Broadband femtosecond circular dichroism spectrometer with white-light polarization control

Rev Sci Instrum. 2010 Apr;81(4):043104. doi: 10.1063/1.3340892.

Abstract

A broadband, femtosecond transient circular dichroism (TRCD) spectrometer has been developed and tested in the wavelength range from 350 to 700 nm. The spectrometer uses a femtosecond probe white light with well-defined circular polarization. The latter is modulated by the polarization of a narrowband seed pulse. We have implemented a dual-beam probe geometry with phase-locked detection technique to increase the signal-to-noise ratio and to reduce optical artifacts. The spectrometer allows the acquisition of TRCD spectra with subpicosecond time resolution and typical noise levels of 10(-4) absorbance units. The performance of this instrument has been demonstrated on bis(merocyanine) nanorod aggregates in tetrahydrofurane/methylcyclohexane solution. The case study confirmed that this spectrometer is effective for the investigation of chiral properties in various molecular and nanostructural systems that have transient spectra in the UV-visible spectral range.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Absorption
  • Artifacts
  • Benzopyrans / chemistry
  • Circular Dichroism / instrumentation*
  • Cyclohexanes / chemistry
  • Equipment Design
  • Furans / chemistry
  • Indoles / chemistry
  • Light*
  • Nanotubes / chemistry
  • Optics and Photonics / instrumentation
  • Solutions / chemistry
  • Spectrum Analysis / instrumentation*
  • Time Factors

Substances

  • Benzopyrans
  • Cyclohexanes
  • Furans
  • Indoles
  • Solutions
  • merocyanine
  • methylcyclohexane