title: High-sensitivity ultrashort mid-infrared pulse characterization by modified interferometric field autocorrelation.
abstract: We report on spectral phase retrieval of 43 MHz, ∼100  fs, 3.3 μm pulses at energies down to 8.9 pJ by a modified interferometric field autocorrelation method. The simple setup consists of a Michelson interferometer, a 266 μm thick AgGaSe2crystal, and a homemade spectrometer with an InGaAs point detector, which is readily applicable to measuring a 20 fs (1.8 cycles) pulse at 3.3 μm. The feasibility is verified by comparing with the results obtained by simulation and frequency-resolved optical gating for the spectral phase modulation because of a 4 mm thick germanium plate.
authors.forename: Ming-Sung
authors.initials: MS
authors.lastname: Chao
authors.forename: Hsiang-Nan
authors.initials: HN
authors.lastname: Cheng
authors.forename: Bo-Jyun
authors.initials: BJ
authors.lastname: Fong
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Hsieh
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Hsiang
authors.forename: Shang-Da
authors.initials: SD
authors.lastname: Yang