Our understanding of the world relies greatly on our knowledge of its constituent materials and their interactions. Recent advances in materials science technologies have ratcheted up our ability to discover chemical substances and expanded possible applications.
One such technology is infrared spectroscopy, used for molecular identification in various fields, similar to in medicine, environmental monitoring, and industrial production. Nonetheless, even the perfect existing tool — the Fourier transform infrared spectrometer or FTIR — utilizes a heating element as its light source. Resulting detector noise within the infrared region limits the devices’ sensitivity, while physical properties hinder miniaturization.
Now, a research team led by Kyoto University has addressed this problem by incorporating a quantum light source. Their progressive ultra-broadband, quantum-entangled source generates a comparatively wider range of infrared photons with wavelengths between 2 μm and 5 μm.
“This achievement sets the stage for dramatically downsizing the system and upgrading infrared spectrometer sensitivity,” says Shigeki Takeuchi of the Department of Electronic Science and Engineering.
One other elephant within the room with FTIRs is the burden of transporting mammoth-sized, power-hungry equipment to numerous locations for testing materials on-site. Takeuchi eyes a future where his team’s compact, high-performance, battery-operated scanners will result in easy-to-use applications in various fields similar to environmental monitoring, medicine, and security.
“We are able to obtain spectra for various goal samples, including hard solids, plastics, and organic solutions. Shimadzu Corporation — our partner that developed the quantum light device — has concurred that the broadband measurement spectra were very convincing for distinguishing substances for a wide selection of samples,” adds Takeuchi.
Although quantum entangled light just isn’t latest, bandwidth has so far been limited to a narrow range of 1 μm or less within the infrared region. This latest technique, meanwhile, uses the unique properties of quantum mechanics — similar to superposition and entanglement — to beat the constraints of conventional techniques.
The team’s independently developed chirped quasi-phase-matching device generates quantum-entangled light by harnessing chirping — progressively changing a component’s polarization reversal period — to generate quantum photon pairs over a large bandwidth.
“Improving the sensitivity of quantum infrared spectroscopy and developing quantum imaging within the infrared region are a part of our quest to develop real-world quantum technologies,” remarks Takeuchi.
