The effect of linewidth on the efficiency of two-photon-pumped frequency converters

Third-Harmonic Generation and Third-Order Frequency Mixing

“…Similar dependences have been obtained by Stappaerts et al 45 and Leubner et ai 47 from analyses in the frequency domain. When homogeneous broadening is dominant the average harmonic intensity is given by while for dominant Doppler broadening the average intensity is These results show that in the limit of large laser linewidths at exact resonance the average harmonic intensity varies inversely with the product of the laser linewidth and the material linewidth.…”

“…The net wave vector mismatch is given by (45) where N t is the concentration of the ith component and the linear susceptibilities may be calculated from the appropriate Sellmeier equation. Positive dispersion will be present in a medium if all the wavelengths lie below the lowest excited level or if the generated wavelength lies close to but below a dispersive level.…”

Invited Article: High resolution angle resolved photoemission with tabletop 11 eV laser

“…3(b) for the 1 MHz repetition rate, 1 ns pulsewidth laser setup, detuning of the UV wave from the two-photon resonance results in a rapid reduction in VUV generation efficiency. 38 The width of this resonance profile is set by the convolution of the laser linewidth and the natural linewidth (including isotopic and Doppler broadening) of the two-photon transition. In order to maintain peak flux, the central frequency of the UV beam must be maintained to within 1 GHz; the IR frequency must therefore be stabilized to the central frequency within 250 MHz uncertainty.…”