Article Highlights
- Conventional IR spectroscopy faces limitations such as bulky equipment, limited bandwidth, and sensitivity issues, prompting the exploration of quantum IR spectroscopy as an alternative method.
- Researchers from Kyoto University developed ultra-broadband quantum entangled states of visible and IR photons, enabling unprecedented broadband measurements using a specially designed nonlinear crystal.
- The experimental demonstration of quantum IR spectroscopy exhibited great accuracy in measuring IR spectra across various samples, showing potential for applications in quantum imaging.
Infrared (IR) spectroscopy is a spectroscopic technique that measures interactions of IR radiation with matter by absorption, emission, or reflection. IR spectroscopy is normally used to identify chemical substances and functional groups in all phases of matter (1).
Although it is a mature and well-understood analytical method used for analysis of organic and inorganic molecules, IR spectroscopy does have limitations as a technique. Conventional IR spectroscopy encounters challenges such as bulky equipment, limited bandwidth, and sensitivity issues from blackbody radiation (2). In this study from Optica, researchers from Kyoto University explored using quantum IR spectroscopy as an alternative method to traditional IR spectroscopy (2).
In their study, the research team generated ultra-broadband entangled states of visible and IR photons spanning wavelengths from 2–5 micrometers (2). This feat was achieved through the utilization of a specially designed nonlinear crystal with a chirped poling structure, enabling unprecedented broadband measurements crucial for various spectroscopic applications (2).
Using the ultra-broadband quantum entangled photons, the research team made a nonlinear quantum interferometer. Doing so allowed the team to realize broadband IR spectroscopy using a silicon visible detector (2).
