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IR Quantum Cascade Lasers (QCL)

QCLs are tunable infrared light sources. Our QCLs are from our partners, Alpes Lasers SA in Switzerland. QCL technology and production has rapidly matured, and they are being applied in a wide range of applications including:

  • Security
  • Defense
  • Environmental Monitoring
  • Gas Sensing
  • Life Sciences
  • Scientific Instrumentation

Why QCLs? Because most chemical compounds have their fundamental vibrational modes in the mid-infrared, spanning approximately the wavelength region from 3 to 15μm, this part of the electromagnetic spectrum is very important for gas sensing and spectroscopy applications. Even more important are the two atmospheric windows at 3-5μm and 8-12μm. The transparency of the atmosphere in these two windows allows remote sensing and detection.

New devices are continually available, either expanded wave nember or new device designs and applications.  Of note:

  1. Frequency Comb Quantum Cascade Lasers emitting light on a wide spectrum consisting of equidistant peaks in frequency space (info).
  2. device are also now available in Terahertz frequencies (1 – 5 THz).  Call for additional information.
  3. SWIR laser diodes (1.5 – 2.2 um) up to 50 mW output (info)

Select the QCL Products category below for further information.

QCL are ‘naturally’ multi-wavelength Fabry-Perot (FP-QCL) devices unless some mechanism is applied to have the laser emit at a single frequency/wavelength.

There are two principle ways to achieve single wavelength operation. The first is to ‘write’ a grating on the device itself so that the device emits at a specific wavelength set by the grating frequency. Tuning is then accomplished over a very narrow frequency/wavelength region by varying the device temperature which in turn varies the index of refraction of the device material and thus varies the optical path length with respect to the grating and thus varies the emitted wavelength. This method typically allows tuning over 4 to 10 cm-1. These gratings are referred to as “distributed feedback” mechanisms or DFBs, and a QCL that has such a grating is a DFB-QCL.

The typical spectral range of these single mode devices is 700 to 24000 wavenumbers (cm-1) or14 down to 4 microns in wavelength.

The second tuning method is to insert the multi-wavelength Fabry-Perot device into an external cavity which can itself be tuned to promote emission over a spectral region of 10s or even 100s of cm-1. That is, instantaneous linewidth can be << 1 cm-1 and the line can be tuned over the wider region. These are called “EC-QCLs”.

For larger tuning ranges we also supply or an External Cavity Laser Kit (ECLK) or you can buy external cavity devices from Block Engineering, Daylight Solutions or Pranalytica.

Frequency Comb QCL are also available. These devices emit light on a wide spectrum consisting of equidistant peaks in frequency space.

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