Generation of Narrow-Bandwidth Paired Photons: Use of a Single Driving Laser

Kolchin, Pavel; Du, Shengwang; Belthangady, Chinmay; Yin, G. Y.; Harris, S. E.

doi:10.1103/physrevlett.97.113602

Cited by 157 publications

(131 citation statements)

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“…The generation rate of paired photons is about 2 × 10 5 pairs per second, with a ratio of paired to anti-Stokes photons of about 75%. These results are in agreement with theory [17,18] and no longer exhibit the discrepancy reported in [17,20,23]. With τ as the relative delay between Stokes and antiStokes detection times t 1 and t 2 respectively, and T b as the bin width, the Glauber correlation function is related to the coincidence rate, R c (τ ) by G (2) …”

Section: Eo Light Modulatorsupporting

confidence: 80%

Electro-Optic Modulation of Single Photons

et al. 2008

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We use the Stokes photon of a biphoton pair to set the time origin for electro-optic modulation of the wave function of the anti-Stokes photon thereby allowing arbitrary phase and amplitude modulation. We demonstrate conditional single-photon wave functions composed of several pulses, or instead, having gaussian or exponential shapes.PACS numbers: 42.50. Gy, 32.80.Qk, 42.50.Ex, 42.65.Lm This letter demonstrates how single photons may be modulated so as to produce photon wave functions whose amplitude and phase are functions of time. The essential feature of this work is the use of one photon of a biphoton pair that is generated by spontaneous parametric down-conversion to establish the time origin for the modulation of the second photon. This is done by using electromagnetically induced transparency and slow light to produce time-energy entangled biphotons with pulse lengths of several hundred ns, and therefore, very long as compared to the temporal resolution of single photon counting modules (about 40 ps). Once the time origin is established, the photon waveform may be modulated in the same manner as one modulates a classical pulse of light. For example, the single-photon waveform may be phase, frequency, amplitude, or even digitally modulated, with the maximum modulation frequency limited by the resolution of the detection of the first photon.As shown in Fig. 1, we use cw pump and coupling lasers to generate time-energy entangled pairs of Stokes and anti-Stokes photons that propagate in opposite directions and are collected in single mode fibers. The detection of a Stokes photon at D 1 sets the time origin for firing the function generator that drives the electro-optic modulator (EOM) that modulates the wave function of the anti-Stokes photon. This latter photon is incident on the beam splitter where it is detected by D 2 or D 3 . As shown in the following, we generate single photons whose modulated waveform is two rectangular pulses, is Gaussian or is a time reversed exponential.The method demonstrated in this letter might be used to optimally load a single photon into an optical cavity [1], or instead, to study the transient response of atoms to different single photon waveforms. In the context of light-matter interfaces, it may improve the efficiency of storage and retrieval of single photons in atomic ensembles [2]. For quantum information applications, both amplitude and phase modulators could be used to allow full control over the single photon waveforms. For example, one could a construct a single photon waveform that is a train of identical pulses with information encoded into the relative phase difference between consecutive pulses [3].The generation of single photons with controlled wave- forms has been demonstrated earlier by using the techniques of cavity-QED, i.e., by coupling a single trapped ion to a high Q cavity and using an acousto-optic modulator to shape a pumping laser that is tuned close to the resonant transition [4]. In related work Rempe and colleagues use a single Rb atom, again i...

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Section: Eo Light Modulatorsupporting

confidence: 80%

Electro-Optic Modulation of Single Photons

et al. 2008

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“…With a cold atomic ensemble as the nonlinear medium, the dephasing rate of χ ð3Þ is comparable to the atomic natural linewidth [29][30][31][32][33][34]. In particular, the biphotons generated from spontaneous fourwave mixing (SFWM) in cold atomic ensembles have a coherence time exceeding 1 μs [35,36] with the electromagnetically induced transparency (EIT) effect [37].…”

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Temporal Purity and Quantum Interference of Single Photons from Two Independent Cold Atomic Ensembles

Qian

Cao

et al. 2016

Phys. Rev. Lett.

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The temporal purity of single photons is crucial to the indistinguishability of independent photon sources for the fundamental study of the quantum nature of light and the development of photonic technologies. Currently, the technique for single photons heralded from time-frequency entangled biphotons created in nonlinear crystals does not guarantee the temporal-quantum purity, except using spectral filtering. Nevertheless, an entirely different situation is anticipated for narrow-band biphotons with a coherence time far longer than the time resolution of a single-photon detector. Here we demonstrate temporally pure single photons with a coherence time of 100 ns, directly heralded from the time-frequency entangled biphotons generated by spontaneous four-wave mixing in cold atomic ensembles, without any supplemented filters or cavities. A near-perfect purity and indistinguishability are both verified through Hong-Ou-Mandel quantum interference using single photons from two independent cold atomic ensembles. The time-frequency entanglement provides a route to manipulate the pure temporal state of the single-photon source. DOI: 10.1103/PhysRevLett.117.013602 The purity of the quantum state of a single photon is a prerequisite of its indistinguishability with single photons from other independent sources, and the latter is an essential basis for the realization of a scalable quantum network with distant and independent nodes [1][2][3][4][5]. Furthermore, the temporal purity of a single photon is crucial to the development of photonic technologies for quantum information science [6,7]. The traditional method to produce indistinguishable single photons is heralding time-frequency entangled biphotons generated from spontaneous parametric down-conversion (SPDC) in a nonlinear crystal which is pumped by ultrashort pulses [4,5,8]. In recent decades many new physical systems have been developed [9-13] to obtain pure single photons without time-frequency entanglement built in.In the community of quantum communication, SPDC in χ ð2Þ nonlinear media is still the preferable way to produce entangled biphotons because of its simplicity in the operation and the potential for on-chip integration and scaling up [14][15][16]. However, the intrinsic feasible phase matching condition of SPDC crystal allows an extremely broad range of temporal modes. Therefore, the typical temporal coherence time of the photon source is of femtosecond scale. Compared to the time response of most commercial single-photon detectors, which is about 1 ns, this temporal coherence time is so short that the trigger photon of the heralded single photon is measured with a large time uncertainty. This time uncertainty damages the temporal quantum purity of the single-photon source. To circumvent the time uncertainty problem due to the slowness of the detectors, a common practice is to use external spectral filtering including passive filtering with narrowband filters [4,5,17] and active filtering with an optical cavity [18]. In this case, the temporal state o...

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“…The technique to control the waveform of entangled photon pairs reported here can be of great interest for enhancing waveform control of paired photons generated through two-photon Raman transitions in electromagnetically induced transparency schemes [23], where highly noncollinear configurations are frequently used [24] and a rudimentary waveform control is demonstrated.…”

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confidence: 99%

Shaping the Waveform of Entangled Photons

et al. 2007

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We demonstrate experimentally the tunable control of the joint spectrum, i.e. waveform and degree of frequency correlations, of paired photons generated in spontaneous parametric downconversion. This control is mediated by the spatial shape of the pump beam in a type-I noncollinear configuration. We discuss the applicability of this technique to other sources of frequency entangled photons, such as electromagnetically induced Raman transitions. PACS numbers:The quantum description of paired photons includes the spatial shape, the polarization state and the joint spectrum. The later contains all the information about bandwidth, type of frequency correlations and waveform of the two-photon state. Quantum light has been proved to be useful in many quantum information applications and the most appropriate form of the joint spectrum depends on the specific realization under consideration. For example, uncorrelated pairs of photons can be used as a source of heralded single photons with a high degree of quantum purity [1,2]; the tolerance against the effects of mode mismatch in linear optical circuits can be enhanced by using photons with appropriately tailored waveform shape [3]; the use of frequency-correlated or anticorrelated photons allows erasing the distinguishing information coming from the spectra when considering polarization entanglement [4,5]; some protocols for quantum enhanced clock synchronization and positioning measurements rely on the use of frequency anticorrelated [6] or correlated photons [7]. Moreover, the entanglement in the frequency domain offers by itself a new physical resource where to explore quantum physics in a high-dimensional Hilbert space [8]. This requires the development of new techniques for the control of the joint spectrum that will allow the generation of multidimensional waveform alphabets.The most widely used method for the generation of pairs of entangled photons is spontaneous parametric down conversion (SPDC). Notwithstanding, paired photons with the desired joint spectrum may not be harvested directly at the output of the downconverting crystal. The question that arises is how to control independently different aspects of the joint spectrum of entangled paired photons generated in SPDC; importantly, the sought-after techniques should work for any frequency band of interest and any nonlinear crystal.Various methods have been proposed and developed to control the type of frequency correlations and the bandwidth of downconverted photons. Some of these methods rely on an appropriate selection of the nonlinear crystal length and its dispersive properties [4,9]. Others are based on SPDC pumped by pulses with angular dispersion [10] or the design of nonlinear crystal superlattices [11]. Noncollinear SPDC has also been propose as a way to tailor the waveform of the downconverted photons [12,13,14,15,16,17]. Contrary to the case of collinear SPDC, where the transverse spatial shape of the pump beam translate into specific features of the spatial waveform of the two-photon state; in...

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Generation of Narrow-Bandwidth Paired Photons: Use of a Single Driving Laser

Cited by 157 publications

References 11 publications

Electro-Optic Modulation of Single Photons

Electro-Optic Modulation of Single Photons

Temporal Purity and Quantum Interference of Single Photons from Two Independent Cold Atomic Ensembles

Shaping the Waveform of Entangled Photons

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