Ultrafast time-domain spectroscopy system using 10 GHz asynchronous optical sampling with 100 kHz scan rate

Abstract

An ultrafast time-domain spectroscopy system employing asynchronous optical sampling at a repetition rate of 10 GHz is presented. Two ultra-compact Ti:sapphire femtosecond ring lasers allow to achieve scan rates as high as 100 kHz for a 100 ps long time window and a time-delay resolution of 100 fs. The feasibility of this high-speed ASOPS system is evaluated by performing THz time domain spectroscopy on molecular gases where signal-to-noise ratios exceeding 30 dB for averaging times in the millisecond range have been obtained. In order to demonstrate the benefits of this system for ultrafast pump-probe spectroscopy we demonstrate the high-sensitivity detection of coherent acoustic phonons with dephasing times in the range of the 100 ps time window. Konstanzer Online-Publikations-System (KOPS) URL: http://nbn-resolving. de/urn:nbn:de:bsz:352-0-395845 Erschienen in: Optics Express ; 24 (2016 24 ( ), 26. -S. 22930-22940 http://dx.doi.org/10.1364 Graham, "Terahertz cyclotron resonance spectroscopy of an algan/gan heterostructure using a high-field pulsed magnet and an asynchronous optical sampling technique," Appl. Phys. Lett. 108, 212101 (2016). 18. A. Bruchhausen, R. Gebs, F. Hudert, D. Issenmann, G. Klatt, A. Bartels, O. Schecker, R. Waitz, A. Erbe, E. Scheer, J.-R. Huntzinger, A. Mlayah, and T. Dekorsy, "Subharmonic resonant optical excitation of confined acoustic modes in a free-standing semiconductor membrane at GHz frequencies with a high-repetition-rate femtosecond laser," Phys. Rev. Lett. 106, 077401 (2011).

Efficient pump-probe sampling with a single-cavity dual-comb laser: Application in ultrafast photoacoustics

“…This was also implemented for optical spectroscopy applications using slightly different repetition rates for the pump and probe lasers [10] . This type of sampling with two different optical pump and optical probe repetition rates became also known as asynchronous optical sampling (ASOPS) and is now commonly used for ultrafast photoacoustic studies, for example, for scans over 100 ps [11] , 1 ns [12] , 10 ns [13] and 21 ns [14] . We would like to suggest using ETS instead of ASOPS because the pump and probe pulse trains are still synchronized with each other at a small difference in pulse repetition rates.…”

Tunable compact asynchronous optical sampling system using Er-doped fiber laser

“…Asynchronous optical sampling (ASOPS) is another promising solution that employs two mode-locked lasers with slightly different repetition rates to generate and detect pulsed THz radiation [16][17][18][19][20] . Conventionally, Ti:sapphire lasers have been widely used as laboratory light sources for high-speed THz-TDS [21,22] . Polarization-maintaining (PM) fiber lasers feature characteristics that improve the stability and robustness of THz-TDS [23] .…”

Laser Diode based THz-TDS System with 133 dB peak Signal-to-Noise Ratio

“…Recent advances in photoconductive antenna technology increased the bandwidth to 10 THz 10 . Moreover, the introduction of concepts such as asynchronous optical sampling (ASOPS) [11][12][13] , electronically controlled optical sampling (ECOPS) 14 , optical sampling by cavity tuning (OSCAT) 15 , and single-laser polarization-controlled optical sampling (SLAPCOPS) 16 has made it possible to construct THz-TDS systems without a mechanical optical delay unit (ODU). Such systems tend to be more mechanically robust and -more importantly -achieve spectral update rates of up to 100.000 spectra per second 12 .…”