Related papers: Experimental investigation of delayed self-interfe…
When a pulse of light traverses a material, it incurs a time delay referred to as the group delay. Should the group delay experienced by photons be attributed to the time they spend as atomic excitations? However reasonable this connection…
Well isolated quantum systems are exquisite sensors of electromagnetic fields. In this work, we use a single trapped ion for characterizing chirped ultraviolet (UV) picosecond laser pulses. The frequency swept pulses resonantly drive a…
We demonstrate experimentally a scheme to measure small temporal delays, much smaller than the pulse width, between optical pulses. Specifically, we observe an interference effect, based on the concepts of quantum weak measurements and weak…
We demonstrate optical interferometry beyond the limits imposed by the photon wavelength using 'triggered' entangled photon pairs from a semiconductor quantum dot. Interference fringes of the entangled biphoton state reveals a periodicity…
We discuss an experimental setup where two laser-driven atoms spontaneously emit photons and every photon causes a ``click'' at a point on a screen. By deriving the probability density for an emission into a certain direction from basic…
We propose an original quantum memory protocol. It belongs to the class of rephasing processes and is closely related to two-pulse photon echo. It is known that the strong population inversion produced by the rephasing pulse prevents the…
A nonlinear quantum-optical process is considered: emission of photon pairs by the reflecting end of a fiber excited by a standing laser wave. Radiation occurs due to periodic changes in the optical length of the fiber over time. This…
Multiphoton interference effects can be measured with a single detector when two input photons are temporally well separated when compared with the dead time of the single-photon avalanche detector. Here we experimentally demonstrate that…
We present measurements of single-photon ionization time delays between valence electrons of argon and neon using a coincidence detection technique that allows for the simultaneous measurement of both species under identical conditions.…
We report experimental observations of interference between three-photon and one-photon excitations, and phase control of light attenuation/transmission in a four-level system. Either constructive interference or destructive interference…
We report on the first results of a search for optical-wavelength photons mixing with hypothetical hidden-sector paraphotons in the mass range between 10^-5 and 10^-2 electron volts for a mixing parameter greater than 10^-7. This was a…
Invariant entangled states remain unchanged under simultaneous identical unitary transformations of all their subsystems. We experimentally generate and characterize such invariant two-, four-, and six-photon polarization entangled states.…
Signals from radio pulsars show a wavelength-dependent delay due to dispersion in the interstellar plasma. At a typical observing wavelength, this delay can vary by tens of microseconds on five-year time scales, far in excess of signals of…
We apply a recently proposed method for the analysis of time series from systems with delayed feedback to experimental data generated by a CO_2 laser. The method is able to estimate the delay time with an error of the order of the sampling…
Single photon, emitted in a transition between two states, has a frequency distribution of intensity, which is given by Lorentzian if the transition is only naturally broadened and the period of observation $T$ is long compared to the…
We study laser-assisted photodetachment time delays by attosecond pulse trains from the closed-shell negative ions F- and Cl-. We investigate the separability of the delay into two contributions: (i) the Wigner-like delay associated with…
We present an experiment where two photonic systems of arbitrary dimensions can be entangled. The method is based on spontaneous parametric down conversion with trains of d pump pulses with a fixed phase relation, generated by a mode-locked…
Ultra-cold atoms trapped in an optical dipole trap and prepared in a coherent superposition of their hyperfine ground states, decohere as they interact with their environment. We demonstrate than the loss in coherence in an "echo"…
Single-photon stimulated four wave mixing (StFWM) processes have great potential for photonic quantum information processing, compatible with optical communication technologies and integrated optoelectronics. In this paper, we demonstrate…
To store and retrieve signals at the single photon level, various photon echo schemes have resorted to complex preparation steps involving ancillary shelving states in multi-level atoms. For the first time, we experimentally demonstrate…