Researchers have developed a unique high-resolution imaging method that can capture mid-infrared spectral images of fast events or dynamic processes that take place on the order of milliseconds. This spectral range is used for many applications because it can reveal the detailed chemical composition of a sample.
This novel approach could one day be used to prescreen medical biopsies to identify the ones that need closer examination. It could be used to look for the chemical signatures of cancer and other diseases in ways that would increase the accuracy and speed of diagnoses.
The researchers drew on a process known as nonlinear frequency conversion in which energy is added to a photon to change its wavelength, and hence it’s color. Although frequency conversion, or upconversion, is often used to change the wavelength of a laser’s output, the researchers developed a detection system that could shift an entire mid-IR image into the near-infrared wavelength range while preserving all the spatial information.
The fast events imaging system incorporates a new mid-infrared light source. This single-wavelength light source can be tuned to different wavelengths and it also uses frequency conversion to generate the mid-infrared light. In fact, the researchers used the same pulsed near-infrared laser for two things: to generate the tunable mid-IR light and to achieve the image upconversion.