TY - GEN
T1 - Mid-infrared microspectroscopic imaging with a Quantum Cascade Laser
AU - Yeh, Kevin
AU - Schulmerich, Matthew
AU - Bhargava, Rohit
PY - 2013
Y1 - 2013
N2 - Conventional mid-infrared (mid-IR) Fourier transform infrared (FT-IR) spectroscopic imaging systems employ an incoherent globar source and achieve spectral contrast through interferometry. While this approach is suitable for many general applications, recent advancements in broadly tunable external cavity Quantum Cascade Lasers (QCL) offer new approaches to and new possibilities for mid-IR micro-spectroscopic imaging. While QCL-based devices have yet to achieve the wide spectral range generally employed by spectroscopists for molecular analyses, they are starting to be used for microscopy at discrete frequencies. Here, we present a discrete frequency IR (DFIR) microscope based on a QCL source and explore its utility for mid-IR imaging. In our prototype instrument, spectral contrast is achieved by tuning the QCL to bands in a narrow spectral region of interest. We demonstrate wide-field imaging employing a 128x128 pixel liquid nitrogen cooled mercury cadmium telluride (MCT) focal plane array (FPA) detector. The resulting images demonstrate successful imaging as well as several unique features due to coherence effects from the laser source. Here we discuss the effects of this coherence and compare our instrument to conventional mid-IR imaging instrumentation.
AB - Conventional mid-infrared (mid-IR) Fourier transform infrared (FT-IR) spectroscopic imaging systems employ an incoherent globar source and achieve spectral contrast through interferometry. While this approach is suitable for many general applications, recent advancements in broadly tunable external cavity Quantum Cascade Lasers (QCL) offer new approaches to and new possibilities for mid-IR micro-spectroscopic imaging. While QCL-based devices have yet to achieve the wide spectral range generally employed by spectroscopists for molecular analyses, they are starting to be used for microscopy at discrete frequencies. Here, we present a discrete frequency IR (DFIR) microscope based on a QCL source and explore its utility for mid-IR imaging. In our prototype instrument, spectral contrast is achieved by tuning the QCL to bands in a narrow spectral region of interest. We demonstrate wide-field imaging employing a 128x128 pixel liquid nitrogen cooled mercury cadmium telluride (MCT) focal plane array (FPA) detector. The resulting images demonstrate successful imaging as well as several unique features due to coherence effects from the laser source. Here we discuss the effects of this coherence and compare our instrument to conventional mid-IR imaging instrumentation.
KW - Chemical imaging
KW - Discrete frequency infrared (DFIR)
KW - Fourier transform infrared (FT-IR)
KW - Microscopy
KW - Mid-infrared spectroscopy
KW - Quantum Cascade Laser (QCL)
UR - http://www.scopus.com/inward/record.url?scp=84881153768&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84881153768&partnerID=8YFLogxK
U2 - 10.1117/12.2015984
DO - 10.1117/12.2015984
M3 - Conference contribution
AN - SCOPUS:84881153768
SN - 9780819495174
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Next-Generation Spectroscopic Technologies VI
T2 - Next-Generation Spectroscopic Technologies VI
Y2 - 29 April 2013 through 30 April 2013
ER -