Compressive Broad-Band Hyperspectral Sum Frequency Generation Microscopy to Study Functionalized Surfaces.
A broad-band sum frequency generation microscope has been developed for the study of molecular monolayers on surfaces. Because sum frequency generation is a vibrational spectroscopy based on a second-order optical process, it is uniquely sensitive to detecting a molecule's vibrational fingerprints specifically at interfaces. In this microscope, a structured illumination beam generated by a spatial light modulator is used to irradiate the sample with a series of sparsifying pseudorandom patterns. The spectra associated with each pattern are then input into a reconstruction algorithm to compressively recover the full hyperspectral image cube. As a proof-of-principle, this system performed molecule-specific imaging of a microcontact-printed self-assembled monolayer of alkanethiolate on copper. This hyperspectral compressive imaging effectively recovered both spatial and spectral surface features with compression greater than 80%, meaning more than a 5-fold decrease in acquisition time compared to traditional methods.
Department of Chemistry, University of Houston , Houston, Texas 77204-5003, United States.
Desheng
D
Zheng
Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States.
Liyang
L
Lu
Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States.
Yun
Y
Li
Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States.
Kevin F
KF
Kelly
Department of Chemistry, University of Houston , Houston, Texas 77204-5003, United States.
Steven
S
Baldelli