Enhancing High-Speed MIR Detection Using Quantum Cascade Detectors

The electromagnetic spectrum’s mid-infrared (MIR) region is particularly noteworthy due to its vast potential across various applications.

The MIR region boasts rich roto-vibrational spectra of various light molecules, including gases and small organic molecules. MIR absorption spectroscopy is a vital tool for label-free detection in various fields.

MIR wavelengths exhibit low scattering by aerosols, an important characteristic that makes them extremely promising in free-space communication research. Certain regions within the MIR spectrum (around 4 µm and 10 µm) also demonstrate low absorption by atmospheric gases, enabling long-distance free-space communication.

Much of the success of MIR applications stems from the availability of key MIR photonic technologies like quantum cascade detectors (QCDs).

These photovoltaic detectors can function over various spectral regions of the MIR. These advanced instruments can also operate at room temperature without a bias voltage. They also boast low noise, allowing them to confidently compensate for their relatively low photo-response compared to other MIR detectors.

This highly beneficial characteristic pushes QCDs’ specific detectivity above 1 x 10⁹ cm·hz1/2/W. The most interesting feature of QCDs, however, is their extraordinary speed, theoretically exceeding 100 ghz and frequently surpassing 20 ghz at a -3 dB threshold. Hamamatsu Photonics' quantum cascade photodetector (QCD) P16309-01.

Hamamatsu Photonics has recently celebrated a major milestone in MIR technology with the release of the world’s first commercially available QCD.^1,2,3

Hamamatsu Photonics' quantum cascade photodetector (QCD) P16309-01. Image Credit: Hamamatsu Photonics Europe

Image Credit: Hamamatsu Photonics Europe

This pioneering instrument is one of the only commercial QCDs operating at room temperature without an additional cooling mechanism. Its diverse array of potential applications includes high-speed gas detection and high-speed MIR spectroscopy.^4,5

QCDs have the potential to play a central role in kinetic studies of chemical reactions, which typically take place at sub-nanosecond timescales. This capability is key to chemical process development, leading to advances in various fields, from improvements in energy yield to reductions in emissions, as well as driving the widespread adoption of eco-friendly chemicals.

QCDs’ high speeds also pave the way for the development of free-space communication in the MIR region. Their small footprint and straightforward operation make them more popular in large-scale applications such as communication.

Outside of the applications discussed here, many other MIR applications are set to benefit from QCDs’ simplified packaging and impressive performance parameters.

References and Further Reading

1. https://www.hamamatsu.com/jp/en/news/products-and-technolo- gies/2021/20210928000000.html
2. https://www.hamamatsu.com/jp/en/product/optical-sensors/infra- red-detector/qcd/P16309-01.html
3. https://doi.org/10.1063/5.0038147
4. https://doi.org/10.3390/s21175706
5. https://doi.org/10.1038/s42005-020-00420-3

This information has been sourced, reviewed and adapted from materials provided by Hamamatsu Photonics Europe.

For more information on this source, please visit Hamamatsu Photonics Europe.