THORLABS SLS203L User manual

SLS203L(/M)
Stabilized Globar IR
Light Source
User Guide

Stabilized Benchtop Globar Light Source
Table of Contents
Chapter 1Warning Symbol Definitions..............................................................................................1
Chapter 2Safety....................................................................................................................................2
Chapter 3Product Overview................................................................................................................3
3.1.Planck's Law and Blackbody Radiation ........................................................................3
3.2.Silicon Carbide Globar....................................................................................................3
3.3.Optical Configuration......................................................................................................4
3.4.Beam Profile and Divergence.........................................................................................5
3.5.Output Stabilization ........................................................................................................6
Chapter 4Operation..............................................................................................................................7
4.1.Part List ............................................................................................................................7
4.2.Setting Up on a Working Surface ..................................................................................7
4.3.Switching on the Light Source.......................................................................................8
4.4.Filter Holder .....................................................................................................................9
4.5.Front Lens Tube ..............................................................................................................9
4.6.Application Ideas...........................................................................................................10
4.7.Globar Module Replacement........................................................................................10
Chapter 5Specifications.....................................................................................................................14
Chapter 6Mechanical Drawing...........................................................................................................15
Chapter 7Certifications and Compliances.......................................................................................16
Chapter 8Regulatory...........................................................................................................................17
Chapter 9Thorlabs Worldwide Contacts..........................................................................................18

Stabilized Benchtop Globar Light Source Chapter 1: Warning Symbol Definitions
Page 1 Rev C, May 8, 2017
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

Stabilized Benchtop Globar Light Source Chapter 2: Safety
CTN002679-D02 Page 2
Chapter 2 Safety
The lamp comes with a switching power supply compatible with voltages from 100 to 240 VAC. There is no need
to change the fuse.
WARNING
Do not operate this device in explosive environments.
WARNING
Do not operate this device in wet or damp conditions.
WARNING
Do NOT look directly at the light source beam during operation. Do NOT place hand or body part in
the light beam as this may cause burning.
CAUTION: HOT SURFACE
The housing of the lamp housing can get very hot during operation.
Extensive contact may cause burning.
WARNING: HOT SURFACE
The temperature of the Globar will exceed 900˚C during operation. Always wait for at least 10
minutes for the Globar module to cool down before performing a Globar module replacement.
Always wear gloves when handling Globar modules.

Stabilized Benchtop Globar Light Source Chapter 3: Product Overview
Page 3 Rev C, May 8, 2017
Chapter 3 Product Overview
3.1. Planck's Law and Blackbody Radiation
A black body is an object that absorbs all incident electromagnetic radiation (e.g. light), no light passes through or
is reflected. However, despite the name, a black body will also emit electromagnetic radiation. The radiation of a
black body in thermal equilibrium is described by Planck’s Law:
󰇛,󰇜  2



1

 

1
Where
I is the radiated power per unit area of emitting surface per unit wavelength at temperature T ; K is the
Boltzmann constant,
h is the Planck constant, c is the speed of light.
By measuring the spectrum of the blackbody radiation, we can calculate the temperature of this black body. Fig.1
shows the radiated power per unit area I as a function of wavelength at various temperature.
Figure 1 Blackbody Radiation at Different Temperatures
In real life, broadband light sources may vary widely from the ideal black body in terms of the frequency and intensity
of the light emitted. By comparing the light source to an ideal black body at a given temperature, one can
characterize the light source by the temperature of the blackbody radiator which has the same chromaticity, which
is known as the color temperature of the light source.
3.2. Silicon Carbide Globar
The Globar is a rod of silicon carbide with >99% purity, with metallic caps which serve as electrodes for the
conduction of current through the Globar from the power source.
It comprises a high-resistance hot zone and low-resistance cold end(s). The passage of current causes the high-
resistance hot zone to heat, reaching a temperature of about 1500 Kelvin.
Figure 2 A Silicon Carbide Globar
Hot zone

Stabilized Benchtop Globar Light Source Chapter 3: Product Overview
CTN002679-D02 Page 4
At this temperature, the Globar generates light radiation mostly in the IR region. Figure 3 shows a typical output
spectrum of SLS203L measured from 400 to 5600 nm, comparing to an ideal back body radiation at 1500 K. The
actual output of SLS203L may extend to over 9000 nm.
Figure 3 Typical Spectrum of SLS203L
3.3. Optical Configuration
The SLS203L is a silicon carbide Globar light source. The Globar is placed inside the housing, it is placed at one
focus of an ellipsoid reflector. The output from the ellipsoid reflector is then collimated again with a CaF
2
collimating
lens.
Figure 4 gives an outline of the optical configuration of the SLS203L Globar light source.
Figure 4 Basic Optical Configuration of SLS203L
Glo-bar
Aluminum Ellipsoid
Reflector
CaF2 Collimating Lens

Stabilized Benchtop Globar Light Source Chapter 3: Product Overview
Page 5 Rev C, May 8, 2017
3.4. Beam Profile and Divergence
Figure 5 gives an illustration of what the beam profile of SLS203L looks like at near and far field respectively. The
near field is defined as right at the output port with the front lens tube removed. The far field is defined as 1m away
from the output port of the light source.
a. Output port of SLS203L b. 1m away
Figure 5 Beam Profiler of SLS203L at Near (a) and Far (b) Field
Figure 6 shows the typical angular distribution of the output beam from a SLS203L light source.
Figure 6 Angular Distribution of SLS203L
30 mm 500 mm

Stabilized Benchtop Globar Light Source Chapter 3: Product Overview
CTN002679-D02 Page 6
3.5. Output Stabilization
Unlike traditional light sources, the SLS203L will not suffer from a gradual decrease nor short term fluctuation in
brightness during its lifetime.
SLS203L Silicon Carbide Light Source is equipped with an internal feedback loop and therefore can ensure a
constant intensity, low noise and long life span. The principle of operation is depicted in the block diagram below.
The optical intensity is measured by an internal photodiode, which feeds its monitor signal to the controller unit.
The controller unit then adjusts the driving current of the power supply to compensate any drift or fluctuation in the
optical output.
Figure 7 Closed Feedback Loop in SLS203L

Stabilized Benchtop Globar Light Source Chapter 4: Operation
Page 7 Rev C, May 8, 2017
Chapter 4 Operation
4.1. Part List
The package contains the following items:
Figure 8 Packaging of SLS203L
1. SLS203L light source
2. Power Adaptor
3. Power Cord
4. 1.3 mm (0.050") Hex Key
5. 1.5 mm Hex Key
6. 2 mm (5/64") Hex Key
4.2. Setting Up on a Working Surface
The SLS203L light source has four non-adjustable plastic feet at the bottom. It can be placed directly onto a flat
working surfaces, as shown in Figure 9 (a). It also has two 1/4"-20 (M6) threaded mounting hole on the bottom,
which are compatible with Thorlabs standard optical posts and post holders, thus can be mounted on a breadboard
or optical as shown in Figure 9 (b).
(a) (b)
Figure 9 SLS203L Set Up on a Working Surface
1
2
3
4
5
6

Stabilized Benchtop Globar Light Source Chapter 4: Operation
CTN002679-D02 Page 8
4.3. Switching on the Light Source
After setting up the light source on a working surface, follow the steps shown in Figure 10 to switch on SLS203L.
Figure 10 Switching on the SLS203L
1. Connect the power adaptor to the 3-pin socket on the back panel of the light source;
2. Rotate the threaded cap on the connector to lock it;
3. Flip the toggle switch to turn on SLS203L.
During normal operation, the green LED on the back panel will be lit. Please allow 45 minutes warm-up time for the
light source to reach a stable state. During the warm-up, the cooling fan will start to kick in when the internal
temperature rises. After the warm-up, the cooling fan will continue to operate at a stable speed.
CAUTION: HOT SURFACE
The housing of the light source can get very hot during operation. The temperature may reach
~60°C. Avoid extensive contact with skin.
WARNING
The light source generates high power IR output. Do NOT look directly at the light source beam
during operation. Do NOT place hand or body part in the light beam as this may cause burning.