Mid-IR Supercontinuum Laser

  • 1.3 - 4.5 μm Wavelength Coverage (7700 - 2200 cm-1)
  • >300 mW Average Output Power
  • Single-Mode, Collimated Output Beam
  • Low Noise: 0.025% (Typical)


Mid-IR Supercontinuum Laser

Numerical simulation of the non-linear processes used to generate the output of the SC4500 by propagation of a 2.1 µm, 100 fs, 10 nJ pulse through a dispersion-engineered InF3 fiber.

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Typical power spectral density as a function of wavelength. Please note that this is a sample spectrum and that small variations may occur from unit to unit. The fine structure seen around 2.7 μm is due to water and CO2 absorption in the beam path of the measurement setup. The sharp drop-off at 4.2 μm is also due to CO2 absorption. This spectrum was obtained without purging the laser cavity.
Key Specifications
Wavelength Range 1.3 - 4.5 μm (7700 - 2200 cm-1)
Output Power 300 mW (Minimum)
Mid-IR Output Power 110 mW (Minimum; 2.2 - 4.2 μm)
Output Power
±1% (Room Temperature ±1 °C)
Intensity Noise 0.025% (Typical; RMS; 10 Hz - 1 MHz)
Repetition Rate 50 MHz (Typical)
Beam Output Collimated; Single Spatial Mode
Dimensions 17.92" x 15.89" x 5.84"
(455.2 mm x 403.5 mm x 148.2 mm)


  • 300 mW Output Power Over Entire Bandwidth
  • >110 mW Output Power over 2.2 - 4.2 µm
  • 0.025% (Typical) Intensity Noise Enables Highly Sensitive Measurements
  • Robust All-Fiber Design for Hands-Off, Reliable Operation
  • Record-High Brightness Enables Remote and Standoff Detection
  • Compatible with Standard FTIR Spectrometers
  • Available with Water Cooling for Vibrationally Sensitive Applications (Contact Tech Support)


  • Environmental Sensing
  • Standoff Detection of Chemical and Biological Threats
  • Absorption Spectroscopy with High Sensitivity
  • Infrared Spectromicroscopy
  • Ultrafast Spectroscopy
  • Femtosecond Pulse Generation in the Mid-IR

The SC4500 is the world's first commercially available femtosecond-laser-pumped Mid-IR Supercontinuum Laser Source. This supercontinuum laser emits over a wavelength range from approximately 1.3 μm to 4.5 μm (7700 cm-1 to 2200 cm-1) with >300 mW of average output power in a collimated beam. More than 110 mW of the output power is within the 2.2 - 4.2 µm (4500 cm-1 - 2400 cm-1) range, which overlaps with many gas absorption lines and other molecular signatures. The pulsed femtosecond oscillator driving the supercontinuum runs at a fixed repetition rate of 50 MHz. The brightness of the SC4500 laser exceeds traditional Globars and even synchrotron sources by orders of magnitude.

The laser cavity can be purged via a gas inlet located in the back panel of the laser head. A gas supply connected to this inlet can cause gas to flow through the internal beam path of the laser to reduce undesirable absorption lines in the environment. This gas supply should not be pressurized. The output port of the SC4500 includes a KF16 vacuum compatible flange which can be used to connect the output to other purge capable instruments or devices.

The supercontinuum light is generated by pumping a dispersion-engineered indium fluoride (InF3) fiber with a high-power femtosecond fiber laser. Unlike supercontinuum lasers pumped in the long-pulse regime (picoseconds to nanoseconds), the spectrum of a femtosecond-pumped source is stable from pulse to pulse. As a result, our supercontinuum laser provides a typical output noise of 0.025% (RMS; 10 Hz to 1 MHz), greatly aiding applications that require high-sensitivity detection.

High brightness and low output noise make the SC4500 the ideal laser for sensing and spectroscopy applications in the Mid-IR. Applications range from environmental sensing of greenhouse gases to standoff detection in the field to spectroscopy in the lab using standard FTIR spectrometers. In addition, this laser's shot-to-shot spectral stability allows it to be used as a source of femtosecond pulses in the Mid-IR by filtering the output through a bandpass filter. An all-fiber design with proprietary fluoride-to-silica fiber splices offers robust, reliable, and maintenance-free performance.

We also offer pre-assembled Herriott cells for gas absorption spectroscopy applications.

More details about our mid-IR supercontinuum laser are available from Salem R, Jiang Z, Liu D, et al., Opt. Express 2015 Nov 16; 23 (24): 30592 - 30602.

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Click Here for Raw Data
Typical power spectral density as a function of wavelength. Please note that this is a sample spectrum and that small variations may occur from unit to unit. The fine structure seen around 2.7 μm is due to water and CO2 absorption in the beam path of the measurement setup. The sharp drop-off at 4.2 μm is also due to CO2 absorption. This spectrum was obtained without purging the laser cavity.

Click to Enlarge

A sample measurement of the beam profile was taken at the center of the SC band (~2300 nm) using a bandpass filter with a 500 nm bandwidth. This image represents the result of a Gaussian fit which yields a 1/e2 beam diameter of 5.5 mm and a circularity of 97%.
Item # SC4500
Parameters Min Typical Max
Emission Center Wavelength 1.3 - 4.5 µm (7700 - 2200 cm-1)
Output Power (Full Emission Band) 300 mW - 500 mW
Mid-IR Output Power (2.2 - 4.2 μm)
110 mW - -
Output Power Stability
(Full Emission Band; Room Temperature ±1 °C)
- - ±1%
Intensity Noise (RMS; 10 Hz - 1 MHz) - 0.025% -
Repetition Rate 48 MHz 50 MHz 52 MHz
Output Beam Diameter (1/e2; Single Mode) - 5.5 mm -
Polarization Random
Electrical Requirements
Input Voltage 100 - 240 V
Frequency 50 - 60 Hz
Power Consumption 700 W (Max)
Environmental Requirements
Room Temperature Range 17 °C to 25 °C
Physical Specifications
Gas Purging Inlet Connection 0.25" (6.35 mm) Outer Diameter
Optical Output Connection KF10/KF16 Vacuum Flange
Dimensions (Laser Head) 17.92" x 15.89" x 5.84"
(455.2 mm x 403.5 mm x 148.2 mm)
Dimensions (Controller) 16.97" x 15.68" x 5.24"
(431.0 mm x 398.2 mm x 133.1 mm)

    Laser Warning Label Laser Warning Label


    Version 1.1.513.51

    An installer for the Windows®-based GUI of the SC4500 MIR Supercontinuum Source.

    Software Download

    Laser Safety and Classification

    Safe practices and proper usage of safety equipment should be taken into consideration when operating lasers. The eye is susceptible to injury, even from very low levels of laser light. Thorlabs offers a range of laser safety accessories that can be used to reduce the risk of accidents or injuries. Laser emission in the visible and near infrared spectral ranges has the greatest potential for retinal injury, as the cornea and lens are transparent to those wavelengths, and the lens can focus the laser energy onto the retina. 

    Laser Glasses Laser Curtains Blackout Materials
    Enclosure Systems Laser Viewing Cards Alignment Tools
    Shutter and Controllers Laser Safety Signs

    Safe Practices and Light Safety Accessories

    • Laser safety eyewear must be worn whenever working with Class 3 or 4 lasers.
    • Regardless of laser class, Thorlabs recommends the use of laser safety eyewear whenever working with laser beams with non-negligible powers, since metallic tools such as screwdrivers can accidentally redirect a beam.
    • Laser goggles designed for specific wavelengths should be clearly available near laser setups to protect the wearer from unintentional laser reflections.
    • Goggles are marked with the wavelength range over which protection is afforded and the minimum optical density within that range.
    • Laser Safety Curtains and Laser Safety Fabric shield other parts of the lab from high energy lasers.
    • Blackout Materials can prevent direct or reflected light from leaving the experimental setup area.
    • Thorlabs' Enclosure Systems can be used to contain optical setups to isolate or minimize laser hazards.
    • A fiber-pigtailed laser should always be turned off before connecting it to or disconnecting it from another fiber, especially when the laser is at power levels above 10 mW.
    • All beams should be terminated at the edge of the table, and laboratory doors should be closed whenever a laser is in use.
    • Do not place laser beams at eye level.
    • Carry out experiments on an optical table such that all laser beams travel horizontally.
    • Remove unnecessary reflective items such as reflective jewelry (e.g., rings, watches, etc.) while working near the beam path.
    • Be aware that lenses and other optical devices may reflect a portion of the incident beam from the front or rear surface.
    • Operate a laser at the minimum power necessary for any operation.
    • If possible, reduce the output power of a laser during alignment procedures.
    • Use beam shutters and filters to reduce the beam power.
    • Post appropriate warning signs or labels near laser setups or rooms.
    • Use a laser sign with a lightbox if operating Class 3R or 4 lasers (i.e., lasers requiring the use of a safety interlock).
    • Do not use Laser Viewing Cards in place of a proper Beam Trap.


    Laser Classification

    Lasers are categorized into different classes according to their ability to cause eye and other damage. The International Electrotechnical Commission (IEC) is a global organization that prepares and publishes international standards for all electrical, electronic, and related technologies. The IEC document 60825-1 outlines the safety of laser products. A description of each class of laser is given below:

    Class Description Warning Label
    1 This class of laser is safe under all conditions of normal use, including use with optical instruments for intrabeam viewing. Lasers in this class do not emit radiation at levels that may cause injury during normal operation, and therefore the maximum permissible exposure (MPE) cannot be exceeded. Class 1 lasers can also include enclosed, high-power lasers where exposure to the radiation is not possible without opening or shutting down the laser.  Class 1
    1M Class 1M lasers are safe except when used in conjunction with optical components such as telescopes and microscopes. Lasers belonging to this class emit large-diameter or divergent beams, and the MPE cannot normally be exceeded unless focusing or imaging optics are used to narrow the beam. However, if the beam is refocused, the hazard may be increased and the class may be changed accordingly.  Class 1M
    2 Class 2 lasers, which are limited to 1 mW of visible continuous-wave radiation, are safe because the blink reflex will limit the exposure in the eye to 0.25 seconds. This category only applies to visible radiation (400 - 700 nm).  Class 2
    2M Because of the blink reflex, this class of laser is classified as safe as long as the beam is not viewed through optical instruments. This laser class also applies to larger-diameter or diverging laser beams.  Class 2M
    3R Class 3R lasers produce visible and invisible light that is hazardous under direct and specular-reflection viewing conditions. Eye injuries may occur if you directly view the beam, especially when using optical instruments. Lasers in this class are considered safe as long as they are handled with restricted beam viewing. The MPE can be exceeded with this class of laser; however, this presents a low risk level to injury. Visible, continuous-wave lasers in this class are limited to 5 mW of output power.  Class 3R
    3B Class 3B lasers are hazardous to the eye if exposed directly. Diffuse reflections are usually not harmful, but may be when using higher-power Class 3B lasers. Safe handling of devices in this class includes wearing protective eyewear where direct viewing of the laser beam may occur. Lasers of this class must be equipped with a key switch and a safety interlock; moreover, laser safety signs should be used, such that the laser cannot be used without the safety light turning on. Laser products with power output near the upper range of Class 3B may also cause skin burns.  Class 3B
    4 This class of laser may cause damage to the skin, and also to the eye, even from the viewing of diffuse reflections. These hazards may also apply to indirect or non-specular reflections of the beam, even from apparently matte surfaces. Great care must be taken when handling these lasers. They also represent a fire risk, because they may ignite combustible material. Class 4 lasers must be equipped with a key switch and a safety interlock.  Class 4
    All class 2 lasers (and higher) must display, in addition to the corresponding sign above, this triangular warning sign.  Warning Symbol

    Pulsed Laser Emission: Power and Energy Calculations

    Determining whether emission from a pulsed laser is compatible with a device or application can require referencing parameters that are not supplied by the laser's manufacturer. When this is the case, the necessary parameters can typically be calculated from the available information. Calculating peak pulse power, average power, pulse energy, and related parameters can be necessary to achieve desired outcomes including:

    • Protecting biological samples from harm.
    • Measuring the pulsed laser emission without damaging photodetectors and other sensors.
    • Exciting fluorescence and non-linear effects in materials.

    Pulsed laser radiation parameters are illustrated in Figure 1 and described in the table. For quick reference, a list of equations are provided below. The document available for download provides this information, as well as an introduction to pulsed laser emission, an overview of relationships among the different parameters, and guidance for applying the calculations. 



    Period and repetition rate are reciprocal:    and 
    Pulse energy calculated from average power:       
    Average power calculated from pulse energy:        
    Peak pulse power estimated from pulse energy:            

    Peak power and average power calculated from each other:
    Peak power calculated from average power and duty cycle*:
    *Duty cycle () is the fraction of time during which there is laser pulse emission.
    Pulsed Laser Emission Parameters
    Click to Enlarge

    Figure 1: Parameters used to describe pulsed laser emission are indicated in the plot (above) and described in the table (below). Pulse energy (E) is the shaded area under the pulse curve. Pulse energy is, equivalently, the area of the diagonally hashed region. 

    Parameter Symbol Units Description
    Pulse Energy E Joules [J] A measure of one pulse's total emission, which is the only light emitted by the laser over the entire period. The pulse energy equals the shaded area, which is equivalent to the area covered by diagonal hash marks.
    Period Δt  Seconds [s]  The amount of time between the start of one pulse and the start of the next.
    Average Power Pavg Watts [W] The height on the optical power axis, if the energy emitted by the pulse were uniformly spread over the entire period.
    Instantaneous Power P Watts [W] The optical power at a single, specific point in time.
    Peak Power Ppeak Watts [W] The maximum instantaneous optical power output by the laser.
    Pulse Width Seconds [s] A measure of the time between the beginning and end of the pulse, typically based on the full width half maximum (FWHM) of the pulse shape. Also called pulse duration.
    Repetition Rate frep Hertz [Hz] The frequency with which pulses are emitted. Equal to the reciprocal of the period.

    Example Calculation:

    Is it safe to use a detector with a specified maximum peak optical input power of 75 mW to measure the following pulsed laser emission?

    • Average Power: 1 mW
    • Repetition Rate: 85 MHz
    • Pulse Width: 10 fs

    The energy per pulse:

    seems low, but the peak pulse power is:

    It is not safe to use the detector to measure this pulsed laser emission, since the peak power of the pulses is >5 orders of magnitude higher than the detector's maximum peak optical input power.

    Posted Comments:
    Arindam Banerjee  (posted 2020-03-05 01:23:20.507)
    We are distrobutors of Thorlabs in India. A request from customer for quotation. the application is to characterize Infrared detectors (HgCdTe and InGaAs based). the SC4500 will be used as photon source covering MWIR range. Also this unit will be used for spectral characterization of infrared optical filters as part of an optical test setup
    llamb  (posted 2020-03-05 11:27:28.0)
    Thank you for contacting Thorlabs. A representative will reach out to you directly to discuss your application and provide a quote.
    agoncharov  (posted 2017-10-28 20:50:38.837)
    please provide price and ordering information 202 478 8947 Alex
    tfrisch  (posted 2017-10-30 10:28:59.0)
    Hello, thank you for contacting Thorlabs. We will reach out to you with a quote.

    Based on your currency / country selection, your order will ship from Newton, New Jersey  
    +1 Qty Docs Part Number - Universal Price Available
    SC4500 Support Documentation
    SC4500Mid-IR Supercontinuum Laser, 1.3 to 4.5 μm
    Lead Time