title: Single-shot, planar infrared imaging in flames using polarization spectroscopy.
abstract: Planar infrared visualization of species in flames is challenging due to the severe thermal radiation background and relatively weak fluorescence quantum yields from ro-vibration transitions. In this express, we report imaging of molecular species in a flame via an absorption-based coherent optical method, namely infrared polarization spectroscopy (IRPS). Single-shot, planar imaging of hydrogen fluoride (HF) has been achieved in a premixed CH(4)/O(2) Bunsen flame, being seeded with a small amount of SF(6). The HF molecule was excited through a rovibrational transition at around 2.5 µm, which belongs to the fundamental vibration band. High spatial resolution was guaranteed using an orthorgonal pump-probe geometry, and an effective suppression of thermal background emission was achieved owing to the coherent nature of the demonstrated two-dimensional IRPS. Other advantages, e.g. high temporal resolution and species-specificity, are also features of this laser-based technique, which make it suitable for imaging of non-fluorescent but infrared active gaseous molecules in harsh environments.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Sun
authors.forename: Johan
authors.initials: J
authors.lastname: Zetterberg
authors.forename: Zeyad
authors.initials: Z
authors.lastname: Alwahabi
authors.forename: Marcus
authors.initials: M
authors.lastname: Aldén
authors.forename: Zhongshan
authors.initials: Z
authors.lastname: Li