Optically heterodyned coherent Raman spectroscopy

Off-resonant third-order nonlinear optical properties of multiply-bonded multinuclear organometallic complexes measured with femtosecond pulses

“…However, we soon noticed that the features of the OHD-OKE response of the sample, i.e., a negative peak centered at 0 fs with a similar width of the autocorrelation of the laser pulse, were the same as those of a coherent artifact of OHD-OKE measurements reported previously for weakly absorptive media [12][13][14]. The coherent artifact is explained to arise from formation of the grating related to residual absorption, at overlap region between the pump and the probe pulses, which is not considered in the standard OHD-OKE formulation [6]. Therefore, we tried another measurement technique, i.e., Z-scan, at the same wavelength range to clarify if the negative peak can be assigned to the electronic nonlinearity or the coherent artifact.…”

“…OHD-OKE is a sensitive technique to detect either the real part or the imaginary part of the third-order susceptibility, by changing the phase of the local oscillator light [6]. Thus, nonlinear refractive index change (originating from the real part) or nonlinear absorption (from the imaginary part) can be measured independently.…”

“…Thus, nonlinear refractive index change (originating from the real part) or nonlinear absorption (from the imaginary part) can be measured independently. We applied p/2-out-of-phase configuration to detect the real part [6]. The p/2-out-of-phase OHD-OKE is considered to be less affected by thermal change of refractive index.…”

Deformation corrected real-time terahertz imaging

“…In this method, nonuniformity of ⌫ directly affects the uniformity of the obtained image, and the magnitude of ⌫ cannot be controlled although there is an appropriate value of ⌫ for the largest signal modulation depth. 21 In the configuration using a QWP and a tilted analyzer, 15,16,[23][24][25] on the other hand, the transmitted light intensity becomes…”

High sensitivity transient infrared spectroscopy: a UV/Visible transient grating spectrometer with a heterodyne detected infrared probe

“…Another important type of method for heterodyne detection of background-free nonlinear signals is possible when a pump beam induces polarization anisotropy in the sample. Then, a polariser in the probe can be used to 'leak' a local oscillator field onto a detector, collinear with the signal [11,12]. A UV/Visible pump, IR probe technique based on these principles was recently demonstrated by Helbing et al [13], showing more than an order of magnitude enhancement in the anisotropic component of the UV pump, IR probe signal.…”