Detection of multimode spatial correlation in PDC and application to the absolute calibration of a CCD camera

Brida, G.; Degiovanni, I. P.; Genovese, M.; Rastello, María Luisa; Berchera, I. Ruo

doi:10.1364/oe.18.020572

Cited by 74 publications

(86 citation statements)

References 28 publications

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“…The high-gain PDC process is also in the focus of attention for its potential applications. For instance, high-gain PDC has been used for quantum imaging [25], ghost imaging [26], and absolute calibration of photo-detectors [27,28]. The possibility to involve such bright states in interactions with material quantum objects (atoms, molecules, quantum dots) has been also addressed.…”

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Coherence properties of high-gain twin beams

et al. 2014

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Twin-beam coherence properties are analyzed both in the spatial and spectral domains at high-gain regime including pump depletion. The increase of the size of intensity auto-and cross-correlation areas at increasing pump power is replaced by a decrease in the pump depletion regime. This effect is interpreted as a progressive loss in the mode selection occurring at high-gain amplification. The experimental determination of the number of spatio-spectral modes from g (2) -function measurements confirms this explanation. The process of parametric down-conversion (PDC) in bulk nonlinear crystals generates twin-beam states of light that are naturally multi-mode both in spectrum and space [1]. Many works, performed in the single-photon regime, have highlighted the correlations and coherence properties of photon pairs either in spectrum or space [2][3][4][5][6][7][8][9]. In the past ten years, also high-gain PDC, leading to a large number of photons per mode, has been the object of several studies for its interesting properties of subshot-noise spatial intensity correlations [10][11][12][13] and macroscopic entanglement [14][15][16][17][18][19]. More recently, the spectral features of macroscopic twin-beam states have been investigated in the collinear interaction geometry close to frequency degeneracy [20]. Moreover, in the high-gain regime, the X-shaped coherence of the PDC output field [21] and the X-shaped spatio-temporal twin beam near-field correlations [22][23][24], originating from the space-time coupling in the phase-matching, have been demonstrated. The high-gain PDC process is also in the focus of attention for its potential applications. For instance, high-gain PDC has been used for quantum imaging [25], ghost imaging [26], and absolute calibration of photo-detectors [27,28]. The possibility to involve such bright states in interactions with material quantum objects (atoms, molecules, quantum dots) has been also addressed. Also the application of twin beams to quantum memories has been recently suggested [29].In this paper, we present a joint investigation of spatial and spectral features of twin-beam states produced in the high-gain regime with non-negligible pump depletion. The coherence properties at different values of pump mean power are inferred by evaluating the intensity auto-and cross-correlation functions on single-shot images of the far-field (θ, λ) speckle-like pattern of the PDC radiation. The initial increase with PDC gain of the size of coherence areas, both in spectrum and space, gradually stops and, at a certain pump power, is replaced by a decrease. This behavior is due to the occurrence of a progressive pump depletion, which is testified by the evolution of the spatial and spectral pump beam profiles. A possible explanation can be given in terms of the varying population of Schmidt paired modes [30] that 'diagonalize' the nonlinear interaction. The number of effectively populated modes is experimentally accessed by the measurement of spatio-spectral intensity g (2) -correlation function. T...

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Coherence properties of high-gain twin beams

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“…We equalize the gains of the detectors to compensate for the excess noise caused by the thermal statistics of the detected beams [20]. The value in the denominator is the shot-noise calibration for the given values N 1 , N 2 and k measured with the coherent light.…”

Section: Heralded Source Of Bright Multi-mode Mesoscopic Sub-poissonimentioning

confidence: 99%

Heralded source of bright multi-mode mesoscopic sub-Poissonian light

et al. 2016

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“…The method in [30] is based on the sub-shot-noise measurement of photon number correlation between a pair…”

Section: Pacs Numbers: Valid Pacs Appear Herementioning

confidence: 99%

“…However, a single photon can not be distinguished from the noise and the time resolution does not allow time tagging and coincidence of photon arrivals, instead the signal is proportional to the intensity (analog regime). If a light signal generate N photo-electron, under the condition ∆ RN << N 1/2 , sub-shot-noise sensitivity can be achieved [31][32][33], a properties that has been used also for quantum enhanced sensing and imaging protocols [2,33].The method in [30] is based on the sub-shot-noise measurement of photon number correlation between a pair …”

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Absolute calibration of a charge-coupled device camera with twin beams

Meda

Berchera

Degiovanni

et al. 2014

Applied Physics Letters

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We report on the absolute calibration of a CCD camera by exploiting quantum correlation. This novel method exploits a certain number of spatial pairwise quantum correlated modes produced by spontaneous parametric-down-conversion. We develop a measurement model accounting for all the uncertainty contributions, and we reach the relative uncertainty of 0.3% in low photon flux regime. This represents a significant step forward for the characterizaion of (scientific) CCDs used in mesoscopic light regime. PACS numbers: Valid PACS appear hereIntroduction. The development of quantum metrology, imaging and sensing [1-6] based on quantum optical states aim to reach sensitivity beyond classical limits. For this reason it requires new detection strategies in the low light intensity regime (down to few photons), that are far from the ones where traditional radiometry operates [7]. Development of dedicated methods for absolute calibration of detectors in this context is therefore necessary, as it is widely recognised inside the radiometric community [8]. Some specific activities in this context are already on-going [9, 10], in particular related to the calibration of single-photon detectors exploiting the Klyshko's twinphoton technique [11][12][13][14][15][16][17][18] and its developments [19][20][21][22][23][24][25].In particular, demand for precise calibration of detectors both in mesoscopic light regime it is relevant not only from the point of view of the development of quantum technologies, but also for establishing a connection between the light intensity level typical of classical radiometric measurements and the quantum radiometry operating at single-photon level [8, 9]. Quantum correlations in twin beams offer an opportunity for reaching this goal, as discussed in [26][27][28][29].In [30] we realized the first absolute calibration of a standard CCD camera by exploiting bright squeezed vacuum. Standard CCD cameras, i.e. without any avalanche electro-multiplication, are able to count the number of generated photo-electron in each pixels for a given exposure time with a read-out noise ∆ RN of few photoelectron (for top-level devices), independent of the exposure time. However, a single photon can not be distinguished from the noise and the time resolution does not allow time tagging and coincidence of photon arrivals, instead the signal is proportional to the intensity (analog regime). If a light signal generate N photo-electron, under the condition ∆ RN << N 1/2 , sub-shot-noise sensitivity can be achieved [31][32][33], a properties that has been used also for quantum enhanced sensing and imaging protocols [2,33].The method in [30] is based on the sub-shot-noise measurement of photon number correlation between a pair

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Detection of multimode spatial correlation in PDC and application to the absolute calibration of a CCD camera

Cited by 74 publications

References 28 publications

Coherence properties of high-gain twin beams

Coherence properties of high-gain twin beams

Heralded source of bright multi-mode mesoscopic sub-Poissonian light

Absolute calibration of a charge-coupled device camera with twin beams

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