Using a turn-key Ti:sapphire femtosecond laser frequency comb, an off-the-shelf supercontinuum device and Fabry-Perot mode filters, we report the generation of a 16-GHz frequency comb spanning a 90-nm band about a center wavelength of 566 nm. The light from this astro-comb is used to calibrate the HARPS-N astrophysical spectrograph for precision radial velocity measurements. The comb-calibrated spectrograph achieves a stability of ∼1 cm/s within half an hour of averaging time. We also use the astro-comb as a reference for measurements of solar spectra obtained with a compact telescope and as a tool to study intrapixel sensitivity variations on the spectrograph detector.
A new optical pump-probe technique is implemented for the investigation of acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with 200 femtoseconds resolution at scan rates of 10 kHz. The generation of coherent acoustic phonons and their propagation and decay dynamics are investigated in semiconductor heterostructures, layered nanoscale materials of relevance for microelectronics, and X-ray mirrors. Changes of the optical properties of tailored semiconductor heterostructures associated with coherent phonon dynamics open the pathway for the modulation of optical signals at up to THz frequencies.