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Stabilized Deuterium UV Light Source

  • 200 - 700 nm Output with Continuous UV Spectrum from 200 - 400 nm
  • Long 2000 Hour Lifespan
  • SMA905 Fiber-Coupled Output
  • Compatible with SM1 Components and 30 mm Cage Systems


Deuterium Light Source

Application Idea

SLS204 Shown with Included M114L01 Solarization-Resistant Patch Cable


Replacement Deuterium Bulb (Not to Scale)

Related Items

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deuterium lamp front
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The fiber adapter and dust cap on the output port can be removed to use 30 mm cage system components and SM1-threaded components with the SLS204.
deuterium lamp front
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The measured spectral power distribution for the SLS204 Light Source. The blue-shaded region indicates the lamp's operating wavelength range. Click here for raw data.


  • Deuterium Light Source for 200 - 700 nm
  • Stabilized 30 W Bulb Intensity Using Closed-Feedback Loop
  • 0.02% Per Hour and 0.1% Per °C Output Power Drift
  • SMA905 Fiber-Coupled Output with Dust Cover
  • Internally SM1-Threaded (1.035"-40) Aperture
  • Compatible with 30 mm Cage Systems and Ø1" Lens Tubes
  • Replacement Light Bulb Available Separately
  • Location-Specific Power Cord Included

Thorlabs' SLS204 Deuterium Light Source provides stable illumination from 200 nm to 700 nm. The strong continuous spectrum at short UV wavelengths (200 - 400 nm) makes this an ideal source for UV spectroscopy applications. A closed-loop feedback system stabilizes the 30 W bulb which is coupled into a SMA905 bulkhead for connecting to a fiber patch cable. A low-noise fan cools the light source and bulb enabling continuous operation for >50 hours (see the Graphs tab for lamp stability over time). Each SLS204 includes a location-specific power cord.

The SLS204 includes a M114L01 Solarization-Resistant Multimode Fiber Patch Cable. The light source has a typical fiber-coupled output power of 0.1 mW using the included patch cable and a typical 2 mW output power when used in a free-space configuration.

Within the light source housing is a deuterium bulb and a series of UV fused silica lenses to focus the emitted light on the fiber port. Within the bulb, an electric arc is generated that excites the gaseous deuterium causing molecular emission of a continuous UV spectrum. In addition, two other major spectrum peaks occur at 486 nm and 656 nm. The deuterium bulb in the SLS204 has a lifetime of 2000 hours. Replacement bulbs are available for purchase separately. Please see the Bulb Replacement tab for detailed instructions on how to replace the bulb in these lamps.

The SLS204 comes equipped with an SMA905 fiber adapter on the output aperture and a hinged dust cap. The adapter can be removed to expose internal SM1 (1.035"-40) threading that is compatible with other externally SM1-threaded fiber adapters. The dust cap can also be removed using the included 5/64" hex key or balldriver in order to access the two of the four 4-40 tapped holes for 30 mm cage rods that provide compatibility with 30 mm cage system components. Using the cage system, it is possible to incorporate various optic mounts that are centered along the optical center of the lamp (as seen in the image above).

Please note that the SLS204 generates high-intensity UV light. Wear appropriate eye protection and do not look directly at the output during operation. Do not place hands or body parts in the path of the beam.

Item # SLS204
Wavelength Range 200 - 700 nm
Bulb Electrical Power 30 W
Output Fiber M114L01 Patch Cable (Included)
Ø600 µm, 0.22 NA, SMA905 Connectors
Fiber-Coupled Output Powera 0.1 mW (Typical)
Free-Space Output Powerb 2 mW (Typical)
Output Power Drift 0.02% Per Hour (Typical)
0.1% Per °C (Typical)
Output Power Stabilityc <0.06%
Bulb Lifetimed 2000 h
Power Supply 100 - 240 VAC, 50 - 60 Hz
Operating Temperature 0 - 40 °C
Storage Temperature -15 - 70 °C
Dimensions (L x W x H) 246.3 mm x 170.0 mm x 129.8 mm
(9.70" x 6.69" x 5.11")
  • Measured with M114L01 Fiber Patch Cable at Beginning of Bulb Lifetime
  • Measured at the Output Port with the Fiber Adapter Removed at Beginning of Bulb Lifetime
  • Standard deviation of optical power measured at room temperature over a 1 hour period (after 45 minutes of warm-up) with a 1 Hz sampling rate.
  • Defined as the time it takes for the bulb to decrease to ≤50% of the initial output intensity at 230 nm.
SLS204 Front Panel
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SLS204 Front Panel
SLS204 Front Panel
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SLS204 Back Panel
Patch Cable Item # Wavelength Range NA Core Diameter Cladding Diameter Coating Diameter Bend Radius (Short Term) Bend Radius (Long Term)
M114L01 180 - 1200 nm 0.22 600 ± 12 µm 660 ± 6 µm 750 ± 20 µm 80 mm 159 mm
Click to Enlarge
The measured spectral power distribution for the SLS204 Light Source. The blue-shaded region indicates the lamp's operating wavelength range. The continuous spectrum of the deuterium lamp extends from 200 nm - 400 nm. Please note that the lower apparent intensity of the output is due to detection limitations from 300 to 400 nm and <225 nm.
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The output of the SLS204 over 50 hours of continuous operation. This graph does not include 45 minutes of warm-up to ignite the source and stabilize the output.
Bulb Handling
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The bulb can be held by the metal casing with gloved hands. Avoid making contact with the bulb envelope directly.

Bulb Handling

The bulbs used in a deuterium lamp operate at a very high temperature. If handled incorrectly, they will become a serious hazard to users and could potentially cause severe injury. It is critical to follow safety instructions when handling them.

The guidelines below describe correct bulb handling.

  • Any dust or grease on the bulb will compromise the integrity of the bulb envelope, increasing the chance that the bulb will burst. Clean any dirt, oil, or lint away from the bulb with alcohol and a lint free cloth or tissue.
  • Never bump, drop, apply excessive stress, or scratch the bulb. This could cause it to burst.
  • Always transport the bulb in the provided protective case or cover until installation.
  • Save the protective case or cover and packaging materials (box) for bulbs that have been used to their rated service life.
  • Always wear gloves when handling the bulb; never hold the bulb by its envelope (see photo to the right). Thorlabs offers gloves that can be used for bulb handling.
  • The bulb generates very high-intensity UV light output; wear the appropriate laser safety glasses during operation.
  • The bulb gets very hot during operation. Always wait at least 10 minutes for the bulb to cool down before handling the bulb after operation.
  • Electrostatic discharge (ESD) protection is recommended when handling the bulb.


SLS204 Bulb Installation
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Step 3: Press Clamps and Pull Connector
SLS204 Bulb Installation
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Step 2: Remove the Bulb Cover
SLS204 Bulb Installation
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Step 1: Loosen Panel Screw
SLS204 Bulb Installation
Click for Details
Step 6: Replace with New Bulb
SLS204 Bulb Installation
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Step 5: Remove Bulb from Holder
SLS204 Bulb Installation
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Step 4: Unscrew Bulb 

Bulb Installation

The instructions and photos to the right detail the recommended procedure for replacing the bulbs in the SLS204 Deuterium Light Source. Do not attempt to change the light bulb while the bulb and unit are hot. Allow at least 10 minutes after turning the lamp off before attempting to replace the light bulb.

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.

Open the Lamp Housing

  1. Use the included 2 mm (5/64") hex key to loosen the panel screw on the side of the light source.
  2. Hold the bulb cover and pull to remove it.

Remove the Old Bulb

  1. Press the two clamps on the sides of the connector at the same time and pull the connector from the socket to electrically disconnect the bulb.
  2. Use the 2 mm (5/64") hex key to remove the two cap screws holding the bulb within the lamp.
  3. Pull out the bulb by the metal housing; do not touch the bulb envelope.

Install the New Bulb

  1. Place the replacement bulb within the lamp aligning the slot in the bulb base with the pin on the front side of the bulb holder. Tighten the two cap screws with the hex key and plug in the black connector to connect the bulb. Afterwards, replace the side panel and tighten the panel screw with the hex key.

Posted Comments:
masonkn608  (posted 2019-01-02 16:24:20.267)
Can you advise a filter to remove the visible lines from the deuterium lamp SLS204, but still passs 200-400nm? Regards, Ken Mason
YLohia  (posted 2019-01-03 09:13:37.0)
Hello Ken, thank you for contacting Thorlabs. Unfortunately, we currently do not offer a short pass filter that passes the UV region and blocks the visible light. I have posted your request on our internal engineering forum for further consideration.
ktothejw  (posted 2018-07-16 22:11:31.62)
Unlike the equipment spec, the intensity is greatly reduced around 275 nm (using CCS200). If you give me mail, I will send the data together. Best regard.
YLohia  (posted 2018-07-17 08:42:59.0)
Hello, thank you for contacting Thorlabs. In general, you can reach us via email at That being said, this attenuation is to be expected when using the CCS200. For one, amplitude correction is not available below 380nm, so the spectrum curves will not be true. To add to that, a large difference in the relative response of the system from the UV to the visible inhibits reliable power readings in the UV when performing broadband measurements. Features in the UV may still be visible with the use of a bandpass or shortpass filter to prevent saturation at longer wavelengths.

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

Lamp Selection Guide
Item # (Click to Enlarge;
Not to Scale)
Emitter Type Wavelength Spectrum
Output Coupling Output Power Bulb Electrical
Lifetime Replacement
HPLS343 Plasma 350 nm -
800 nm
Liquid Light Guide 4 Wa
- 6000 Kb 10 000 hc HPLSB
HPLS345 Plasma 350 nm -
800 nm
Liquid Light Guide 7 Wa
- 6000 Kb 10 000 hc HPLSB
SLS201L(/M) Tungsten-Halogen 360 nm -
2600 nm
Fiber Coupled (SMA),
Liquid Light Guide, or Free Space
10 mWd
500 mWe
9 W 2796 K 10 000 h (Avg.) SLS251
SLS202L(/M) Tungsten 450 nm -
5500 nm
Fiber Coupled (SMA),
Liquid Light Guide, or Free Space
2 mWf
400 mWe
7.2 W 1900 K 10 000 h (Avg.) SLS252
SLS203L(/M) Silicon Nitride
500 nm -
9000 nm
Free Space >1.5 We 24 W 1500 K 10 000 h (Avg.) SLS253
SLS204 Deuterium 200 nm -
700 nm
Fiber Coupled (SMA) or Free Space 0.1 mWg,h
2 mWe
30 W N/A 2000 hc SLS254B
SLS301 Tungsten-Halogen 360 nm -
3800 nm
Free Spacei >1.6 Wh 150 W 3400 K 1000 hj (Avg.) SLS301B
SLS303 Silicon Nitride
550 nm -
15 µm
Free Space >4.5 Wh 70 W 1200 K 5000 hj (Avg.) SLS303B
SLS401 Xenon Arc 240 nm -
2400 nm
Free Spacei >1.3 Wh 150 W 5800 K 2000 hc SLS401B
SLS402 Mercury-Xenon Arc 240 nm -
2400 nm
Free Spacei >1.3 Wh 150 W 6000 K 2000 hc SLS402B
OSL2 Tungsten-Halogen 400 nm -
1300 nm
Fiber Bundle
1.4 Wk 150 W 3200 K 1000 to
10 000 h
to 50% Brightness
OSL2B2, or
QTH10(/M) Quartz Tungsten-Halogen 400 nm -
2200 nm
- Free Space 50 mWl
10 W 2800 Km (Typ.) 2000 h QTH10B
XCITE120LED LED 370 nm -
700 nm
Free Space Not Available Not Available Not Available >25 000 h Not Available
  • Measured at the output of the liquid light guide, when both the bulb and the LLG are at start-of-life.
  • Prior to LLG
  • Average lifetime of bulb, defined as the total operation time before the maximum optical output power of the bulb reaches 50% of its original output.
  • Fiber-coupled optical power, measured with included M28L01 fiber patch cable at beginning of bulb lifetime.
  • Free-space optical power, measured at the output port of the light source with the fiber coupler removed.
  • Measured with Thorlabs' MZ41L1 ZrF4 MIR patch cable at the beginning of bulb lifetime.
  • Measured with Thorlabs' M114L01 Solarization-Resistant Patch Cable at the beginning of bulb lifetime.
  • At Beginning of Bulb Lifetime
  • Liquid light guide (LLG) adapters are available separately to couple the free-space output.
  • Average lifetime of bulb, defined as the time elapsed when the controller cannot stabilize the output power of the bulb.
  • Power of Fiber Tip at Maximum Bulb Intensity
  • Measured by focusing the output beam after the ACL5040U condenser lens onto an S302C thermal power sensor with an MPD508762-90-P01 protected silver off-axis parabolic mirror.
  • Color temperature will vary from unit to unit.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SLS204 Support Documentation
SLS204Customer Inspired! Stabilized Deuterium Light Source, 200 - 700 nm
SLS254B Support Documentation
SLS254BNEW!Replacement Deuterium Bulb for the SLS204
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