|Location:||Rebecca's Cafe, 275 Grove St., Auburndale, MA 02466|
|Dinner Reservation Deadline:||March 13, 2017 @ 6pm|
Mid-infrared photothermal imaging in the fingerprint region
Mid-infrared spectral imaging in the fingerprint region (at wavelengths ~5µm and longer) can reveal characteristic details about molecular compounds and secondary structure of chemicals and biomolecules. In this talk, the development of a contact-less, non-destructive mid-infrared imaging system with high sensitivity and specificity based on photothermal spectroscopy will be presented. First, the development of low-noise, near-infrared fiber lasers will be discussed. Next, the photothermal system that integrates a compact fiber laser with a tunable mid-infrared quantum cascade laser as a robust table-top measurement system will be introduced. The imaging contrast relies on absorption of the mid-infrared pump laser from vibrational normal modes which induces thermal changes in the refractive index that are measured with the probe laser. With scaling of the pump power a nonlinear photothermal spectroscopy regime promises a novel multi-dimensional characterization method for materials with enhanced sensitivity with improved spatial resolution. Applications of the presented system can range from chemical trace to hazardous material detection, and from identification of neurodegenerative diseases based on secondary protein configurations, to remote sensing and process control.