We present an experiment where a single molecule strongly affects the amplitude and phase of a laser field emerging from a subwavelength aperture. We achieve a visibility of -6% in direct and +10% in cross-polarized detection schemes. Our analysis shows that a close to full extinction should be possible using near-field excitation.

We report the zero kinetic energy photoelectron spectrum of the propargyl radical, C3H3. From the spectrum an ionization energy of 69 953±10 cm−1 (8.673 eV) is deduced. Vibrational frequencies are obtained for the totally symmetric normal modes of the propargyl cation, as well as some combination and overtone bands. Both the frequencies and the relative intensities agree well with the predictions from recent ab initio calculations.

Abstract:We demonstrate two solid-state sources of indistinguishable single photons. High resolution laser spectroscopy and optical microscopy were combined at T = 1.4 K to identify individual molecules in two independent microscopes. The Stark effect was exploited to shift the transition frequency of a given molecule and thus obtain single photon sources with perfect spectral overlap. Our experimental arrangement sets the ground for the realization of various quantum interference and information processing experiments.

Employing our recently introduced IR + UV double resonance scheme for obtaining mass-resolved infrared spectra, we have recorded the isotopomer selected N ) 2 CH chromophore absorption of 12 C 6 H 6 and 13 C 12 C 5 H 6 near 6000 cm -1 in a supersonic jet expansion of the benzene isotopomer mixture at natural abundance. The 13 C 12 C 5 H 6 spectra are the first of this kind reported in the literature. For 13 C 12 C 5 H 6 , a preliminary analysis yields an approximate decay time of vibrational excitation τ g 130 fs, which is presumably due to strong anharmonic Fermi resonances between CH-stretching and CH-bending modes. The 12 C 6 H 6 spectrum is compatible with a proposed model of intramolecular vibrational redistribution with a distinct hierarchy of time scales: the CH-stretching state is the IR chromophore state coupled to the IR field. With a decay time of τ ≈ 100 fs, vibrational excitation is redistributed to a first tier of vibrational states, probably CH-stretching/ bending combination bands coupled by strong Fermi resonances. Vibrational excitation is then further redistributed with τ ≈ 0.35 ps to a second tier of states by weaker anharmonic resonances. The observed line widths give a lower bound for the decay time into the dense background manifold, τ > 1.3 ps. Although the experimental jet spectra of 12 C 6 H 6 are in qualitative agreement with previously published calculated spectra, they disagree in finer details.

We report on the triggered generation of indistinguishable photons by solid-state single-photon sources in two separate cryogenic laser scanning microscopes. Organic fluorescent molecules were used as emitters and investigated by means of high resolution laser spectroscopy. Continuous-wave photon correlation measurements on individual molecules proved the isolation of single quantum systems. By using frequency selective pulsed excitation of the molecule and efficient spectral filtering of its emission, we produced triggered Fourier-limited single photons. In a further step, local electric fields were applied to match the emission wavelengths of two different molecules via Stark effect. Identical single photons are indispensible for the realization of various quantum information processing schemes proposed. The solid-state approach presented here prepares the way towards the integration of multiple bright sources of single photons on a single chip.