found in
the graphs in Figures 15, 16, and 17.

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Page 10 CTN018794-D02
5.1.2 Shutter Timing Specifications
Diagram
KeyaDescription LCC1620A(/M) Time (Typ.) (ms)
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 0.061 0.052
B→C Falling edge from 90%
to 10% 0.346 0.344 0.342
A→C
Delay between the
input pulse’s rising
edge at 90% and
shutter down to 10%
0.411 0.405 0.394
D→E
Delay between the
input pulse’s falling
edge at 10% and
initialization of the
shutter rise to 10%
2.23 1.89 1.73
E→F Rising Edge from 10%
to 90% 3.24 2.71 2.61
D→F
Delay between the
input pulse’s falling
edge at 10% and
shutter rise to 90%
5.47 4.60 4.34
a. The letters refer to the points in time shown in Figure 5.

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Rev. B, February 6, 2023 Page 11
Diagram
KeyaDescription LCC1622(/M) Time (Typ.) (ms)
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%
0.256 0.142 0.098
B→C Falling edge from 90%
to 10% 0.112 0.092 0.095
A→C
Delay between the
input pulse’s rising
edge at 90% and
shutter down to 10%
0.368 0.234 0.193
D→E
Delay between the
input pulse’s falling
edge at 10% and
initialization of the
shutter rise to 10%
9.2 6.315 6.017
E→F Rising Edge from 10%
to 90% 6.78 6.716 6.81
D→F
Delay between the
input pulse’s falling
edge at 10% and
shutter rise to 90%
15.98 13.021 12.837
a. The letters refer to the points in time shown in Figure 5.

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Page 12 CTN018794-D02
Diagram
KeyaDescription LCC1623(/M) Time (Typ.) (ms)
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%
0.52 0.39 0.24
B→C Falling edge from 90%
to 10% 0.39 0.25 0.19
A→C
Delay between the
input pulse’s rising
edge at 90% and
shutter down to 10%
0.91 0.64 0.43
D→E
Delay between the
input pulse’s falling
edge at 10% and
initialization of the
shutter rise to 10%
24 20 15
E→F Rising Edge from 10%
to 90% 42 38 25
D→F
Delay between the
input pulse’s falling
edge at 10% and
shutter rise to 90%
66 58 40
a. The letters refer to the points in time shown in Figure 5.

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Rev. B, February 6, 2023 Page 13
Figure 5 Timing of the TTL pulse (top) and the shutter
response (bottom)

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Page 14 CTN018794-D02
Graphs
Figure 6 Typical LCC1620A(/M) Shutter Transmission by EXT
Input (0 – 5 V) for Multiple Voltages and Wavelengths
under “ATTENUATOR MODE”
350 400 450 500 550 600 650 700 750 800
0
10
20
30
40
50
60
70
80
90
100
LCC1620A(/M) Transmission vs. Wavelength
0 V 0.5 V 1 V 1.5 V
2 V 2.5 V 3 V 5 V
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
LCC1620A(/M) Transmission vs. Voltage
Transmission (%)
Attenuation Voltage (V)

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Rev. B, February 6, 2023 Page 15
Figure 7 Typical LCC1622(/M) Shutter Transmission by EXT
INPUT (0 – 5 V) for Multiple Voltages and Wavelengths
under “ATTENUATOR MODE”
600 700 800 900 1000 1100 1200
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 3.5 V 4 V 4.5 V 5 V
LCC1622(/M) Transmission vs. Wavelength
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
700 nm
750 nm
800 nm
850 nm
900 nm
950 nm
1000 nm
1050 nm
1100 nm
LCC1622(/M) Transmission vs. Voltage
Transmission (%)
Attenuation Voltage (V)

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Page 16 CTN018794-D02
Figure 8 Typical LCC1623(/M) Shutter Transmission by EXT
INPUT (0 – 5 V) for Multiple Voltages and Wavelengths
under “ATTENUATOR MODE”
900 1050 1200 1350 1500 1650 1800
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 3.5 V 4 V 4.5 V 5 V
LCC1623(/M) Transmission vs. Wavelength
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
900 nm
1000 nm
1100 nm
1200 nm
1300 nm
1400 nm
1500 nm
1600 nm
1700 nm
LCC1623(/M) Transmission vs. Voltage
Transmission (%)
Attenuation Voltage (V)

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Rev. B, February 6, 2023 Page 17
Figure 9 Typical LCC1620A(/M) Shutter Transmission and
Contrast Ratio for Multiple Temperatures under “SHUTTER
MODE”
350 400 450 500 550 600 650 700 750 800
0
10
20
30
40
50
60
70
80
90
100
25 °C
40 °C
60 °C
LCC1620A(/M) Transmission
Temperature Dependence
Transmission (%)
Wavelength (nm)
350 400 450 500 550 600 650 700 750 800
0.1
1
10
100
1000
10000
100000
25 °C
40 °C
60 °C
LCC1620A(/M) Contrast Ratio
Temperature Dependence
Contrast Ratio
Wavelength (nm)

Liquid Crystal Shutters Chapter 5: Specifications and Graphs
Page 18 CTN018794-D02
Figure 10 Typical LCC1622(/M) Shutter Transmission and
Contrast Ratio for Multiple Temperatures under “SHUTTER
MODE”
600 700 800 900 1000 1100 1200
50
60
70
80
90
100
25 °C
40 °C
60 °C
LCC1622(/M) Transmission
Temperature Dependence
Transmission (%)
Wavelength (nm)
600 700 800 900 1000 1100 1200
10
100
1000
10000
100000
25 °C
40 °C
60 °C
LCC1622(/M) Contrast Ratio
Temperature Dependence
Contrast Ratio
Wavelength (nm)