Members of the Academic Staff

Ultrafast Optics

  • Jesús Garduño-Mejía
  • Carlos J. Román-Moreno

Ultrafast optics is related with the generation, characterization, manipulation and applications of ultrashort laser pulses.

An ultrashort laser pulse is an electromagnetic field burst with a time duration in the sub-picosecond temporal regime (<10-12 sec), containing high peak powers in the order of KW up to PW. Such laser pulses, concentrated in space, provide different applications in many important fields and modern technology, such as medicine (micro-surgery and high resolution imagenology, Optical coherent tomography), biology (nonlinear microscopy), chemistry (ultrafast dynamics and quantum control trough time resolved spectroscopy and pulse shaping), physics (nonlinear optics, quantum optics, high intense light–matter interaction for X-ray generation and fusion, attosecond pulse generation, super continuum generation, quantum optics, optical combs, optical communications, THZ radiation generation, among others), in the industry for micromachining and drilling applications, etc.

Group’s Research Interests:

  • Femtosecond laser sources development (design and construction)
  • Spatio-temporal characterization systems for ultrashort pulses
  • Pulse shaping
  • Applications

Femtosecond Laser Sources and Spatio-Temporal Characterization Systems Development

To date, Kerr lens mode locked KLML Ti:Sapphire laser represents the most standard and reliable tool for femtosecond optical pulses generation, capable to deliver peak powers up to KW. If the pulses are amplified, peak power can reach up to PW. Part of the Group’s interest is the development of (home-made) femtosecond pulses sources and characterization systems (phase and amplitude). So far we have developed different fs laser systems: KLML Ti:Sapphire, erbium-doped fiber lasers (EDFL), erbium-doped fiber amplifiers (EDFA) and optical parametric oscillators. The process of optical parametric frequency conversion in a femtosecond-optical parametric oscillator (fs-OPO) is particularly attractive since it offers tunable pulses in the near-infrared (NIR) spectral region. The characterization systems we have developed in the Group consist in frequency resolved optical gating (FROG), SPIDER, TADPOLE, and nonlinear autocorrelation. A very important task of the Group, in collaboration with the Optical Instrumentation Group of ICAT-UNAM, consists in improving its efficiency, in terms of pump threshold, and the enhancement of the peak intensity at the focal point, based on aberration compensation. Maximum peak intensity is fundamental in applications where, for instance, maximum linear and nonlinear optical effects are required. In practice, because of the large pulse bandwidth and the finite transversal size of the femtosecond pulses, aberrations come into play, preventing diffraction-limited focusing and introducing a radius-dependent time intensity distribution. Spreading spatial-temporal effects will depend strongly on the input pulse characteristics and on the specific lens system design. The main contributions for spatial–temporal pulse spreading in the vicinity of the focal point are the group velocity dispersion (GVD), the propagation time difference (PTD), and the spherical aberration (for a collimated beam parallel to the optical axis). We have developed numerical models and diagnostic systems to study such effects.

Pulse Shaping

Femtosecond pulse shaping is typically achieved by different techniques which involve a phase or intensity modulator such as a liquid-crystal display (LCD) array, acousto-optic programmable dispersive filters (AOPDF), and micro-machined deformable membrane mirrors (MMDM) located at the Fourier plane where the spectral components of the pulse are deployed. Part of our work also involves pulse shaping, applying MMDM and spatial modulators guided for evolutionary algorithms and soft computing. Our main task is to eliminate the dispersive effects suffered for the pulses when propagated through optical systems.


Because of its particular characteristics in terms of temporal resolution, spatial resolution, high peak power and ultra broadband bandwidth, ultrashort pulses  have been demonstrated to be effective tools for different applications as nonlinear microscopy, ultrafast dynamics study, optical coherent tomography, telecommunications, super continuum generation, nonlinear optics, non-thermal material processing, etc. The group’s interests are related to time-resolved spectroscopy in metals and semiconductors, nonlinear microscopy and material processing.