Broadband pump-probe spectroscopy at 20-MHz modulation frequency

作者：Preda Fabrizio; Kumar Vikas; Crisafi Francesco; del Valle Diana Gisell Figueroa; Cerullo Giulio; Polli Dario^*

来源：Optics Letters, 2016, 41(13): 2970-2973.

DOI：10.1364/OL.41.002970

We introduce an innovative high-sensitivity broadband pump-probe spectroscopy system, based on Fourier-transform detection, operating at 20-MHz modulation frequency. A common-mode interferometer employing birefringent wedges creates two phase-locked delayed replicas of the broadband probe pulse, interfering at a single photo-detector. A single-channel lock-in amplifier demodulates the interferogram, whose Fourier transform provides the differential transmission spectrum. Our approach combines broad spectral coverage with high sensitivity, due to high-frequency modulation and detection. We demonstrate its performances by measuring two-dimensional differential transmission maps of a carbon nanotubes sample, simultaneously acquiring the signal over the entire 950-1350 nm range with 2.7.10(-6) rms noise over 1.5 s integration time.

• 出版日期2016-7-1