Clicking this icon opens a window that contains specifications and mechanical drawings.
Clicking this icon allows you to download our standard support documentation.
Choose Item
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.
Features
Single-Wavelength Distributed Feedback Quantum or Interband Cascade Lasers (DFB QCLs and ICLs)
High Heat Load Package Simplifies Thermal Management and System Integration
Collimated Laser Emission Through Wedged Window
Used in Chemical Analysis, Sensing, and IR Countermeasures
Custom Packages and Wavelengths from 3 to 12 µm Available via Tech Support
The MIR quantum and interband cascade lasers on this webpage are offered in high heat load (HHL) packages with industry-standard pinouts and package dimensions. Each package incorporates a built-in thermistor and thermoelectric cooler (TEC) for active temperature management and prolonged laser lifetime, and also includes an internal aspheric lens that collimates the laser's output.
Distributed feedback QCLs and ICLs emit at a well defined center wavelength, making them popular for applications such as chemical sensing and sample analysis. They provide single spatial mode operation. By tuning the input current and operating temperature, the laser output can be tuned over a narrow range of at least 1 cm-1. 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.
Our ICLs emit a horizontally polarized beam at wavelengths as long as 3.5 µm, while our QCLs emit a vertically polarized beam at wavelengths as long as 11µm. ICLs will also typically have lower voltage requirements and threshold currents, thus leading to lower optical output powers. Conversely, QCLs will consume more power and will therefore have higher output powers.
Package Details As measured from the bottom of the package, the emission height is 12.7 ± 0.13 mm. The output beam is collimated by an AR-coated black diamond aspheric lens and then coupled out of the package through a wedged zinc sulfide (ZnS) window. This wedge prevents back reflections from returning to the laser chip, but also causes the output beam to deviate downward from the normal by -2.0° ± 1.5°, as shown in the Drawing tab of the blue info icons ( ) below. Our stocked lasers are sealed, although the seal is not hermetic; hermetically sealed versions are available by contacting Tech Support.
Each laser is electrically isolated from its mount. Heat loads for these lasers can be up to 38 W, so they must be mounted on a thermally conductive surface to prevent heat buildup. 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. The Handling tab contains more tips and information. These QCLs and ICLs are specified for CW output. While pulsed output is possible, this application prohibits current tuning, and performance is not guaranteed. These lasers do not have built-in monitor photodiodes and therefore cannot be operated in constant power mode.
For OEM applications, Thorlabs also offers QCLs on a compact D-mount package (12.0 mm × 4.5 mm × 2.8 mm).
Thorlabs manufactures custom and OEM quantum cascade lasers in high volumes. We maintain a broad chip inventory at our Jessup, Maryland laser manufacturing facility (see the graph to the left), and can deliver DFB lasers with custom center wavelengths that are qualified to a user-defined wavelength precision.
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 our MIR lasers. The first table lists the controllers with which a particular MIR 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. We particularly recommend our ITC4002QCL and ITC4005QCL controllers, which have high compliance voltages of 17 V and 20 V, respectively. Together, these drivers support the current and voltage requirements of our entire line of Mid-IR Lasers. 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.
Please note that Thorlabs does not offer cables that connect high heat load lasers to our controllers, and that third-party cables for these packages are typically not rated for the 4.5 A maximum current of the internal thermoelectric cooler. 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
Do Not
Expose the Laser to Smoke, Dust, Oils, Adhesive Films, or Flux Fumes
Blow on the Laser
Drop the Laser Package
Handling High Heat Load Lasers
Proper precautions must be taken when handling and using high heat load 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 Contamination of the window must be avoided. Do not blow on the window or expose it to smoke, dust, oils, or adhesive films. The window is particularly sensitive to dust accumulation. During standard operation, dust can burn onto it, which will lead to premature degradation of the laser performance. If operating a high heat load laser for long periods of time outside a cleanroom, it should be sealed in a container to prevent dust accumulation.
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. 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 high heat load DFB QCLs and ICLs, this value is 38 W.
The bottom face of the high heat load package is machined flat to make proper thermal contact with a heat sink. Ideally, the heat sink will be actively temperature regulated to ensure proper heat conduction. A fan may serve to move the heat away from the package and prevent thermal runaway. However, the fan should not blow air on or at the laser itself. Thermal grease, pyrolytic graphite, and water cooling methods may also be employed for temperature regulation.
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.
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.
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.
The graphs below and photos to the right illustrate some of our custom capabilities. Please visit our semiconductor manufacturing capabilities presentation to learn more.
Click to Enlarge Maximum Output Power of Custom Fabry-Perot QCLs
Click to Enlarge Electroluminescence Spectra of Available Gain Chip Material
Insights into QCLs and ICLs
Scroll down to read about:
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
Posted Comments:
user
 (posted 2020-07-28 07:57:43.757)
Hello,
I would like to know if I can push the power output of the laser diode to higher values then the ones given here. The way that I understood the limitations of the diode is as follows: When applying a DC current to the diode there is a threshold such that increasing the current intensity will not result in higher output powers, but rather just heat up the laser diode. So I was wondering if I could circumvent the heat build-up inside the diode by only using the laser diode to shot pulses of the order of 100 micros. My hope is that during those short pulses higher power output values will be reached without overheating the lasing material.
I was wondering if this strategy is legit or if it will most likely damage the laser diode. I am happy about any thoughts or comments. Thanks in advance.
YLohia
 (posted 2020-07-30 03:11:27.0)
Hello, thank you for contacting Thorlabs. It is indeed possible to get high powers out of these, either with pulsed operation or with adequate cooling. I have reached out to you directly to discuss this further.
The rows shaded green below denote single-frequency lasers.
These lasers emit at a well defined wavelength that can be tuned over a narrow range. Each device has different optical characteristics. To get the spectrum and output power of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs icon next to the serial number. If you need a wavelength that is not listed below, please request it by contacting Tech Support.
Do not exceed the maximum optical power or maximum drive current, whichever occurs first.
Please note that the absolute maximum current is determined on a device-by-device basis. It is listed on the device's data sheet. To view, click "Choose Item" below, then click on the Docs icon next to the serial number.
These lasers emit at a well defined wavelength that can be tuned over a narrow range. Each device has different optical characteristics. To get the spectrum and output power of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs icon next to the serial number. If you need a wavelength that is not listed below, please request it by contacting Tech Support.
Do not exceed the maximum optical power or maximum drive current, whichever occurs first.
Please note that the absolute maximum current is determined on a device-by-device basis. It is listed on the device's data sheet. To view, click "Choose Item" below, then click on the Docs icon next to the serial number.
These lasers emit at a well defined wavelength that can be tuned over a narrow range. Each device has different optical characteristics. To get the spectrum and output power of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs icon next to the serial number. If you need a wavelength that is not listed below, please request it by contacting Tech Support.
Do not exceed the maximum optical power or maximum drive current, whichever occurs first.
Please note that the absolute maximum current is determined on a device-by-device basis. It is listed on the device's data sheet. To view, click "Choose Item" below, then click on the Docs icon next to the serial number.
These lasers emit at a well defined wavelength that can be tuned over a narrow range. Each device has different optical characteristics. To get the spectrum and output power of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs icon next to the serial number. If you need a wavelength that is not listed below, please request it by contacting Tech Support.
Do not exceed the maximum optical power or maximum drive current, whichever occurs first.
Please note that the absolute maximum current is determined on a device-by-device basis. It is listed on the device's data sheet. To view, click "Choose Item" below, then click on the Docs icon next to the serial number.
These lasers emit at a well defined wavelength that can be tuned over a narrow range. Each device has different optical characteristics. To get the spectrum and output power of a specific, serial-numbered device, click "Choose Item" below, then click on the Docs icon next to the serial number. If you need a wavelength that is not listed below, please request it by contacting Tech Support.
Do not exceed the maximum optical power or maximum drive current, whichever occurs first.
Please note that the absolute maximum current is determined on a device-by-device basis. It is listed on the device's data sheet. To view, click "Choose Item" below, then click on the Docs icon next to the serial number.