Compact Stabilized Broadband Light Sources

Stabilized Light Sources for 360 - 2600 nm, 450 - 5500 nm, or 500 - 9000 nm
Stabilized Color Temperature and Output Power
Long Lifespan: 10 000 Hours (Average)

SLS202L

Broadband 450 - 5500 nm Source with SLS202C Collimation Package (Sold Separately)

SLS201L

Broadband 360 - 2600 nm Source with Included SMA Fiber Patch Cable Connected to the Output

SLS252

Replacement Bulb for the
SLS202L(/M) Stabilized Light Source

SLS203L

Broadband 500 - 9000 nm Source with Free Space Output

Please Wait

Overview
Specs
Graphs
Pin Diagram
Bulb Replacement
Application
Feedback
Lamp Selection Guide

Key Specifications^a
Item #	SLS201L(/M)	SLS202L(/M)	SLS203L(/M)
Wavelength Range	360 - 2600 nm	450 - 5500 nm	500 - 9000 nm
Peak Wavelength^b	1000 nm	1500 nm	2400 nm
Bulb Electrical Power	9 W	7.2 W	24 W
Output Coupling	Fiber Coupled (SMA) and Free Space		Free Space
Coupled Optical Power	10 mW^c	1.5 mW^d	>1.5 W^e
Included Fiber Patch Cable	SMA to SMA, 1 m Long	Not Included^f	N/A
Output Power Stability^g	<0.05%
Output Power Drift per Hour	0.01%		0.03%
Output Power Drift per °C	0.1%
Color Temperature	2796 K	1900 K	1500 K
Color Temperature Stability	±15 K
Included Power Supply	12 V, 100 - 240 VAC (Replacement Item # DS12)		24 V, 90 - 264 VAC

Please see the Specs tab for full list of specifications.
Theoretical Value based on Blackbody Radiation
Measured with the included fiber patch cable at beginning of bulb lifetime.
Measured with Thorlabs' MZ41L1 ZrF₄ MIR patch cable at the beginning of bulb lifetime.
Measured directly at the output port with the front lens tube removed.
We recommend a mid-IR fluoride fiber patch cable or fiber bundle for this light source.
Standard deviation of optical power measured at room temperature over a 1 hour period with 1 Hz sampling rate after a 45 minutes warm-up. Please see the Graphs tab for the results of our stability testing.

Accessories

Collimation Packages
Replacement Light Bulb Modules
Extra Filter Holders
Blank Insert
Variable Attenuator Insert

Features

Broadband Light Sources for Visible Through IR Wavelengths
Constant, Stable Intensity Output
- 0.1% per °C
- 0.01% per Hour (SLS201L & SLS202L)
- 0.03% per Hour (SLS203L)
Closed-Loop Control for High Stability
- Output Power Stability: <0.05%
- Color Temperature Stability: ±15 K
10 000 Hour Average Bulb Lifespan
SMA Fiber Interface or Free Space Output
Removable Filter Holder Accepts Ø1" and Ø25 mm Filters
Compatible with 30 mm Cage System
Low-Noise Fan Cooling

Thorlabs' Stabilized Light Sources provide a constant-intensity blackbody radiation spectrum from 360 to 2600 nm, 450 to 5500 nm, or 500 to 9000 nm. An internal feedback system is employed to achieve a highly stable power output. The superior performance of Thorlabs' stabilized light sources makes them ideal for experiments that require high accuracy and stability, such as transmittance and reflectance measurements.

Each light source features an integrated filter holder and offers either a fiber-coupled output with an SMA connector [Item #s SLS201L(/M) and SLS202L(/M)] or free-space output [Item # SLS203L(/M)]. The fiber coupling package on the fiber-coupled sources can be replaced with a collimation package (sold separately) for free-space applications. The quick-release mechanism used to mount the fiber coupling package ensures coupling efficiency is maintained when replacing the fiber coupling package. Internally-threaded lens tubes can also be attached directly to the front of each light source using the SM1QAM Quick-Release Adapter for custom optical systems. The compact design of our light sources (see Specs tab) gives the user flexibility with positioning this light source on a crowded optical table. Each light source can be post mounted by using the two 1/4"-20 (M6) taps on the bottom of the device and our Ø1" posts.

The front face features four 4-40 taps (as shown in the left image below) for Ø6 mm cage rods, making this device compatible with Thorlabs' 30 mm cage system. The back face has an on/off toggle switch, power indicator LED, and power connection (see image to the bottom right). A filter holder is included with each lamp. This filter holder can accommodate Ø1" and Ø25 mm optics up to 0.31" (8.0 mm) thick, allowing bandpass filters to be placed in the light path for applications requiring constant-intensity illumination at a specific wavelength. Alternatively, a sample can be installed in the filter holder between two glass plates, allowing this light source to be used for material analysis. An included SM1RR retaining ring is used to secure the optic inside the holder. We recommend the SPW602 spanner wrench to secure the retaining ring without damaging the optic. The filter holder can be locked into place using the included hex key and a setscrew located on the side of the device (see the center image below). The light sources are also compatible with the CFH2-F filter holder (sold separately below), enabling the user to quickly change between different filters or samples. Additionally, the CFH2-V Variable Attenuator Insert can be used in place of the filter holder to partially or completely block light from passing through the aperture.

Replacement bulbs are available for all three stabilized light sources. Please see the Bulb Replacement tab for detailed instructions on how to replace the bulbs in these lamps. Be sure to purchase the appropriate collimation package and bulb module for each lamp, as they are not interchangeable. If a higher color temperature is desired, our color-balancing filters can be used to attenuate red light from the light sources while passing blue light. This results in a beam with a higher color temperature and lower total power.

Click to Enlarge

The removable filter holder (filters sold separately) allows the user to mount Ø25 mm or Ø1" optics inside the stabilized light source. The front face of the light source features four 4-40 tapped holes, making it compatible with our 30 mm cage system.

Click to Enlarge

The filter holder can be locked into place with the filter setscrew located on the side of the housing. The fiber coupling package included with the SLS201L and SLS202L sources can be quickly removed and replaced with a collimation package.

Click to Enlarge

The on/off switch, power indicator, and power input are located on the back of each light source.

Item #	SLS201L(/M)	SLS202L(/M)	SLS203L(/M)
Wavelength Range	360 - 2600 nm	450 - 5500 nm	500 - 9000 nm
Peak Wavelength^a	1000 nm	1500 nm	2400 nm
Bulb Electrical Power	9 W	7.2 W	24 W
Output Coupling	Fiber Coupled (SMA) and Free Space		Free Space
Fiber-Coupled Optical Power	10 mW^b	1.5 mW^c	N/A
Free-Space Optical Power	500 mW^d	700 mW^d	>1.5 W
Collimated Optical Power^e	60 mW	15 mW	N/A
Included Fiber Patch Cable	SMA to SMA, 1 m Long	Not Included^f
Beam Divergence without Fiber Coupler^g	8.2°	13.8°
Beam Divergence with Optional Collimator^g	2°	1.4°
Beam Diameter with Optional Collimator^h	24 mm	10 mm
Output Power Stabilityⁱ	<0.05%
Optical Power Drift per Hour	0.01% (Typical)		0.03% (Typical)
Optical Power Drift per °C	0.1% (Typical)
Color Temperature	2796 K	1900 K	1500 K
Color Temperature Stability	±15 K
Lifespan	10 000 Hours (Avg.)
Compatible Filter Size	Ø1" and Ø25 mm up to 0.31" (8.0 mm) thick
Operating Temperature	0 °C to 45 °C
Storage Temperature	-15 °C to 70 °C
Included Power Supply	12 V, 100 - 240 VAC (Replacement Item # DS12)		24 V, 90 - 264 VAC at 47 - 63 Hz
Dimensions (L × W × H)	216.4 mm × 55.0 mm x 57.5 mm (8.52" × 2.17" x 2.26")		209.1 mm × 55.0 mm x 57.5 mm (8.23" × 2.17" x 2.26")

Theoretical Value based on Blackbody Radiation
Measured with included M28L01 fiber patch cable at beginning of bulb lifetime.
Measured with Thorlabs' MZ41L1 ZrF₄ MIR patch cable at the beginning of bulb lifetime.
Measured at the output port of the light source with fiber coupler removed.
Measured with optional collimation package.
We recommend a mid-IR fluoride fiber patch cable or fiber bundle for this light source.
Half angle; design value @ 587 nm.
Measured 10 cm away from the collimation package.
Standard deviation of optical power measured at room temperature over a 1 hour period with 1 Hz sampling rate after a 45 minute warm-up. Please see the Graphs tab for the results of our stability testing.

Each spectrum below is compared to the blackbody spectrum with the equivalent color temperature. Each curve is normalized to its peak. The measured SLS202L and SLS203L spectra stop at 5500 nm due to limits in the instrument's detection range. The structures in the measured light source spectra are due to absorption from various molecules such as H₂O and CO₂. The stability graph below is a typical comparison of light source stability over time with accompanying room temperature data.

Click to Enlarge
Click for Raw Data

Click to Enlarge
A long-term time comparison between the performance of Thorlabs' SLS series of stabilized light sources and changes in room temperature.

SLS201L and SLS202L Stabilized Light Source Power Connector

Pin	Description
1	No Connection
2	No Connection
3	+ 12 V
4	Ground

SLS203L Stabilized Light Source Power Connector

Pin	Description
1	Reserved
2	Ground
3	+ 24 V

The installation instructions and video below detail the recommended procedure for replacing the bulb in the SLS201L(/M) [replacement bulb item # SLS251], SLS202L(/M) [replacement bulb item # SLS252], and SLS203L(/M) [replacement bulb item # SLS253] Stabilized Light Sources. Be sure to install the correct bulb in its corresponding lamp, as the bulbs are not interchangeable.

We strongly recommend wearing gloves when replacing the bulb to prevent skin oils from being deposited onto the bulb. If you suspect the bulb is dirty, carefully clean it with alcohol before connecting it to a power supply.

Bulb Replacement Procedure

Open the Cavity

Using a 2 mm hex key, remove the screw closest to the end of the unit on the left and right sides. Do not remove the screws closest to the fan ventilation holes.
Using the same 2 mm hex key, remove the four screws securing the cavity cover, located on the underside of the unit.

Remove the Old Bulb

Unplug the white plug that is connected to the bulb module. This plug is located on the far side of the circuit board if the output aperture of the lamp is facing to the right.
Using the 1.5 mm ball-end hex key included with each replacement bulb, remove the cap screw located about half way down on the aluminum divider that separates the PCB chamber and the bulb chamber.
Remove the old bulb by sliding the wire and attached plug out through the hole in the aluminum divider.
Note: Two aluminum dowel pins, located on either side of the bulb module, may slip out of their holes while the bulb is being removed. Be careful not to misplace them as they are needed for the new bulb installation.

Install the New Bulb

Place the two dowel pins in their corresponding holes in the new bulb module.
Slide the new bulb module in the bulb chamber, point up. Pass the wire and plug through the hole in the divider first and then insert the module. The two dowel pins should slide smoothly into the holes in the divider.
While pressing the bulb against the divider, screw the cap screw back in using the included 1.5 mm ball-end hex key.
Insert the white plug back into the circuit board and secure the cavity cover.

Reflection Spectroscopy Application

These broadband light sources can be used along with our reflection spectroscopy probes, CCD spectrometers, and fiber probe holders to take diffuse reflection, specular reflection, and color measurements.

Reflection Spectroscopy Fiber Probe Bundle

Spectrometers
Thorlabs offers several CCD-based spectrometers for use in the visible, NIR, or UV to NIR spectral ranges. The CCS100 and CCS175 operate in the 350 - 700 nm and 500 - 1000 nm spectral ranges with 0.5 nm and 0.6 nm resolution, respectively. The extended-range CCS200 operates in the 200 - 1000 nm spectral range with 2.0 nm resolution, but the UV range may be heavily attenuated when analyzing broadband spectra.

Light Sources
The SLS201L tungsten-halogen broadband fiber-coupled light source, sold below, delivers a 2796 K blackbody-type spectrum in the 360 - 2600 nm wavelength range and has active electronic stabilization for low spectral and intensity drift. Alternatively, the SLS202L light source delivers similar performance with a 1900 K color temperature and 450 - 5500 nm emission range, while the SLS203L provides free space output with a 1500 K temperature and 500 - 9000 nm emission range. We also offer fiber-coupled LEDs available with a selection of peak wavelengths or a broadband white-light emission spectraand our line of fiber-coupled laser sources offers a selection of options for intense single-wavelength illumination.

Click to Enlarge
Diffuse Measurement Taken at 45° Using RPH Holder Block

Reflection Probe Fiber Bundles
Thorlabs offers reflection probes with either high-OH or low-OH multimode fiber for wavelengths from 250 - 1200 nm and 400 - 2400 nm, respectively. Probes are available with a sample end that terminates in either a Ø1/4" probe or an SMA905 connector. We also offer Ø1/4" and SMA-terminated probes with linear fiber bundle spectrometer ends for increased spectrometer coupling efficiency for samples with low reflectance.

If the coaxial illumination provided by a reflection probe bundle is not critical, separate fiber patch cables or bundles with SMA connectors can be used for illumination and signal collection. Our large-core round bundles maximize illumination intensity, while our single-fiber multimode SMA patch cables are useful for precise illumination, or for connection to a fiber-coupled laser. We also offer round-to-linear fiber bundles, which maximize signal strength at the spectrometer.

Reflection Probe Holders
Thorlabs offers the RPS and RPS-SMA fiber probe stands (RPS-SMA shown above and to the right), which allow for precise, stable positioning of the fiber optic probe at an angle of 90° or 45° relative to the sample. The probe holder arms (also sold separately) can also be integrated into other optomechanical setups using Ø1/2" posts. Alternatively, the RPH and RPH-SMA probe holder blocks sit directly on a sample, allowing the fiber tip to be positioned close to the surface and also blocking out room lights from the area under test.

Posted Comments:

user (posted 2022-12-06 10:31:51.93)

Dear Sir or Madam, could you please recommend me proper safety goggles for the use of SLS203L/M. Due to the wide wavelength range I have no idea, which is the best solution. Kind regards

cdolbashian (posted 2022-12-15 02:52:27.0)

Thank you for contacting Thorlabs. LG11 offers the best coverage for the wavelengths used in this light source.

cdolbashian (posted 2022-12-15 02:52:27.0)

Thank you for contacting Thorlabs. LG11 offers the best coverage for the wavelengths used in this light source.

Chaman Gupta (posted 2022-06-17 12:11:29.753)

Is the SLS201L NIST calibrated? If not, is there any other lamp that is NIST calibrated?

cdolbashian (posted 2022-06-21 08:42:57.0)

Thank you for reaching out to us with this inquiry Chaman. These SLS* lamps are not NIST calibrated. I will contact you to discuss other options.

user (posted 2022-06-07 15:23:14.99)

Hi, I am using a SLS203L lamp; my question is in the specs a 0.03% optical power drop per hour is given: is this drop occurring in spite of the internal feedback stabilization (without stabilization it would be even higher)? Also, if the lamp operates in a hot environment (warmer than lab conditions, say 30-35°C) what do I expect as a response, should the lamp decrease or increase its power output? Can a large external fan help in cooling it down a bit?

cdolbashian (posted 2022-06-17 04:46:39.0)

Thank you for contacting Thorlabs. There is a built-in closed-loop feedback in SLS203L to stabilize the intensity of the bulb. "0.03% per Hour" means a maximum increase/decrease of 0.03% over a stable baseline. The stability spec is only valid after the light source reaches a thermal equilibrium. 30-35°C is within the operating temperature range of the SLS203L. Between power cycles or when there is a temperature change in environment, the light source may drift and stabilize on a different equilibrium, causing a change in the mean power output. To minimize the power drift, thermal equilibrium and thermal management are required.

Shree Krishnamoorthy (posted 2021-09-20 12:22:26.143)

Dear Thorlabs team, I am interested in 2-2.5 um band. I wanted to know which of the 201/202 and 203 had the most power on that band. Also, if it was 203, could I fiber couple the same? Thanks Shree

YLohia (posted 2021-10-11 02:51:08.0)

Hello Shree, thank you for contacting Thorlabs. The SLS202L is recommended for this wavelength range when coupling into a fiber. This source is specifically designed to work with the MZ41L1 ZrF4 MIR Patch Cable. The SLS203L has a fairly large emitter size and, thus, is not suitable for fiber coupling applications.

Yohei Nagai (posted 2021-07-16 14:19:23.17)

Lifespanに関して質問があります。 Lifespanが10000H（Average）と記載されていますが、10000H後の特性が知りたいです。連続使用の場合、光源の初期強度を100％としたときに光源強度が90％まで劣化するまで何時間くらい掛かりますか？ I have a question about Lifespan. Lifespan is described as 10000H (Average), but I would like to know the characteristics after 10000H. In the case of continuous use, how long does it take for the light source intensity to deteriorate to 90% when the initial intensity of the light source is 100%?

YLohia (posted 2021-07-21 03:31:42.0)

Thank you for contacting Thorlabs. When the bulb is close to its end of life, the color temperature will be significantly lower (and thus, the spectrum will also be quite different). Unfortunately, we currently do not have sufficient data to empirically specify the end of life characteristics. A very rough estimation for a 10% intensity drop from its initial power is around 2000 to 3000 hours.

Guillermo Salceda Delgado (posted 2019-08-08 11:40:18.83)

It is just a question, Is it possible to couple the light from this white source to a single mode fiber instead of multimode fiber?

YLohia (posted 2019-08-08 01:57:05.0)

Hello, thank you for contacting Thorlabs. Unfortunately, since this cannot be considered a point source (and is highly divergent), the coupling efficiency into a few um core size single mode fiber is going to be very low (< 1%).

user (posted 2019-03-26 12:59:16.753)

Hi, What a pinhole size is used in the SLS201C collimation package? Thanks.

YLohia (posted 2019-03-26 02:59:28.0)

Hello, the pinhole diameter used is 1mm.

abc124771 (posted 2019-02-03 22:21:34.577)

Can you please tell the specs of the collimating lens that's inside the light source main body of SLS202L/M?

nbayconich (posted 2019-02-06 11:20:07.0)

Thank you for contacting Thorlabs. The collimating lens in SLS202L/M is a calcium flouride lens, part number LA5370 while the focusing lens is LB5774. I will reach out to you directly.

abc124771 (posted 2018-12-03 09:01:14.84)

Could you please tell the coherence length of SLS202L/M and also how I could calculate it myself?

YLohia (posted 2018-12-03 12:47:57.0)

Hello, thank you for contacting Thorlabs. The SLS202L is an incoherent source so there is no coherence length and, thus, cannot be calculated.

iu (posted 2018-09-20 10:40:52.67)

Hello, Can you please tell me which one from these sources has maximum output power in the range from 1 µm up to 2 µm? (Comparison between all 3 sources using the same outcoupling: lenses, filters, fibers, etc.)

YLohia (posted 2018-09-20 10:10:43.0)

Hello, thank you for contacting Thorlabs. This can be found by using the raw data supplied in the "Graphs" tab and finding the area under the curve after undoing the normalization using the specified total power output from the bulb. For the 1-2um region, the SLS203L will produce the most power, followed by the SLS201L producing slightly more than half of that.

jeremie.dain (posted 2017-08-19 06:48:52.9)

Hi, Can you check the coupled power with M96L and M15L fibers?

tfrisch (posted 2017-08-28 11:19:08.0)

Hello, thank you for contacting Thorlabs. A very rough estimate would equate the power ratio to the core area ratio which would yield under 1mW coupling efficiency. I will reach out to you directly about how to better estimate the coupled power.

guillaume.paradis (posted 2017-08-11 14:21:35.75)

Would it be possible to get a power spectral density for this product? (dBm/nm). Also is it possible to get other kind of fiber adapter (FC for example)

tfrisch (posted 2017-08-16 06:40:11.0)

Hello, thank you for contacting Thorlabs. The reason we use arbitrary units for the power is because it will depend on the core size of the fiber used or whether it is coupled to freespace. We list the raw data normalized, so to convert, you would just multiply every cell by the total power you measure through your fiber in mW and divide by the sum of the column with normalized units. You could then convert that to dBm. As for adapting to an FC fiber, the S120-SMA adapter can be unscrewed and replaced with S120-FC or another fiber adapter with internal SM1 threads. I will reach out to you directly to discuss this as well.

p.blasco (posted 2017-02-07 04:51:45.357)

I have the SLS203 source. Since the source is until 9000 nm, does it is possible to have the measured spectrum until this wl?

tcampbell (posted 2017-02-07 09:32:48.0)

Response from Tim at Thorlabs: the detector used to measure the spectral power data is only optimized for wavelengths up to 5500 nm. However, the SLS203L will behave similarly to a black body at 1500 K for wavelengths up to 9000 nm. The 1500 K black body spectral data is available by clicking the Raw Data link underneath the SLS203L Spectral Power Distribution plot in the Graphs tab.

samzlemieux (posted 2016-09-27 16:18:41.753)

I have an SLS201. I wanted to download the spectral power distribution from the Thorlabs website, but the product was discontinued. Can you send me the spectral power distribution of the SLS201?

jlow (posted 2016-09-29 11:36:37.0)

Response from Jeremy at Thorlabs: The SLS201 and SLS201L uses the same bulb and optic so you can use the spectral power distribution data for the SLS201L on the website.

tfrisch (posted 2016-08-25 09:02:34.573)

Hello lleclair, thank you for contacting Thorlabs. The spectrum listed is for the bulb and a collimating lens necessary to use our Optical Spectrum Analyzer. I have contacted you with more details. -Tyler at Thorlabs USA

lleclair (posted 2016-08-02 14:53:16.08)

The emission spectrum shown can't be correct for a quartz halogen lamp, H2O and CO2 alone in the air cannot account for the apparent spectral features. I think the emission spectrum shown must be after light has traveled though the fiber optic. Can you please provide an emission spectrum for the SLS201L that shows the output of the source only, without any attachments, fiber optics or collimator?

jonathan.rasson (posted 2015-12-17 22:43:38.42)

Hello, like hyunhuh I'm interest in data concerning the power density depending on the wavelength. Would it be possible to obtain any information about this?

besembeson (posted 2015-12-21 06:33:43.0)

Response from Bweh at Thorlabs USA: We don't currently have this data, but we are working on this and will publish on the website once we complete the measurements.

hyunhuh (posted 2015-11-09 15:22:02.347)

I wonder if you could get a graph, spectral power density (mW/nm) vs wavelength.

smcelwee (posted 2015-11-16 11:25:34.0)

Response from Sean M at Thorlabs USA: Thank you for your inquiry. I'm currently looking into your request and will contact your directly to discuss this further.

cristina.roisorza (posted 2015-09-25 12:38:45.94)

Hello. I contact again because we have not had any answer yet. we really need a broadband source for measuring fiber optic devices with an OSA (1200 - 1700 nm). Could you tell the energy level for the SLS201 if we work with a single mode fiber (G652D). Thank you very much CRO

cristina.roisorza (posted 2015-09-11 14:31:32.833)

Hello. I need a broadband source for measuring fiber optic devices with an OSA (1200 - 1700 nm). The SLS201 is very promising, but could you tell the energy level for the mentioned interval if we use a single mode fiber (G652D). Thank you CRO

besembeson (posted 2015-09-28 01:54:28.0)

Response from Bweh at Thorlabs USA: The SLS201 was designed for use with our OSA200 series with free space and multimode fiber coupling. In general, I expect that you would have very low coupling efficiency to a single mode fiber with a broadband source such as the SLS201 which may not be suitable for your OSA. We plan on doing some tests with our OSAs from SLS201 source coupled to a single mode fiber and I will follow-up with you once we have the data. For now, I would recommend our broadband SLDs if the wavelength span is enough for your application: http://www.thorlabs.hk/newgrouppage9.cfm?objectgroup_id=1760

malleblas (posted 2015-08-11 00:12:41.99)

I am wondering if it is possible to vary the lamp temperature. I want to use this for a quick cross check verification of radiation thermometers in-situ against a calibrated reference radiation thermometer.

jlow (posted 2015-08-25 03:22:35.0)

Response from Jeremy at Thorlabs: Unfortunately the lamp temperature cannot be changed.

jma215 (posted 2015-06-02 11:53:06.63)

I am interested in the SLS201 with collimation package, and in my set up would need to narrow the beam to a diameter of about 2mm. What would you recommend to do this, while minimizing beam divergence?

besembeson (posted 2015-08-28 12:24:34.0)

Response from Bweh at Thorlabs USA: After you collimate the beam using the SLSC1, you can use a beam expander in reverse to make diameter smaller but note that your divergence will be increased by same reduction factor. Our UK division will followup with you.

cbrideau (posted 2014-12-02 20:36:07.73)

We had be struggling for months to find a good calibration standard for the imaging spectrometer on our Nikon A1 microscope. We just got the SLS201 and it seems to be working out fairly well. We did find the fiber coupled source a bit difficult to use with the imaging system in the microscope (loss from fiber and difficulty coupling light into microscope objective lowered signal too much) so I ended up with a direct-coupled system instead of the fiber. This worked well and gave ample signal.

cdaly (posted 2014-12-04 02:54:28.0)

Response from Chris at Thorlabs: Thank you for your feedback. If you run into anything else, please do not hesitate to contact us at techsupport@thorlabs.com

steve (posted 2014-11-17 08:58:25.92)

is SLS201 shot noise limited ?

jlow (posted 2014-11-25 11:17:46.0)

Response from Jeremy at Thorlabs: The output of the SLS is monitored by a regular photodiode and the light source is stabilized according to the feedback from the photodiode. Since the the photodiode is not temperature controlled and it is operating near room temperature, the SLS series would not be shot noise limited.

yagor (posted 2014-10-21 09:07:11.443)

Is it possible to purchase SLS201, and use SLS252 for making it SLS202 when needed?

jlow (posted 2014-10-22 02:06:14.0)

Response from Jeremy at Thorlabs: The bulbs are not interchangeable and you cannot install the SLS252 in the SLS201.

peh (posted 2014-08-08 11:33:49.46)

I am very interested in the SLS201 light source. I just want to know if it is possible to change the spectral output of the SLS201 by setting jumpers on the electrical drive board. In others words is it possible to change the lamp temperature?

jlow (posted 2014-08-11 08:57:12.0)

Response from Jeremy at Thorlabs: It's not possible to change the lamp temperature. The only way we recommend to change the spectral output would be to put filters in front.

laurent.remy (posted 2014-06-25 09:13:12.43)

Hi, Can you please give me the same information as "juliusmadrid" about the coupled power with a SMF28e+ fiber ?

pbui (posted 2014-06-27 09:45:54.0)

We will contact you to provide the experimental data.

juliusmadrid (posted 2014-05-28 03:39:51.627)

Hi, Can you check the coupled power with a SM28e+ fiber? or with Nufern S405-XP? Theoretical calculation is fine.

pbui (posted 2014-06-02 02:31:36.0)

We will contact you to provide the experimental data.

f95941056 (posted 2013-10-31 13:56:29.06)

Can you provide the typical output spectrum of SLS201 in dBm/nm scale with 50/125 MMF or SMF28e as the output fiber, so that we can compare with products from other vendors? Can users replace the bulb own their own?

jlow (posted 2013-11-07 04:23:24.0)

Response from Jeremy at Thorlabs: We have not measured the output of the SLS201 with 50µm MM fiber and SMF28e+ fiber before. We will look into measuring this and will contact you directly about this.

thomas.ellis (posted 2013-08-03 15:49:05.13)

I have the sls201 lamp source. I am using it with some 10nm filters and it is nice that those filters come with an excel file of the spectral bandpass. It would be nice if this lamp had a similar excel file. As it is I copied the displayed plot and digitized it by hand.

jlow (posted 2013-08-07 14:44:00.0)

Response from Jeremy at Thorlabs: We will contact you directly to provide the Excel file.

Below is a selection guide for all of our white-light, broadband light sources (or lamps). In addition to these sources, Thorlabs also offers unmounted white-light LEDs, white-light mounted LEDs, white-light fiber-coupled LEDs, and high-powered, white-light Solis^® LEDs.

Broadband Light Source Selection Guide
Item #	(Click to Enlarge; Not to Scale)	Emitter Type	Wavelength Range (Click for Plot)	Output Coupling	Output Power	Bulb Electrical Power	Color Temperature	Bulb Lifetime	Replacement Bulb
SLS204		Deuterium	200 - 700 nm	Free Space or Fiber Coupled (SMA)	2 mW^a 0.1 mW^b (Typ.)	30 W	N/A	2000 h^c	SLS254B
SLS205		Xenon Arc	240 - 1200 nm	Free Space or Fiber Coupled (SMA)	290 mW^a 5 mW^d (Typ.)	75 W	5800 K^a 5400 K^d	2000 h^c	SLS255B
SLS401		Xenon Arc	240 - 2400 nm	Free Space^e	>1.3 W^a	150 W	5800 K	2000 h^c	SLS401B^f or SLS402B
SLS402		Mercury-Xenon Arc	240 - 2400 nm	Free Space^e	>1.3 W^a	150 W	6000 K	2000 h^c	SLS401B or SLS402B^f
SLS302		Quartz Tungsten-Halogen	360 - 2500 nm	Free Space^e	>10 W^a	150 W	3400 K	1000 h^g	SLS301B
SLS201L(/M)		Quartz Tungsten-Halogen	360 - 2600 nm	Free Space^e or Fiber Coupled (SMA)	500 mW^a 10 mW^h	9 W	2796 K	10 000 h	SLS251
SLS301		Quartz Tungsten-Halogen	360 - 3800 nm	Free Space^e	>1.6 W^a	150 W	3400 K	1000 h^g	SLS301B
OSL2		Quartz Tungsten-Halogen	400 - 1600 nm (Typical)	Fiber Bundle	1.4 Wⁱ	150 W	3200 K	1000 h^c	OSL2B^f, OSL2B2, or OSL2BIR
OSL2IR		Quartz Tungsten-Halogen	400 - 1750 nm (Typical)	Fiber Bundle	3.8 Wⁱ	150 W	3200 K	200 h^c	OSL2B, OSL2B2, or OSL2BIR^f
QTH10(/M)		Quartz Tungsten-Halogen	400 - 2200 nm	Free Space	50 mW (Typ.)	10 W	2800 K^j (Typ.)	2000 h	QTH10B
SLS202L(/M)		Tungsten	450 nm - 5.5 µm	Free Space^e or Fiber Coupled (SMA)	700 mW^a 1.5 mW^k	7.2 W	1900 K	10 000 h	SLS252
SLS203L(/M)		Silicon Carbide Globar	500 nm - 9 µm	Free Space	>1.5 W^a	24 W	1500 K	10 000 h	SLS253
SLS303		Silicon Nitride Globar	550 nm - 15 µm	Free Space	4.5 W^a	70 W	1200 K	5000 h^g	SLS303B

Free-space optical power measured without adapters at the beginning of bulb lifetime.
Measured with Thorlabs' M114L01 solarization-resistant patch cable at beginning of bulb lifetime.
Operation time before the maximum optical output power of the bulb reaches 50% of its original output.
Measured with Thorlabs' M111L01 solarization-resistant patch cable at beginning of bulb lifetime.
Adapters are available separately to couple the free-space output into liquid light guides (LLGs).
This bulb is identical to the original bulb that comes with the light source.
Operation time before the controller cannot stabilize the output power of the bulb.
Fiber-coupled optical power, measured with included fiber patch cable at beginning of bulb lifetime.
Power at Fiber Tip at Maximum Bulb Intensity
Color temperature will vary from unit to unit.
Measured with Thorlabs' MZ41L1 ZrF₄ mid-IR patch cable at the beginning of bulb lifetime.

Stabilized Tungsten-Halogen Light Source, 360 - 2600 nm

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Simplified Optical Diagram of the SLS201L

Click to Enlarge
The SLS201L(/M) contains an N-BK7 LBF254-040 Spherical Lens and a B270 ACL2520U Aspheric Lens to couple blackbody radiation into a fiber.

360 - 2600 nm Stabilized Light Source
Includes Fiber Patch Cable and DS12 Power Supply
>10 mW Coupled Power Through Included Patch Cable
Replacement Bulb Module Sold Below

Thorlabs' Stabilized Tungsten-Halogen Light Source provides a constant-intensity, 10 mW blackbody radiation spectrum between 360 and 2600 nm. Since the blackbody spectrum spans both the visible and near-infrared spectral ranges, this source is ideal for integration into optical measurement equipment. Combine the stabilized light source with a reflection probe and spectrometer for diffuse reflection and fluorescence measurements or use it to back-illuminate a test target as part of a detector calibration system. It can also be used as an illumination source in a white light interferometer for applications such as mapping surface structure. The included filter holder is interchangeable with the CFH2-F filter holder, sold below.

The coupled output power of the SLS201L(/M) source with the included multimode SMA fiber patch cable is 10 mW. Patch cables with smaller core sizes and numerical apertures or longer fibers can be used at the expense of the output power while a larger core size or shorter fiber length can increase the output power. The S120-SMA fiber adapter on the front of this light source is removable and can be replaced with any internally SM1-threaded fiber adapter. In particular, to provide compatibility with LLGs, the SM1T1 coupler can be used with a liquid light guide (LLG) collimation adapter. Transmission of wavelengths longer than 800 nm through the LLG for longer than an hour may result in permanent damage to the LLG tip; to reduce damage during extended use, incorporate a filter to limit transmission of IR wavelengths.

Take care when removing and reinserting the fiber adapter, as it is pre-adjusted to its optimum position during manufacturing. The adapter may be loosened and adjusted using the included 30 mm hex wrench. Alternatively, the entire fiber coupling package can be replaced by the SLS201C Collimation Package (sold below) to allow this lamp to be used in free-space applications.

An internal fan keeps the light source temperature regulated. This fan is low noise and engages only when the internal temperature exceeds 65 °C. The SLS201L(/M) includes a DS12 power supply.

Stabilized Tungsten IR Light Source, 450 - 5500 nm

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Diagram Showing the internal optical elements of the SLS202L

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The SLS202L(/M) contains an LA5370 Plano-Convex Lens and an LB5774 Bi-Convex Lens to couple blackbody radiation into a fiber; both substrates are CaF₂.

450 - 5500 nm Stabilized Light Source
Includes a DS12 Power Supply
>1.5 mW Coupled Power Through Thorlabs' MZ41L1 ZrF₄ MIR Patch Cable
Recommended for Use with Our Mid-IR Fluoride Fiber Patch Cables and Fiber Bundles
Replacement Bulb Module Sold Below

Thorlabs' Stabilized Tungsten IR Light Source provides a constant-intensity blackbody radiation spectrum between 450 and 5500 nm. Since the blackbody spectrum spans the visible and mid-infrared spectral ranges, this source is ideal for integration into mid-IR measurement and analysis systems. The S120-SMA fiber adapter on the front of this light source is removable and can be replaced with any internally SM1-threaded fiber adapter. The fiber adapter is pre-adjusted to its optimum position during manufacturing. The adapter may be loosened and adjusted using the included 30 mm hex wrench. Alternatively, the fiber-coupling package can be replaced by the SLS202C Collimation Package (sold below) to allow this lamp to be used in free-space applications. A MIR fluoride fiber patch cable or fiber bundle is recommended for use with this device. The included filter holder is interchangeable with the CFH2-F filter holder, sold below.

An internal fan keeps the light source temperature regulated. This fan is low noise and engages only when the internal temperature exceeds 65 °C. The SLS202L(/M) includes a DS12 power supply.

Stabilized Globar Light Source, 500 - 9000 nm

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Simplified Optical Diagram of the SLS203L

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The SLS203L(/M) contains an LA5370 Plano-Convex Lens made from CaF₂ to collimate blackbody radiation.

Click to Enlarge
The angular power distribution emitted from the SLS203L(/M) Stabilized Globar Source.

500 - 9000 nm Stabilized Light Source
Collimated, Free Space Output
>1.5 W Power Measured Over Output Port
Includes a Universal Power Supply

Thorlabs' Stabilized Globar Light Source provides a constant-intensity, >1.5 W blackbody radiation spectrum from 500 to 9000 nm. Since the blackbody spectrum spans the visible and mid-infrared spectral ranges, this source is ideal for integration into mid-IR measurement and analysis systems. It uses a silicon carbide Globar that is housed in an ellipsoid reflector to increase the optical output. A LA5370 Plano-Convex Lens inside the main housing collimates the output light. The angular distribution of this output beam is shown in the graph to the right. The included filter holder is interchangeable with the CFH2-F filter holder, sold below.

Additionally, this light source features an internally SM1-threaded (Ø1.035"-40) lens tube at the output of the device. This tube is removable and includes an SM1RR retaining ring which can be used to secure Ø1" or Ø25 mm optics up to 18 mm thick inside it. A low-noise fan inside this light source engages when the temperature exceeds 65 °C to provide temperature regulation. The SLS203L(/M) includes a universal AC/DC power converter capable of accepting 90 - 264 VAC at 47 - 63 Hz.

Collimation Packages

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SLS201L Source with
SLS201C Collimator

Click for Details
SLS201L Beam Profile with
(A) SLS201C Collimator Only,
(B) SLS201C and DG10-600-MD Diffuser

SLS201C: Collimation Package for SLS201L(/M) Stabilized Tungsten-Halogen Light Source
SLS202C: Collimation Package for SLS202L(/M) Stabilized Tungsten IR Light Source
Collimation Packages for Previous-Generation SLS Sources

The SLS201C and SLS202C are collimation packages for the SLS201L(/M) tungsten-halogen and SLS202L(/M) tungsten IR stabilized light sources, respectively. Each unit consists of two collimating lenses and a pinhole packaged inside an internally SM1-threaded (1.035"-40) quick-release lens tube, which is engraved with the item number for easy identification. The SLS201C contains two uncoated Aspheric Condenser Lenses, while the SLS202C contains two Uncoated CaF₂ Bi-Convex Lenses.

We also offer the SLSC1 and SLSC2 Collimation Packages for our previous-generation SLS201(/M) and SLS202(/M) sources, respectively. The SLSC1 and SLSC2 collimators and not compatible with the light sources sold above.

To install, unthread the fiber adapter from the output of the light source and thread on the appropriate collimation package with the quick-release adapter facing toward the lamp. Be sure to install the correct collimation package in its corresponding lamp, as they are not interchangeable.

Please note that the output beam cannot be perfectly collimated due to the halogen lamp's incoherent emission. The SLS201C or SLS202C Collimation packages may be used directly with their respective halogen light sources (see A in photo to the right, 25 cm away from the end of the collimation package), or they may be used in conjunction with a Ø1" mounted diffuser attached to the threaded end of the collimation package (see B in photo above). The diffuser serves to smooth out the beam profile while increasing the beam divergence angle.

Item #	Compatible Stabilized Light Source^a	Beam Diameter	Half Divergence Angle	Output Power (Typ.)	Outer Dimensions	Threads on Output Port
SLS201C	SLS201L(/M)	24.0 mm^b	2.0° ^c	60 mW	Ø30.5 mm x 97.6 mm (Ø1.20" x 3.84")	Internal SM1 (1.035"-40)
SLS202C	SLS202L(/M)	10.0 mm^b	1.4° ^c	15 mW	Ø30.5 mm x 97.6 mm (Ø1.20" x 3.84")
SLSC1^d	SLS201(/M)^d	22.4 mm^e	1.3° ^f	39 mW^g	Ø30.5 mm x 35.0 mm (Ø1.20" x 1.38")
SLSC2^d	SLS202(/M)^d	16.8 mm^e	1.0° ^f	19 mW^g	Ø30.5 mm x 35.0 mm (Ø1.20" x 1.38")

Collimation packages are not interchangeable between sources.
Measured 10 cm away from the collimating lens.
Half angle, design value @ 587 nm.
These collimation packages are only compatible with our previous generation of SLS light sources.
Theoretical RMS beam diameter at 10 mm after the collimating lens in the collimation package.
Theoretically calculated using the operating wavelength ranges of the respective lamps.
Measured with a thermal sensor at the output port of the collimation package.

Replacement Light Bulb Modules

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Bulb Item #	Compatible Light Source	Bulb Type	Bulb Electrical Power	Color Temperature
SLS251	SLS201L(/M)	Tungsten- Halogen	9 W	2796 K
SLS252	SLS202L(/M)	Tungsten IR	7.2 W	1900 K
SLS253	SLS203L(/M)	Globar	24 W	1500 K

SLS251: Replacement Tungsten-Halogen Bulb for SLS201L(/M) Stabilized Light Source
SLS252: Replacement Tungsten IR Bulb for SLS202L(/M) Stabilized Light Source
SLS253: Replacement Globar for SLS203L(/M) Stabilized Light Source

The SLS251, SLS252, and SLS253 are replacement light bulb modules for the SLS201L(/M) tungsten-halogen, SLS202L(/M) tungsten IR, and SLS203L(/M) Globar stabilized light sources, respectively. Please see the Bulb Replacement tab for detailed bulb replacement instructions. Each bulb module comes with the required 1.5 mm balldriver / hex key. Be sure to install the correct bulb in its corresponding lamp, as the bulbs are not interchangeable.

Note: We strongly recommend wearing gloves when replacing the bulb in any of our stabilized light sources to prevent skin oils from being deposited onto the bulb. If you suspect the bulb is dirty, carefully clean it with alcohol before connecting it to a power supply.

Extra Filter Holder and Other Inserts

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Pushing the adjuster down on the CFH2-V quickly closes the shutter.

Inserts Compatible with Our Compact Stabilized Light Sources
SM1-Threaded Filter Holder Insert Mounts Ø1" or Ø25 mm Optics up to 0.31" (8.0 mm) Thick
Blank Plate can be Machined for Mounting Custom Optics
Variable Attenuator Insert with Adjustable Shutter

The CFH2-F Filter Holder accommodates Ø1" or Ø25 mm optics up to 0.31" (8.0 mm) thick and can be used as a replacement for the filter holders included with the light sources sold above. With multiple filter holders, filters can be quickly swapped in and out of the stabilized light sources. The optic is secured against the back lip of the mount using the included SM1RR retaining ring.

The CFH2-B Blank Plate, also purchased separately, can be used as a manual shutter or machined to suit your specific requirements. The top plate of the CFH2-F and CFH2-B feature two laser-engraved boxes for labeling and identification of the mounted optic.

The CFH2-V is a variable attenuator insert that is equipped with a black-oxide-coated variable single-blade shutter to partially or fully block light. The shutter moves vertically from the top across the Ø0.54" aperture and is intended for a maximum 0.50" beam diameter. Shutter position is controlled with a 3/16"-120 adjuster that provides 0.005" shutter translation per revolution; fine adjustments can be performed with the included 5/64" hex key. To quickly close the shutter, press the adjuster down (see photo to the right); letting go of the adjuster will return the shutter to the set position (within 0.0005"). For best performance, light after the attenuator insert should be coupled into a fiber optic patch cable as the output beam profile will not be circular. The lamp output will be clipped on the attenuator if the aperture is smaller than the beam size; therefore, the output power will be smaller even if the shutter is completely open.