Crossed-beam spectral interferometry: a simple, high-spectral-resolution method for completely characterizing complex ultrashort pulses in real time

Abstract

We present a high-spectral-resolution and experimentally simple version of spectral interferometry using optical fibers and crossed beams, which we call SEA TADPOLE. Rather than using collinear unknown and reference pulses separated in time to yield spectral fringes-and reduced spectral resolution-as in current versions, we use time-coincident pulses crossed at a small angle to generate spatial fringes. This allows the extraction of the spectral phase with the full spectrometer resolution, which allows the measurement of much longer and more complex pulses. In fact, SEA TADPOLE achieves spectral super-resolution, yielding the pulse spectrum with even better resolution. Avoiding collinear beams and using fiber coupling also vastly simplify alignment. We demonstrate SEA TADPOLE by measuring a chirped pulse, a double pulse separated by 14 ps, and a complex pulse comprising two trains of pulses with a time-bandwidth product of ~400.

Interaction of ultrashort-laser pulses with induced undercritical plasmas in fused silica

“…Experimental measurements designed to measure the complete complex field as a function of space and time (see, e.g., the recent methods in Refs. [37][38][39][40][41]) will reduce the need to assumeg an initial field with no spatiotemporal dependences or to use apertured FROG traces. Additionally, recent investigations into the possible role of high-order nonlinear optical effects [42][43][44], ionization by multichromatic pulses [45], and the influence of phenomenological parameters (such as the free-carrier collision time and the effective electron mass) [46] may also allow for further improvements in predamage calculations.…”

What We Can Learn about Ultrashort Pulses by Linear Optical Methods

“…The extended versions of SSRI using arbitrary broadband light source (e.g., white light or ultrashort laser pulses) quickly became a widespread technique. In addition to further measurements on the phase shift of dispersion-compensating chirped mirrors [45,46], SSRI was used among others for pump-and-probe experiments [47], fine adjustment of the stretcher and compressor units of phase-modulated pulse amplifying systems [48], characterization of laser pulses [49][50][51], as well as the investigation of devices controlling the temporal shape of laser pulses [52,53]. Most recently, a high-power passive optical resonator was studied by this technique [54].…”

“…A modified version of crossed-beam interferometry-based techniques combined with SPIDER and FROG methods resulted in the so-called spatially encoded arrangement for temporal analysis by dispersing a pair of light E-fields, SEA-TADPOLE [51]. This method reveals interference patterns almost identical with that of the SSRI methods, although the experimental implementations of the two methods are different.…”

Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal

“…During the last decade different techniques have been implemented and extensively adopted [1][2][3][4] either for partial or/and complete temporal characterization of the pulses. They include for instance, Frequency-Resolved Optical Gating (based on the concept of optical gating) or Spectral Phase Interferometry for Direct Electric-field Reconstruction, (based on the concept of spectral interferometry) or even for 3D characterization (STARFISH, SEA Tadpole) [5][6]. Although a detailed field reconstruction is needed in particular applications and thus fully justifies the use of these advanced techniques, there are still many situations requiring just a partial characterization of the pulse.…”