We report on a novel near-field microscope in which ultrashort laser pulses are coupled into hollow-pyramid cantilever probes. The high throughput, absence of polarization pinning and absence of chirping, which are premium features of such probes, enable obtaining sufficient peak power in the near-field to perform nonlinear optical experiments. We show experimental results on second-harmonic generation from metal nanostructures and two-photon excitation of fluorescent conjugated polymers on the subwavelength scale.
Biagioni, P;  Celebrano, M;  Polli, D;  Labardi, M;  Zavelani-Rossi, M;  Cerullo, G;  Finazzi, M;  Duo, L 
- Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan (Italy)
- Istituto di Fotonica e Nanotecnologie, CNR, Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133 Milan (Italy)
- PolyLab CNR-INFM, largo Bruno Pontecorvo 3, 56127 Pisa (Italy)