Clicking this icon opens a window that contains specifications and mechanical drawings.
Clicking this icon allows you to download our standard support documentation.
Clicking the words "Choose Item" opens a drop-down list containing all of the in-stock lasers around the desired center wavelength. The red icon next to the serial number then allows you to download L-I-V and spectral measurements for that serial-numbered device.
3.85 µm, 4.05 µm, or 4.60 µm Center Wavelengths (2597 cm-1, 2469 cm-1, or 2174 cm-1 Wavenumbers)
Custom Wavelengths and Packages Also Available (Contact Tech Support for Details)
Thorlabs' TO-can-packaged Fabry-Perot Quantum Cascade Lasers provide the power and broadband mid-IR emission of a Fabry-Perot QCL in a convenient Ø9 mm TO can package. The broadband emission of each laser makes them well suited for medical imaging, illumination, and thermal signal simulation. The Ø9 mm TO can package incorporates an additional copper disk for added heat dissipation. The additional material makes this TO can thicker than standard Ø9 mm packages, but the lasers are still compatible with all Ø9 mm laser mounts. An AR-coated ZnSe window protects the device from dust and debris.
The output power of each Fabry-Perot QCL is the sum over the full spectral bandwidth. Before shipment, the output spectrum, optical power, and L-I-V curve are measured for each serial-numbered device by an automated test station. These measurements are available below and are also included on a data sheet with the laser. After clicking "Choose Item" below, a list will appear that contains the dominant wavelength, output power, and operating current of each in-stock unit. Clicking on the red Docs Icon next to the serial number provides access to a PDF with serial-number-specific L-I-V and spectral characteristics.
While each QCL is specified for CW output, pulsed output is possible. These lasers do not have a built-in monitor photodiode and therefore cannot be operated in constant power mode.
Mounts, Drivers, and Temperature Control The LDM90 Laser Mount along with the ITC4002QCL or ITC4005QCL Dual Current / Temperature Controller includes all the necessary components to mount, drive, and thermally regulate these lasers up to the 8 W cooling capacity of the LDM90. When run at full power, some QCLs may exceed the cooling capacity of the LDM90. Therefore, care must be taken that the product of the operating current and forward voltage does not exceed 8 W. The individual spec sheet of each quantum cascade laser will list typical values for operating current and forward voltage.
If designing your own mounting solution, note that due to these lasers' heat loads, we recommend that they be mounted in a thermally conductive housing to prevent heat buildup. Heat loads for Fabry-Perot QCLs can be up to 18 W (see the Handling tab for additional information).
Thorlabs manufactures custom and OEM quantum cascade lasers in high volumes. We maintain chip inventory from 3 µm to 12 µm at our Jessup, Maryland, laser manufacturing facility and can reach multi-watt output on certain custom orders.
More details are available on the Custom & OEM Lasers tab. To inquire about pricing and availability, please contact us. A semiconductor specialist will contact you within 24 hours or the next business day.
Current and Temperature Controllers
Use the tables below to select a compatible controller for for our MIR lasers. The first table lists the controllers with which the laser is compatible, and the second table contains selected information on each controller. Complete information on each controller is available in its full web presentation.
To get L-I-V and spectral measurements of a specific, serial-numbered device, click "Choose Item" next to the part number below, then click on the Docs Icon next to the serial number of the device.
Laser Mount Compatibility Thorlabs' LDM90 Laser Mount is fully compatible with the ITC4002QCL and ITC4005QCL controllers; however, the mount itself has a limited heat load of 8 W, meaning some QCLs cannot be driven at full power in this mount. If designing your own mounting solution, note that due to these lasers' heat loads, we recommend that they be secured in a thermally conductive housing to prevent heat buildup. Heat loads for QCLs can be up to 12 W.
Thorlabs does not currently offer cables that connect the LDMC20 mount to this controller. Custom cables will be required.
Provide External Temperature Regulation (e.g., Heat Sinks, Fans, and/or Water Cooling)
Use a Constant Current Source Specifically Designed for Lasers
Observe Static Avoidance Practices
Be Careful When Making Electrical Connections
Use Thermal Grease with C-Mount or D-Mount Lasers
Expose the Laser to Smoke, Dust, Oils, Adhesive Films, or Flux Fumes
Blow on the Laser
Drop the Laser Package
Use Solder with TO Can or D-Mount Lasers
Handling TO Can, Two-Tab C-Mount, D-Mount, and High Heat Load Lasers
Proper precautions must be taken when handling and using TO Can, two-tab C-mount, D-mount, or high heat load (HHL) lasers. Otherwise, permanent damage to the device will occur. Members of our Technical Support staff are available to discuss possible operation issues.
Avoid Static Since these lasers are sensitive to electrostatic shock, they should always be handled using standard static avoidance practices.
Avoid Dust and Other Particulates Unlike TO can and butterfly packages, the laser chip of a C-mount or D-mount laser is exposed to air; hence, there is no protection for the delicate laser chip. Contamination of the laser facets must be avoided. Do not blow on the laser or expose it to smoke, dust, oils, or adhesive films. The laser facet is particularly sensitive to dust accumulation. During standard operation, dust can burn onto this facet, which will lead to premature degradation of the laser. If operating a C-mount or D-mount laser for long periods of time outside a cleanroom, it should be sealed in a container to prevent dust accumulation.
HHL lasers and TO cans are sealed (although the seal is not hermetic), so the laser chip will not be exposed to air. However, similar dust avoidance precautions should be followed for the window on these packages, since the windows are exposed to the atmosphere.
Use a Current Source Specifically Designed for Lasers These lasers should always be used with a high-quality constant current driver specifically designed for use with lasers, such as any current controller listed in the Drivers tab. Lab-grade power supplies will not provide the low current noise required for stable operation, nor will they prevent current spikes that result in immediate and permanent damage.
Thermally Regulate the Laser Temperature regulation is required to operate the laser for any amount of time. The temperature regulation apparatus should be rated to dissipate the maximum heat load that can be drawn by the laser. For our two-tab C-mount or TO can quantum cascade lasers, this value can be up to 18 W. The LDMC20 C-Mount Laser Mount, which is compatible with our two-tab C-mount package, is rated for >20 W of heat dissipation. The LDM90 Ø9 mm TO Can Laser Mount is only rated for 8 W of heat dissipation, so some quantum cascade lasers cannot be operated at full power. Our DFB D-mount laser's maximum heat load is 7.2 W, our FP D-mount lasers' maximum heat load is 25 W, and our HHL QCLs have a maximum heat load of 38 W.
The back face of the C-mount package and the bottom face of the D-mount or high heat load package is machined flat to make proper thermal contact with a heat sink. Ideally, the heat sink will be actively regulated to ensure proper heat conduction. A Thermoelectric Cooler (TEC) is well suited for this task and can easily be incorporated into any standard PID controller. The HHL package incorporates a suitable TEC.
A fan may serve to move the heat away from the TEC and prevent thermal runaway. However, the fan should not blow air on or at the laser itself. Water cooling methods may also be employed for temperature regulation. Although thermal grease is acceptable for TO can and HHL lasers, it should not be used with two-tab C-mount or D-mount lasers, since it can creep, eventually contaminating the laser facet. Pyrolytic graphite is an acceptable alternative to thermal grease for these cases. Solder can also be used to thermally regulate two-tab C-mount lasers, although controlling the thermal resistance at the interface is important for best results. Solder is not recommended for thermal regulation of D-mount or HHL lasers.
For assistance in picking a suitable temperature controller for your application, please contact Tech Support.
Carefully Make Electrical Connections When making electrical connections, care must be taken. The flux fumes created by soldering can cause laser damage, so care must be taken to avoid this.
Solder can be avoided entirely for two-tab C-mount and TO can lasers by using the LDMC20 or LDM90 laser mounts, respectively. If soldering to the tabs on a two-tab C-mount, solder with the C-mount already attached to a heat sink to avoid unnecessary heating of the laser chip. We do not recommend soldering lasers in TO can packages.
Although soldering to the leads of our HHL lasers is possible, we generally recommend using cables specifically designed for HHL packages. Please note that third-party cables for high heat load packages are typically not rated for the 4.5 A maximum current of the internal thermoelectric cooler. If soldering to the leads on an HHL package, the maximum soldering temperature and time are 250 °C and 10 seconds, respectively.
For D-mount lasers, solder should never be used; wire bonding or probe connections are the only recommended methods.
Minimize Physical Handling As any interaction with the package carries the risk of contamination and damage, any movement of the laser should be planned in advance and carefully carried out. It is important to avoid mechanical shocks. Dropping the laser package from any height can cause the unit to permanently fail.
Custom & OEM Quantum Cascade and Interband Cascade Lasers
At our semiconductor manufacturing facility in Jessup, Maryland, we build a wide range of mid-IR lasers and gain chips. Our engineering team performs in-house epitaxial growth, wafer fabrication, and laser packaging. We maintain chip inventory from 3 µm to 12 µm, and our vertically integrated facilities are well equipped to fulfill unique requests.
High-Power Fabry-Perot QCLs For Fabry-Perot lasers, we can reach multi-watt output power on certain custom orders. The available power depends upon several factors, including the wavelength and the desired package.
DFB QCLs at Custom Wavelengths For distributed feedback (DFB) lasers, we can deliver a wide range of center wavelengths with user-defined wavelength precision. Our semiconductor specialists will take your application requirements into account when discussing the options with you.
QCLs and ICLs: Operating Limits and Thermal Rollover
Click here for more insights into lab practices and equipment.
QCLs and ICLs: Operating Limits and Thermal Rollover
Click to Enlarge Figure 2: This set of L-I curves for a QCL laser illustrates that the mount temperature can affect the peak operating temperature, but that using a temperature controlled mount does not remove the danger of applying a driving current large enough to exceed the rollover point and risk damaging the laser.
Click to Enlarge Figure 1: This example of an L-I curve for a QCL laser illustrates the typical non-linear slope and rollover region exhibited by QCL and ICL lasers. Operating parameters determine the heat load carried by the lasing region, which influences the peak output power. This laser was installed in a temperature controlled mount set to 25 °C.
The light vs. driving current (L-I) curves measured for quantum and interband cascade Lasers (QCLs and ICLs) include a rollover region, which is enclosed by the red box in Figure 1.
The rollover region includes the peak output power of the laser, which corresponds to a driving current of just under 500 mA in this example. Applying higher drive currents risks damaging the laser.
Laser Operation These lasers operate by forcing electrons down a controlled series of energy steps, which are created by the laser's semiconductor layer structure and an applied bias voltage. The driving current supplies the electrons.
An electron must give up some of its energy to drop down to a lower energy level. When an electron descends one of the laser's energy steps, the electron loses energy in the form of a photon. But, the electron can also lose energy by giving it to the semiconductor material as heat, instead of emitting a photon.
Heat Build Up Lasers are not 100% efficient in forcing electrons to surrender their energy in the form of photons. The electrons that lose their energy as heat cause the temperature of the lasing region to increase.
Conversely, heat in the lasing region can be absorbed by electrons. This boost in energy can scatter electrons away from the path leading down the laser's energy steps. Later, scattered electrons typically lose energy as heat, instead of as photons.
As the temperature of the lasing region increases, more electrons are scattered, and a smaller fraction of them produce light instead of heat. Rising temperatures can also result in changes to the laser's energy levels that make it harder for electrons to emit photons. These processes work together to increase the temperature of the lasing region and to decrease the efficiency with which the laser converts current to laser light.
Operating Limits are Determined by the Heat Load Ideally, the slope of the L-I curve would be linear above the threshold current, which is around 270 mA in Figure 1. Instead, the slope decreases as the driving current increases, which is due to the effects from the rising temperature of the lasing region. Rollover occurs when the laser is no longer effective in converting additional current to laser light. Instead, the extra driving creates only heat. When the current is high enough, the strong localized heating of the laser region will cause the laser to fail.
A temperature controlled mount is typically necessary to help manage the temperature of the lasing region. But, since the thermal conductivity of the semiconductor material is not high, heat can still build up in the lasing region. As illustrated in Figure 2, the mount temperature affects the peak optical output power but does not prevent rollover.
The maximum drive current and the maximum optical output power of QCLs and ICLs depend on the operating conditions, since these determine the heat load of the lasing region.
Date of Last Edit: Dec. 4, 2019
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The rows shaded green below denote single-frequency lasers.
The rows shaded green above denote single-frequency lasers.
3.85 µm - 4.60 µm TO Can Fabry-Perot QCLs
Max Operating Currentb
3.85 µm (2597 cm-1)
4.05 µm (2469 cm-1)
4.60 µm (2174 cm-1)
4.60 µm (2174 cm-1)
Fabry-Perot Lasers exhibit broadband emission. The center wavelength is defined as a weighted average over all the modes. Each device has a unique spectrum. To get the spectrum of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs Icon next to the serial number of the device. If you need spectral characteristics different than those shown below, please contact Tech Support to request a custom laser.
Please see the the blue info icons () above for absolute maximum power and current specifications. Do not exceed these values, whichever occurs first.
The Ø9 mm package for these diodes is 4.30 mm (0.17") thick, which is more than the standard 1.50 mm (0.06"). The laser will still be compatible with all Ø9 mm laser mounts; please see the Drawing tab in the blue info icon () above for full package specifications.