Intense few-cycle mid-infrared laser source

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The study of strong field phenomena in solids can tremendously benefit from the use of intense, few-cycle laser sources in the mid-infrared part of the spectrum. Lasers at the mid-infrared are more appropriate for exercising strong fields in low band gap materials such as semiconductors, light-harvesting perovskites, 2-D materials, as well as materials of biological interest. With an average bandgap energy of the order of 1-2 eV, semiconductors exposed to optical fields (1 eV -2 eV) suffer optical damage before an extreme nonlinear response can be efficiently triggered. Mid-infrared pulses can allow overcoming this barrier. Mid-infrared field and optical fields will allow excitation and probing of more degrees of freedom other than electronic response such as phonons. The combination of mid-infrared pulses and optical attosecond pulses could allow the development of dynamics picoscopy, that is the capability to explore electron dynamics in matter both in space and time. The possibility to drive strong-field emission from nanostructured materials—a new and highly promising research route in our group, can once again benefit from the duration of ultrashort optical pulses but their energy is very close to the typical work function of solids (< 5 eV) imposing once again a formidable limit as to the maximum electric field that can be exercised. We will see bellow that photoemission experiments offering the potential for generating and controlling electron pulses can be dramatically improved if the carrier energy of the driving field shift towards the mid-infrared part of the spectrum. We propose the procurement of a mid-infrared (2 microns), phase-stabilized, few-cycle laser system with energy in the range of ~250 microjoule. This system will play an essential role for a range of studies of strong field phenomena in solids.