Quantum Cascade Lasers – QCLs, QCL Lasers

Quantum Cascade Lasers - mirSense Product Family

What is a Quantum Cascade Laser or QCL?

Quantum cascade lasers (QCLs) are intersubband semiconductor lasers emitting around a center wavelength ranging from the mid-wave infrared (MWIR) to the long-wave infrared (LWIR) spectral regions.

While, technically, QCLs are a subset of semiconductor lasers, in practice, they are fundamentally different enough to warrant their unique classification. Conventional semiconductor lasers utilize bulk semiconductor crystal with typical interband transitions – the recombination of electron-hole pairs across the material bandgap – emitting a single photon.

QCLs use a periodic series of thin active sections of various material compositions and thicknesses in the form of a superlattice. This superlattice is a series of stepwise electric potentials across the device, with a sloping potential gradient, which in turn results in the electron having to ‘cascade’ down through the potential wells. This process produces higher optical gain, emitting multiple photons per electron, one photon at each step or well. Since the energy level positions are determined primarily by layer thickness, the emission wavelength of QCLs can be tuned to match a customer’s specific wavelength requirement.

As a result, the wavelength is not limited by the intrinsic energy gap of the material and can produce wavelengths in the mid-IR range. Furthermore, the cascade effect creates an enhancement factor that allows for QCLs to provide several orders of magnitude more power at a given wavelength than traditional semiconductor lasers.

Figure 1: Comparison of the bandgap conventional diode structure lasers (left) and QCLs (left). Courtesy of mirSense based in Palaiseau, France.

Our Quantum Cascade Laser Products

The QCLs designed and manufactured by mirSense are high-powered diodes (typically watt-level). The PowerMir line emits in the main transmission bands of the atmosphere (4.0µm, 4.6µm, 4.8µm, 9.x µm). Furthermore, the new line of  UniMir Distributed Feedback (DFB) QCLs emit in the LWIR spectral region (11.3, 13.4, 14, 14.9 & 16µm). The PowerMir line are Fabry-Perot laser sources operating in the quasi CW regime. In other words, pulsed operation down to few tens of nanoseconds and high frequency above MHz at room temperature. The UniMir line are DFB sources with CW operation. These products exhibit high average power and wall-plug efficiency. Therefore, perfect for counter-measure and other defense applications, as well as gas detection in the nuclear and petrochemical industries.

MirSense offers a full range of ITAR-free products from chip on submount manufacturing to full turnkey systems. For example, for OEM system integrators, mirSense manufactures a packaged diode plugged in to a top-notch PCB driver that includes laser control, thermal management and security and safety. To clarify, this packaged diode is the “POEM” system (POEM stands for PowerMir OEM system).

The QCLs from mirSense are proudly manufactured in first-class clean rooms in the heart of the French optics valley on the “Saclay Plateau” near Paris. MirSense focuses on serving industrial customers that require a high level of laser repeatability to ensure good batch-to-batch quality for series-productions. Furthermore, customers will find that mirSense offers a very high beam quality.

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PowerMir Series

mirSense Product Family

The PowerMir series is a high-power pulsed Quantum Cascade Laser based on proprietary technology which incorporates high-powered diodes (typically watt-level) emitting in the main transmission bands of the atmosphere (4.0µm, 4.6µm, 4.8µm, 9.x µm). The ITAR free MirSense technology exhibits outstanding performance in terms of power and wall-plug efficiency. This high-performance QCL laser assembly takes full advantage of MirSense’s state of the art technologies.

UniMir Series

mirSense UniMir HHLThe PowerMir Series is a long-wavelength, single-frequency, DFB, CW Quantum Cascade Laser based on proprietary technology. The technology’s versatility allows them to address any wavelength between 10 and 18µm in CW and up to 21µm in pulsed mode. now commercially available in a sealed High Heat Load (HHL) package, with integrated collimating lens, thermistor, and thermoelectric cooler (TEC), well suited for integration into systems, or as a stand-alone turnkey system for R&D and detection applications.