Optically Super-resolved InfraRed Imaging micro-Spectroscopy

Broadband spectroscopy is antithetical to microscopy. This concept, articulated in the diffraction limits of Abbe and Rayleigh, has traditionally stood as the fundamental limiting factor of the imaging disciplines. For spectroscopy, this implies that the spatial resolution of a hyperspectral image is limited by the longest wavelength of the spectrum. While broadband spectroscopy has established itself as perhaps the most useful technique for chemical identification and analysis, the superior resolution of optical microscopy has allowed it to persist as the canonical technique in Biology and an invaluable tool in Materials Science, despite most interesting chemical information lying in the longer wavelength – lower resolution – infrared region of the spectrum. Here we present a novel technique to break the correspondence between wavelength and spatial resolution. Optically Super-resolved InfraRed Imaging micro-Spectroscopy (OSIRIS) permits the collection of fully broadband hyperspectral images at the maximum optical spatial resolution. Modulated long wavelength light is directed onto the sample, while a short wavelength probe beam senses the resultant modulation in local temperature. A spectrum is collected by varying the wavelength of the modulated light. Thus, OSIRIS constitutes the full generalization of color vision to full spectral bandwidth with spatial resolutions up to the maximum achievable with super-resolution and coherent microscopy (λprobe/4NA ≥ 70 nm). The non-contact nature of OSIRIS permits deep tomography and real-time imaging via multiplexing of the probe beam, while preserving the versatility and ease of use of optical microscopy. The impact of a mature OSIRIS microscope combining the versatility, speed, and spatial resolution of optical microscopy with the analytical power and chemical specificity of infrared spectroscopy cannot be understated.