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Compact Stabilized Broadband Light Sources
Broadband 450 - 5500 nm Source with SLS202C Collimation Package (Sold Separately)
Broadband 360 - 2600 nm Source with Included SMA Fiber Patch Cable Connected to the Output
Replacement Bulb for the
Broadband 500 - 9000 nm Source with Free Space Output
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.
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.
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.
The on/off switch, power indicator, and power input are located on the back of each light source.
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.
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A long-term time comparison between the performance of Thorlabs' SLS series of stabilized light sources and changes in room temperature.
Stabilized Light Source Power Connector
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
Remove the Old Bulb
Install the New Bulb
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.
Alternatively, if the reflection probe is not used for illumination, Thorlabs offers a wide range of broadband and single wavelength light sources that are free-space or operate with a single fiber cable output. Our free-space and liquid light guide-coupled plasma light sources offer extremely intense illumination with a blackbody-type emission spectrum. Our line of fiber-coupled laser sources offers a selection of options for intense single-wavelength illumination.
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Diffuse Measurement Taken at 45° Using RPH Holder Block
Reflection Probe Fiber Bundles
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
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.
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The SLS201L(/M) contains an N-BK7 LBF254-040 Spherical Lens and a B270 ACL2520U Aspheric Lens to couple blackbody radiation into a fiber.
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 M28L01 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 universal AC/DC power converter capable of accepting 90 - 264 VAC at 47 - 63 Hz and comes in a latchable storage case that houses everything included with this device.
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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.
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 SLSC2 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
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 universal AC/DC power converter capable of accepting 90 - 264 VAC at 47 - 63 Hz and comes in a latchable storage case that houses everything included with this device.
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The SLS203L(/M) contains an LA5370 Plano-Convex Lens made from CaF2 to collimate blackbody radiation.
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The angular power distribution emitted from the SLS203L(/M) Stabilized Globar Source.
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 and comes in a latchable storage case that houses everything included with this device.
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SLS201L Source with
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SLS201L Beam Profile with
(A) SLS201C Collimator Only,
(B) SLS201C and DG10-600-MD Diffuser
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.
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.
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Pushing the adjuster down on the CFH2-V quickly closes the 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.