title: Development of a broadband picosecond infrared spectrometer and its incorporation into an existing ultrafast time-resolved resonance Raman, UV/visible, and fluorescence spectroscopic apparatus.
abstract: We have constructed a broadband ultrafast time-resolved infrared (TRIR) spectrometer and incorporated it into our existing time-resolved spectroscopy apparatus, thus creating a single instrument capable of performing the complementary techniques of femto-/picosecond time-resolved resonance Raman (TR3), fluorescence, and UV/visible/infrared transient absorption spectroscopy. The TRIR spectrometer employs broadband (150 fs, approximately 150 cm(-1) FWHM) mid-infrared probe and reference pulses (generated by difference frequency mixing of near-infrared pulses in type I AgGaS2), which are dispersed over two 64-element linear infrared array detectors (HgCdTe). These are coupled via custom-built data acquisition electronics to a personal computer for data processing. This data acquisition system performs signal handling on a shot-by-shot basis at the 1 kHz repetition rate of the pulsed laser system. The combination of real-time signal processing and the ability to normalize each probe and reference pulse has enabled us to achieve a high sensitivity on the order of deltaOD approximately 10(-4) - 10(-5) with 1 min of acquisition time. We present preliminary picosecond TRIR studies using this spectrometer and also demonstrate how a combination of TRIR and TR3 spectroscopy can provide key information for the full elucidation of a photochemical process.
authors.affiliation: Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Towrie
authors.forename: David C
authors.initials: DC
authors.lastname: Grills
authors.forename: Joanne
authors.initials: J
authors.lastname: Dyer
authors.forename: Julia A
authors.initials: JA
authors.lastname: Weinstein
authors.forename: Pavel
authors.initials: P
authors.lastname: Matousek
authors.forename: Robin
authors.initials: R
authors.lastname: Barton
authors.forename: Philip D
authors.initials: PD
authors.lastname: Bailey
authors.forename: Naresh
authors.initials: N
authors.lastname: Subramaniam
authors.forename: Wai M
authors.initials: WM
authors.lastname: Kwok
authors.forename: Chensheng
authors.initials: C
authors.lastname: Ma
authors.forename: David
authors.initials: D
authors.lastname: Phillips
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Parker
authors.forename: Michael W
authors.initials: MW
authors.lastname: George
mesh_terms: D004247:DNA / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D015335:Molecular Probes; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods; D011786:Quality Control; D012815:Signal Processing, Computer-Assisted; D013050:Spectrometry, Fluorescence / Q000295:instrumentation* / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000295:instrumentation* / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000295:instrumentation* / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods; D018511:Systems Integration
chemical_list: D015335:Molecular Probes; D004247:DNA