The Block Engineering miniQCL is a compact, widely tunable mid-infrared quantum cascade laser (QCL) designed for high-speed chemical sensing and spectroscopy. Based on an external-cavity QCL (EC-QCL) architecture, the miniQCL provides broad wavelength tuning from the molecular fingerprint region into the long-wave infrared, offering a flexible laser source for applications where conventional fixed-wavelength QCLs cannot provide sufficient spectral coverage.
Individual miniQCL modules operate across selected ranges between approximately 5.4 and 13 µm, with typical tuning bandwidths greater than 250 cm⁻¹. Multiple modules can be combined to extend coverage across a much wider spectral range. Four modules can provide continuous coverage from approximately 5.4–13 µm, making the platform particularly useful for identifying complex molecules with multiple infrared absorption features.
The miniQCL uses a diffraction grating within the external cavity to tune the QCL emission. This provides rapid wavelength scanning, with reported tuning speeds of approximately 25 cm⁻¹/ms. A single module can therefore scan across more than 250 cm⁻¹ at rates exceeding 100 Hz, enabling high-speed mid-IR spectroscopy and real-time chemical analysis.
Despite its small footprint, the miniQCL provides high peak optical power, operating in pulsed mode with peak powers in the hundreds of milliwatts, pulse durations from 30–500 ns and pulse repetition frequencies up to 3 MHz. Most configurations can operate with a duty factor of at least 10% using air cooling. The compact module measures approximately 43 × 23 × 17 mm, excluding electrical leads.
With a typical laser linewidth below 2 cm⁻¹, near-diffraction-limited beam quality and excellent pointing stability, the miniQCL is well suited to gas sensing, chemical identification, process monitoring, pharmaceutical analysis, environmental monitoring and standoff detection. Its combination of wide tuning, rapid scanning and compact size also makes it attractive for OEM instrument development and portable mid-IR spectroscopy systems.
