title: Measurement of pump-induced transient lensing in a cryogenically-cooled high average power Ti:sapphire amplifier.
abstract: The transient thermal lensing in a liquid-nitrogren cooled kilohertz multipass amplifier is quantitatively measured with spatially-resolved Fourier transform spectral interferometry. A pump-probe arrangement allows the observation of a polarization-dependent non-thermal component following the fluorescence timescale: additional cooling would not suppress this residual lensing. We also observe a time-dependent thermal component that has a timescale sufficiently fast to indicate that there is cooling between shots even at a repetition rate of 1 kHz. The value of pump-induced lensing would be underestimated when performing time-averaged measurements of pump-induced phase shifts.
authors: Colorado School of Mines, Golden, Colorado 80401, USA. tplancho@mines.edu
authors: Thomas A
authors: TA
authors: Planchon
authors: Wafa
authors: W
authors: Amir
authors: Colby
authors: C
authors: Childress
authors: Jeff A
authors: JA
authors: Squier
authors: Charles G
authors: CG
authors: Durfee
mesh_terms: D000669:Amplifiers, Electronic; D003080:Cold Temperature; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D007909:Lenses; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity