Two‐photon excitation of excitons in CuCl in total reflection geometry

Abstract

SummaryWe have observed emission spectra of a CuCl film on a TiO 2 prism surface(110) associated with the two-photon excitation of the exciton system in total reflection geometry. The I 1 bound exciton emission, which resonantly appeared at the twophoton excitation of the Z 3 -longitudinal excitons and Z 1,2 -exciton band, was observed. The dependence of the emission intensities on the polarization of the excitation light was explained from the field intensity and the penetration depth of the evanescent light in CuCl accompanying the totally reflected light at the TiO 2 /CuCl interface.

Non-linear evanescent-field imaging

“…At present, non-linear EF techniques represent a tiny, if growing, fraction of the recent TIRF literature. 2PEF EF spectroscopy [36][37][38][39][40], two-photon EW pattern photobleaching [22] and 2PEF EF microscopy [20,[41][42][43][44] combine the optical sectioning capacity of EF imaging with a number of advantages that derive from the quadratic intensity dependence of 2PEF (figure 4, bottom): (1) The restriction of fluorescence excitation to a well-defined planar excitation volume V 2ω = 2πw 2 r w z (ϑ)/cos(ϑ) that can be defined in analogy to the familiar cigar-shaped 2PEF excitation volume [20] (see section 2.2). ( 2) The suppression of background fluorescence from scattered excitation photons (figure 5).…”