A new femtosecond pump–probe spectroscopy technique is demonstrated that permits the high-speed, parallel acquisition of pump–probe measurements at multiple wavelengths. This is made possible by use of a novel, two-dimensional smart pixel detector array that performs amplitude demodulation in real time on each pixel. This detector array can not only achieve sensitivities comparable with lock-in amplification but also simultaneously performs demodulation of probe transmission signals at multiple wavelengths, thus permitting rapid time- and wavelength-resolved femtosecond pump–probe spectroscopy. Measurements on a thin sample of bulk GaAs are performed across 58 simultaneous wavelengths. Differential probe transmission changes as small as ~2×10-4 can be measured over a 5-ps delay scan in only ~3 min . This technology can be applied to a wide range of pump–probe measurements in condensed matter, chemistry, and biology.
© 2003 Optical Society of America
S. Bourquin, R. P. Prasankumar, F. X. Kärtner, J. G. Fujimoto, T. Lasser, and R. P. Salathé, "High-speed femtosecond pump probe spectroscopy with a smart pixel detector array," Opt. Lett. 28, 1588-1590 (2003)