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Quartz Tungsten-Halogen Lamp

  • Broadband Emission from Visible to NIR
  • SM2-Threaded Housing for Compatibility with Ø2" Lens Tubes
  • Post Mountable for Quick and Simple Integration



Replacement Bulb

Connects to Included
Power Supply

Application Idea

SM2T2 Lens Tube Coupler
Attaching QTH10 Lamp to
LCFW5 Filter Wheel

Related Items

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  • Broadband Emission from 400 to 2200 nm
  • Internal SM2 (2.035"-40) Threads Compatible with Our Ø2" Lens Tubes
  • Bottom-Located 8-32 (M4) Tap for Ø1/2" Post Mounting
  • Adjustable Bulb Position for Optimizing Illumination Conditions
  • Includes Condenser Lens, SM2-Threaded End Cap, and Universal Power Supply
  • Replacement Bulbs Available

Thorlabs' Quartz Tungsten-Halogen Lamp is a versatile general-purpose light source for alignment, testing, and illumination needs. Packaged in a compact Ø2.20" (Ø55.9 mm) housing with a built-in heat sink, it contains internal SM2 (2.035"-40) threading on both sides for direct compatibility with our Ø2" lens tube accessories, as well as an 8-32 (M4) tap for use with our Ø1/2" posts.

With broadband emission in the visible and NIR spectral ranges, this incoherent light source is ideal for aligning a wide range of setups without introducing laser light. It can also be used in combination with a CCD Spectrometer to characterize lenses, filters, or other optical elements.

This white-light lamp ships ready for use with two externally SM2-threaded end caps and a condenser lens (Item # ACL5040U) that has been mounted in an internally-threaded SM2 housing using an SM2RR retaining ring. The front cap is knurled for easy removal by hand, while the back cap can be removed with a SPW909 or SPW801 spanner wrench (not included). A setscrew that accepts a 0.05" hex key (included) is exposed when the rear cap is removed, allowing the bulb's receptacle to be adjusted to maximize imaging quality and light collection without having to remove the condenser lens or other attached optics. The receptacle's vertical adjustment range is 0.15" (3.8 mm). To power the bulb, a universal power supply (90 - 264 VAC) with plugs for all regions is included. Replacement bulbs (Item # QTH10B) are available below.

Please note that the lamp should not be operated without the rear end cap and condenser lens, as the bulb's surface will be hot to the touch. After warming up, the heat sink will reach a temperature of 50 °C.

If your application would benefit from stabilized output power or a stabilized spectrum, we also offer a Benchtop Quartz Tungsten-Halogen Source as well as Compact Fiber-Coupled Broadband Light Sources. If a higher color temperature is desired, our color-balancing filters can be used to attenuate red light from the QTH10(/M) light source while passing blue light. This results in a beam with a higher color temperature and lower total power.

Optical Output Powera 50 mW (Typical)
Bulb Type Quartz Tungsten-Halogen Bulbb
Color Temperature 2800 K (Typical)c
Lifetime 2000 Hours
Bulb Voltage 12 VDC
Bulb Power 10 W
Bulb Socket G4 2-Pin Baseb
Included Power Supply Input: 90 - 264 VAC, 50 - 60 Hz
Output: 12 VDC
Output Connector: 2.1 mm ID x 5.5 mm OD x 9.5 mm Long (Female)
  • Measured by focusing the output beam after the ACL5040U condenser lens onto a thermal power sensor with a Ø2", 90° protected silver off-axis parabolic mirror (6" reflected focal length).
  • We strongly recommend wearing gloves (such as our latex or cotton gloves) when replacing the bulb in order to prevent skin oils from being deposited on the glass. If you suspect the bulb is dirty, carefully clean it with alcohol before connecting to power.
  • Color temperature will vary from unit to unit.
Drawing of Lamp
Click for Details

Schematic of QTH10(/M) Lamp

Posted Comments:
user  (posted 2019-05-07 06:04:17.817)
Hi, I am interested in your QTH10/M Quartz Tungsten-halogen Lamp so I can calibrate a spectrofluorometer. However, to do this I will need the bulbs original emission spectrum/Power irradiance spectrum, can you please provide this? Cheers, Callum J
YLohia  (posted 2019-05-07 11:27:40.0)
Hello Callum, I have reached out to you directly with this information.
josh josh  (posted 2019-04-24 05:46:22.857)
Buechtemann mentioned "The spectrum supplied via graph and Excel sheet has its maximum at 621 nm". However, I cannot seem to find a spectrum of this Quartz Tungsten-Halogen Lamp on the website.
YLohia  (posted 2019-04-24 09:37:52.0)
Hello, due to the previous feedback, we noticed a discrepancy between the expected spectrum and the spectrum we had on the website. We have removed that plot until we have completed further testing across various batches.
buechtemann  (posted 2018-04-09 11:36:21.217)
The Specs indicate a color temperature of 2800 K. This number implies a maximum . of the spectral radiance at app. 1000nm. On the other hand: The spectrum supplied via graph and Excel sheet has its maximum at 621 nm. This implies a color temperature of 4666 K. This is a vast dicrepancy. Please explain
llamb  (posted 2018-07-10 09:07:02.0)
Thank you for your feedback and for pointing out this discrepancy. We are looking to update the expected Spectrum after additional testing, as the current plot of the spectrum does not match the bulb's specs. The spectrum should resemble that of a black body due to it being a Quartz Tungsten-Halogen source. I will reach out to you directly with preliminary testing done on a QTH10 lamp.
user  (posted 2018-02-13 18:57:48.7)
Is there a switch on this lamp to turn it on/off or do you just unplug/plug the connector in to turn it off/on?
tfrisch  (posted 2018-03-22 02:53:00.0)
Hello, thank you for contacting Thorlabs. This lamp is controlled just by connecting it to its power supply.
sareggeti  (posted 2018-02-06 13:35:59.6)
Can this product be used as a blackbody calibration source as a 2800K temperature blackbody? Wavelengths of interest are 550nm and 650nm. With the stabilized tungsten light source (SLS201L), a plot of spectral power distribution compared to a true blackbody is provided. Is this data available for the QTH10 light source? Thanks for your help.
tfrisch  (posted 2018-03-22 02:44:28.0)
Hello, thank you for contacting Thorlabs. QTH10 does not have a feedback loop in order o stabilize the output, so if you need a blackbody source for calibration, it will not be suitable. Whether it would be suitable as an approximation would depend entirely on the tolerances of your application, but we would not be able to guarantee it against any NIST-traceable or similar standard. I will reach out to you directly to discuss your application.
daniel.o-connor  (posted 2017-12-05 13:52:19.2)
The manual safety section states the following: "Always wear eye protection when working with the lamp." Can you recommend what we should use for eye protection with this product?
nbayconich  (posted 2017-12-28 04:43:32.0)
Thank you for your feedback. For liability reasons, please verify all laser goggle selections with your local laser safety office who would have access to the complete specs of this light source and how it will be used in your application. IR blocking glasses will be most suitable for this type of light source. I will reach out to you directly about your application.
bekker  (posted 2016-02-18 15:55:50.837)
Dear Thorlabs, how reliable is the provided spectrum? I'm considering to use the lamp as an intensity calibration source for a CCD. The absolute amount of light power is not so interesting for me, the relative power versus wavelength should be known with a few percent precision though.
besembeson  (posted 2016-03-09 01:51:09.0)
Response from Bweh at Thorlabs USA: This can be used for such an application. I will follow-up with you regarding the percentage fluctuations of the relative intensity with wavelength. However, it seems to me your application might benefit from a broadband stabilized source instead like the ones at the following link:
napoleondor  (posted 2015-12-17 18:17:46.66)
Hello, I want to exact a connector type. I'd read in specification about strange inner diameter: "Output Connector: 1 mm ID x 5.5 mm OD x 9.5 mm Long (Female)". It seems that an inner diameter (1 mm) of this connector not corresponding picture of QTH10/M. What inner diameter is correct? Nikolay Brysin
besembeson  (posted 2015-12-21 03:06:02.0)
Response from Bweh at Thorlabs USA: Thanks for pointing that out. The power supply connector barrel plug is actually 2.1mm ID x 5.5mm OD x 9.5mm Long (female). We are going to correct this on our website please.

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
Not to Scale)
Emitter Type Wavelength
(Click for Plot)
Output Coupling Output Power Bulb
Bulb Lifetime
SLS204 Deuterium 200 - 700 nm Free Space or
Fiber Coupled (SMA)
2 mWa
0.1 mWb
30 W N/A 2000 hc SLS254B
SLS401 Xenon Arc 240 - 2400 nm Free Spaced >1.3 Wa 150 W 5800 K 2000 hc SLS401B
SLS402 Mercury-Xenon Arc 240 - 2400 nm Free Spaced >1.3 Wa 150 W 6000 K 2000 hc SLS402B
HPLS301(/M) RF-Driven Plasma 350 - 800 nm Free Space 9.5 Wa (Typ.) - 6000 K 10 000 hc HPLSB
HPLS343 350 - 800 nm Ø3 mm Liquid
Light Guide
4 We (Typ.) - 6000 Kf 10 000 hc HPLSB
HPLS345 350 - 800 nm Ø5 mm Liquid
Light Guide
7 We (Typ.) - 6000 Kf 10 000 hc HPLSB
SLS201L(/M) Quartz
360 - 2600 nm Free Spaced or
Fiber Coupled (SMA)
500 mWa
10 mWg
9 W 2796 K 10 000 h SLS251
SLS301 360 - 3800 nm Free Spaced >1.6 Wa 150 W 3400 K 1000 hh SLS301B
OSL2 Typical
Fiber Bundle 1.4 Wi 150 W 3200 K 1000 to
10 000 hc
QTH10(/M) 400 - 2200 nm Free Space 50 mW (Typ.) 10 W 2800 Kj (Typ.) 2000 h QTH10B
SLS202L(/M) Tungsten 450 nm - 5.5 µm Free Spaced or
Fiber Coupled (SMA)
400 mWa
2 mWk
7.2 W 1900 K 10 000 h SLS252
SLS203L(/M) Silicon Carbide Globar 500 nm - 9 µm Free Space >1.5 Wa 24 W 1500 K 10 000 h SLS253
SLS303 Silicon Nitride Globar 550 nm - 15 µm Free Space 4.5 Wa 70 W 1200 K 5000 hh 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.
  • Total operation time before the maximum optical output power of the bulb reaches 50% of its original output.
  • Adapters are available separately to couple the free-space output into liquid light guides (LLGs).
  • Measured at the output of the liquid light guide, when both the bulb and the LLG are at start-of-life.
  • Prior to LLG
  • Fiber-coupled optical power, measured with included M28L01 fiber patch cable at beginning of bulb lifetime.
  • Total operation time before the controller cannot stabilize the output power of the bulb.
  • 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.

Quartz Tungsten-Halogen Lamp

Beam Profile of Lamp Output
Click to Enlarge

These photos were taken by orienting a gray piece of cardboard perpendicular (left) and parallel (right) to the beam. Note that the beam characteristics shown here are typical and will vary from unit to unit.

Click to Enlarge

Power Supply and Adapters Included

The QTH10(/M) Quartz Tungsten-Halogen Lamp offers broadband emission (400 - 2200 nm) with a typical optical output power of 50 mW. The included universal power supply comes with common international plug adapters and accepts 90 - 264 VAC, 50 - 60 Hz input voltages.

This lamp is not intended for use in household illumination applications.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
QTH10 Support Documentation
QTH10Customer Inspired! Quartz Tungsten-Halogen Lamp, 8-32 Tap
+1 Qty Docs Part Number - Metric Price Available
QTH10/M Support Documentation
QTH10/MCustomer Inspired! Quartz Tungsten-Halogen Lamp, M4 Tap

Replacement Bulb

The QTH10B is a replacement light bulb for the QTH10(/M) Quartz Tungsten-Halogen Lamp. Please see Section 3.4 of the QTH10(/M) instruction manual for installation instructions. For the best imaging quality, the filament should be oriented perpendicular to the optical axis. We strongly recommend the use of gloves (such as latex or cotton gloves) when replacing the bulb in order to prevent skin oils from being deposited on the glass.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
QTH10B Support Documentation
QTH10BReplacement Bulb for QTH10 and QTH10/M
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Last Edited: Nov 21, 2013 Author: Dan Daranciang