Infrared spectroscopic imaging is an analytical approach that can reveal important molecular information without the need for substantial sample processing. These instruments can provide objective and automated evaluations to aid pathologists improve diagnostic accuracy. The quantum cascade laser, allows for a discrete frequency approach, increasing imaging speeds with superior spatial and spectral resolution. We present our recent progress toward developing new instruments capable of diffraction limited performance at all fingerprint-region wavelengths across the entire field of view. We demonstrate high throughput imaging of tissue sections and tissue microarrays and evaluate the advantages in data quality obtained from a well-corrected system.
Infrared polarimetry is a powerful label-free diagnostic tool to study the molecular alignment and organization in biological tissues and cells. Similar to absorbance images which capture intensity information, polarimetric imaging is essential for capturing the polarization states of the light intensity. Recent advancements in the development of Quantum Cascade Lasers (QCL) sources have opened new avenues in IR imaging with high spatial and spectral resolution while enabling drastic increases in imaging speeds than a corresponding FT-IR approach. We demonstrate improved performance in terms of fast and comprehensive polarimetric image acquisition using a custom-built QCL microscope with point mapping design.
Infrared spectroscopic imaging has emerged as a powerful label-free diagnostic tool to study the molecular composition and organization in biological tissues and cells. We report infrared spectroscopic imaging using polarized light to study differential absorption of plane-polarized light by an oriented sample to detect valuable information, such as, birefringence and dichroism. For instance, the organization of collagen, specifically fiber orientation and alignment, is crucial in understanding the progression and metastasis of cancer. Recent advancements in the development of Quantum Cascade Lasers (QCL) sources have opened new avenues for high SNR measurements in the field of IR spectroscopy. In addition, QCL sources are intrinsically polarized and orientation information can be obtained at discrete frequencies with different polarization orientations, allowing much faster acquisition than a corresponding FT-IR approach. We demonstrate improved performance in terms of fast and comprehensive polarimetric image acquisition and analysis using custom-built QCL microscope and evaluate its impact on applications by analyzing the important spectral bands of surgical tissue sections.