29 research outputs found
Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory
Photonics is a promising platform for quantum technologies. However, photon
sources and two-photon gates currently only operate probabilistically.
Large-scale photonic processing will therefore be impossible without a
multiplexing strategy to actively select successful events. High
time-bandwidth-product quantum memories - devices that store and retrieve
single photons on-demand - provide an efficient remedy via active
synchronisation. Here we interface a GHz-bandwidth heralded single-photon
source and a room-temperature Raman memory with a time-bandwidth product
exceeding 1000. We store heralded single photons and observe a clear influence
of the input photon statistics on the retrieved light, which agrees with our
theoretical model. The preservation of the stored field's statistics is limited
by four-wave-mixing noise, which we identify as the key remaining challenge in
the development of practical memories for scalable photonic information
processing
Enhancing multiphoton rates with quantum memories
Single photons are a vital resource for optical quantum information
processing. Efficient and deterministic single photon sources do not yet exist,
however. To date, experimental demonstrations of quantum processing primitives
have been implemented using non-deterministic sources combined with heralding
and/or postselection. Unfortunately, even for eight photons, the data rates are
already so low as to make most experiments impracticable. It is well known that
quantum memories, capable of storing photons until they are needed, are a
potential solution to this `scaling catastrophe'. Here, we analyze in detail
the benefits of quantum memories for producing multiphoton states, showing how
the production rates can be enhanced by many orders of magnitude. We identify
the quantity as the most important figure of merit in this connection,
where and are the efficiency and time-bandwidth product of the
memories, respectively.Comment: Just over 4 pages, 2 figure
Interferometric autocorrelation in the ultraviolet utilizing spontaneous parametric down-conversion inside an enhancement cavity
Reversible Gelation of Poly(dimethylsiloxane) with Ionic and Hydrogen-Bonding Substituents
Poly(dimethylsiloxane) copolymers containing a small fraction of carboxylic acid or Zn-carboxylate groups were prepared and compared regarding reversible gelation by hydrogen-bonding and ion-pair interaction. The polymers were synthesized by condensation of a t-butylcarboxylate functionalized dichlorosilane with an α,ω-dihydroxy-poly(dimethylsiloxane), followed by thermal cleavage of the ester bond. Neutralization of the resulting carboxylic acid substituents was achieved by addition of Zn (acac)2. Reversible crosslinking was investigated by step stress and oscillating shear experiments. The carboxylic acid containing poly(dimethylsiloxane) became rubberlike upon increasing the temperature and liquified again when it was brought back to room temperature. This observation has been explained tentatively by segregation of the carboxylic acid groups into polar domains at high temperatures [i.e., a behavior like it is observed for systems with a lower critical solution temperature (LCST)]. At ambient temperature, the carboxylic acid groups undergo hydrogen bonding to the Si-O-Si backbone. Clustering of the carboxylic acid groups occurs only as these hydrogen bonds break upon raising temperature. Moisture was found to have a strong influence on the reversal of the crosslinking. Addition of zinc acetylacetonate resulted in the formation of an elastic network already at ambient conditions consistent with the concept of ionomers which undergo reversible gelation by formation of ion-pair multiplets and clusters in the hydrophobic polymer matrix in particularly at low temperatures. At high temperature, both the carboxylic acid and the carboxylate sample exhibited a rather similar viscoelastic behavior consistent with a common structure where transient crosslinks are formed by clusters of the carboxylic acid and the carboxylate groups. © 1999 John Wiley & Sons, Inc
Ultraviolet enhancement cavity for ultrafast nonlinear optics and high-rate multiphoton entanglement experiments
Six-photon entangled Dicke state enabled by a UV enhancement cavity as novel SPDC photon source
Storage of Light in a Hollow-Core Photonic-Crystal Fibre
We report the storage and retrieval of broadband optical pulses using a Raman interaction in a room-temperature ensemble of cesium atoms confined in a hollow-core photonic-crystal fibre. (C) 2013 Optical Society of Americ
Broadband single-photon-level memory in a hollow-core photonic crystal fibre
Storing information encoded in light is critical for realizing optical buffers for all-optical signal processing(1,2) and quantum memories for quantum information processing(3,4). These proposals require efficient interaction between atoms and a well-defined optical mode. Photonic crystal fibres can enhance light-matter interactions and have engendered a broad range of nonlinear effects(5); however, the storage of light has proven elusive. Here, we report the first demonstration of an optical memory in a hollow-core photonic crystal fibre. We store gigahertz-bandwidth light in the hyperfine coherence of caesium atoms at room temperature using a far-detuned Raman interaction. We demonstrate a signal-to-noise ratio of 2.6:1 at the single-photon level and a memory efficiency of 27 +/- 1%. Our results demonstrate the potential of a room-temperature fibre-integrated optical memory for implementing local nodes of quantum information networks