Dual frequency comb spectroscopy with a single laser.

We demonstrate a simple scheme for dual frequency comb spectroscopy in which the second frequency comb is generated by propagating the primary pulse train through a dazzler. The two frequency combs are combined behind a Mach-Zehnder interferometer, and the optical spectrum is read out by an rf-spectrum analyzer. The method is applied to record the overtone absorption spectrum of C2H2 (acetylene) in the wavelength region around 1.03 µm. A spectrum with a resolution of 4 cm(-1) is obtained, which compares well with that from the HITRAN database. A simple method for improving the spectral resolution is demonstrated.

Grism compressor for carrier-envelope phase-stable millijoule-energy chirped pulse amplifier lasers featuring bulk material stretcher.

We demonstrate compression of amplified carrier-envelope phase (CEP)-stable laser pulses using paired transmission gratings and high-index prisms, or grisms, with chromatic dispersion matching that of a bulk material pulse stretcher. Grisms enable the use of larger bulk stretching factors and thereby higher energy pulses with lower B-integral in a compact amplifier design suitable for long-term CEP control.

Apparent causality paradox in frustrated Gires-Tournois interferometers.

Negative group delay times upon total reflection from frustrated Gires-Tournois interferometers seem to violate causality. Contrary to what has been recently argued in the literature, I show with the example of total light reflection upon an ideal nonabsorbing plasma that adding the time associated with the Goos-Hänchen shift does not solve the paradox, which remains open.

Amplitude and phase control of ultrashort pulses by use of an acousto-optic programmable dispersive filter: pulse compression and shaping.

We demonstrate experimentally that an arbitrary phase and amplitude profile can be applied to an ultrashort pulse by use of an acousto-optic programmable dispersive filter (AOPDF). Our filter has a large group-delay range that extends over 3 ps and a 30% diffraction efficiency over 150 THz. Experiments were conducted on a kilohertz chirped-pulse amplification laser chain capable of generating 30-fs pulses without additional pulse shaping. Compensating for gain narrowing and residual phase errors with an AOPDF in place of the stretcher results in 17-fs transform-limited pulses. Arbitrary shaping of these 17-fs pulses is also demonstrated in both the temporal and the spectral domains.

Characterization of perpendicular chirped phase volume grating pairs for laser pulse stretching.

We report the characterization of a new pulse stretcher that provides a linear and positive variation of the group delay as a function of the optical frequency. It consists of a perpendicular chirped-grating pair introduced by Tournois [Opt. Commun. 106, 253 (1994)] that allows 20-fs pulses to be stretched to 100 ps. The system is tested by short-pulse spectral interferometry. We designed and realized the chirped gratings by phase volume holographic recording in a highly efficient photopolymer.

Time-domain interferometry for direct electric-field reconstruction by use of an acousto-optic programmable filter and a two-photon detector.

We introduce a new approach to the characterization of femtosecond optical pulses based on a remarkably simple setup combining a two-photon detector and a pulse shaper consisting of a longitudinal acousto-optic programmable filter. The operation of this setup is demonstrated through the use of a new version of spectral phase interferometry for direct electric-field reconstruction based on time-domain instead of on frequency-domain interferometry.