Figure 2
From: Phase control of femtosecond pulses on the nanoscale using second harmonic nanoparticles
Femtosecond pulse compression on a single 180-nm BaTiO3 NP. (a) SEM image of the investigated area of a BaTiO3 sample. (b) SH image of the sample area before pulse compression. The circled particle was chosen for pulse compression. (c) SH image of the sample area after pulse compression, measured under identical acquisition settings. Note the total SH intensity increase collected from the NPs (the same color bar applies to both SH images). Red arrows indicate small NPs (mean dimension of 125 nm) that are clearly detectable only after pulse compression. (d) Laser spectrum used in the experiment, together with the spectral phase measured before and after pulse compression. Note that MIIPS successfully compensated for ∼40-rad distortions. (e) SH spectra of the selected NP, as measured for different compensation masks during MIIPS optimization. Note that the SH spectrum after compression agrees very well with the simulated result (dashed black line). (f) Simulated (red dashed line) and measured interferometric autocorrelation (black line) of the compressed 17-fs pulse, as explained in the text. Inset: calculated time profile of the uncompressed (dashed red line) and compressed pulse (solid blue line). MIIPS, multiphoton intrapulse interference phase scan; NP, nanoparticle; SEM, scanning electron microscopy; SH, second harmonic.
