<i>In situ</i> tuning of a photonic band gap with laser pulses

Abstract

We report on light-induced optical tuning of colloidal photonic crystals doped with gold nanoparticles (Au-nps). By resonantly exciting the Au-np surface plasmon absorption with picosecond pulses at 0.53μm in a standard pump-probe setup, we observed permanent changes in the stop band resonance around 1.7μm, with blue wavelength shifts as large as 30nm and associated to a nanoparticle reshaping. Fine tuning was achieved by controlling either the pulse energy or the irradiation time.