title: Laser-based mid-infrared reflectance imaging of biological tissues.
abstract: Mid-infrared (MIR) (3-12 um) spectral imaging is a power analytical tool, but difficult in the back-reflectance mode for in-vivo diagnostics. Feasibility of MIR back-reflectance imaging is demonstrated using MIR semiconductor lasers. Transmittance through 500-microm thick films of water and blood showed a capability to resolve more than 6-OD signal dynamic range. Reflectance scanning imaging through a 150-microm thick film of blood showed negligible scattering effect, indicating the feasibility of optical coherent imaging. The result of coherent imaging of a plant leaf shows a MIR sub-surface image that would not be visible in white light. With two wavelengths, a similar result for a chicken skin subcutaneous tissue at different focal depths was obtained, showing blood vessels beneath a lipid layer. These results suggest that advanced multilaser wavelength systems in the fingerprint spectral region can be a useful tool for in-vivo spectral imaging in biomedical research and diagnostic applications.
authors.forename: Bujin
authors.initials: B
authors.lastname: Guo
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: C
authors.initials: C
authors.lastname: Peng
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: G
authors.initials: G
authors.lastname: Luo
authors.forename: H
authors.initials: H
authors.lastname: Le
authors.forename: C
authors.initials: C
authors.lastname: Gmachl
authors.forename: D
authors.initials: D
authors.lastname: Sivco
authors.forename: M
authors.initials: M
authors.lastname: Peabody
authors.forename: A
authors.initials: A
authors.lastname: Cho