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 Title: SINGLE-SHOT SUB-MICROSECOND SPECTROSCOPY OF THE BACTERIORHODOPSIN PHOTOCYCLE WITH QUANTUM CASCADE LASER FREQUENCY COMBS Author(s): Mangold, Markus Contributor(s): Faist, Jerome; Allmendinger, Pitt; Hugi, Andreas; Klocke, Jessica; Kottke, Tilman Subject(s): Mini-symposium: Frequency-Comb Spectroscopy Abstract: Time-resolved vibrational spectroscopy is an important tool for understanding biological processes and chemical reaction pathways [1]. Today, all available methods to our knowledge require many repetitions of an experiment to acquire a microsecond time-resolved mid-infrared spectrum. We present the IRspectrometer, a quantum cascade laser dual frequency comb spectrometer [2-3]. It allows for parallel acquisition of hundreds of mid-infrared wavelengths with microsecond time resolution. The formation of the light-activated L, M and N-states in bacteriorhodopsin – which only have $\mu$s to ms lifetimes – has been recorded by analyzing the infrared response of bacteriorhodopsin to 10 ns visible light pulses with sub-microsecond time-resolution. The different wavelengths were all measured in parallel thanks to the dual-comb approach. The spectra as well as the kinetics show good agreement with those from step-scan FT-IR measurements. As a benchmark, the spectral signature of several intermediate states of the bacteriorhodopsin photocycle has been recorded in a single shot measurement. This approach greatly reduces the complexity of time-resolved spectroscopy measurements in the mid-infrared which currently require many repetitions. References [1] Ritter, E. et al. “Time-Resolved Infrared Spectroscopic Techniques as Applied to Channelrhodopsin.” Front. Mol. Biosci. 2:38. [2] Hugi, A. et al. “Mid-Infrared Frequency Comb Based on a Quantum Cascade Laser.” Nature 492: 229–33 [3] Villares, G. et al. “Dual-comb spectroscopy based on quantum-cascade-laser frequency combs.” Nat. Commun. 5:5192 Issue Date: 06/19/18 Publisher: International Symposium on Molecular Spectroscopy Citation Info: APS Genre: Conference Paper / Presentation Type: Text Language: English URI: http://hdl.handle.net/2142/100785 DOI: 10.15278/isms.2018.TG03 Other Identifier(s): TG03 Date Available in IDEALS: 2018-08-172018-12-12
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