G. Brida, M. Genovese, and M. Gramegna, "Twin-photon techniques for photo-detector calibration," Laser Phys. Lett. 3, 115-123 (2006).

[CrossRef]

M. Genovese, "Research on hidden variable theories: a review on recent progresses," Phys. Rep. 413, 319-398 (2005) and references therein.

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

J. Geist, G. Brida, and M. L. Rastello, "Prospects for improving the accuracy of silicon photodiode self-calibration with custom cryogenic photodiodes," Metrologia 40, 132-135 (2003).

[CrossRef]

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

N. P. Fox, "Primary radiometric quantities and units," Metrologia 37, 507-513 (2000).

[CrossRef]

G. Brida, M. Genovese, and C. Novero, "An application of two photon entangled states to quantum metrology," J. Mod. Opt. 47, 2099-2104 (2000).

[CrossRef]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

A. Migdall, "Correlated-photon metrology without absolute standards," Phys. Today 52, 41-46 (1999).

[CrossRef]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

D. N. Klyshko and A. V. Masalov, "Photon noise: observation, squeezing, interpretation," Phys. Usp. 38, 1203-1230 (1995).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

D. T. Smithey, M. Beck, M. Belsley, and M. G. Raymer, "Sub-shot-noise correlation of total photon number using macroscopic twin pulses of light," Phys. Rev. Lett. 69, 2650-2653 (1992).

[CrossRef]
[PubMed]

J. Mertz, A. Heidmann, and C. Fabre, "Generation of sub-Poissonian light using active control with twin beams," Phys. Rev. A 44, 3229-3238 (1991).

[CrossRef]
[PubMed]

P. R. Tapster, J. G. Rarity, and J. S. Satchell, "Use of parametric down-conversion to generate sub-Poissonian light," Phys. Rev. A 37, 2963-2967 (1988).

[CrossRef]
[PubMed]

J. H. Shapiro, G. Saplakoglu, S.-T. Ho, P. Kumar, B. E. A. Saleh, and M. C. Teich, "Theory of light detection in the presence of feedback," J. Opt. Soc. Am. B 4, 1604-1620 (1987).

[CrossRef]

D. N. Klyshko and A. N. Penin, "The prospects of quantum photometry," Sov. Phys. Usp. 30, 716-723 (1987).

[CrossRef]

A. V. Sergienko and A. N. Penin, "Absolute calibration of analog photodetectors using biphotonic fields," Sov. Tech. Phys. Lett. 12, 328-329 (1986).

T. J. Quinn and J. E. Martin, "A radiometric determination of the Stefan-Boltzmann constant and thermodynamic temperatures between −408C and +1008C," Philos. Trans. R. Soc. London 316, 85-181 (1985).

[CrossRef]

A. A. Malygin, A. N. Penin, and A. V. Sergienko, "Absolute calibration of the sensitivity of photodetectors using a two-photon field," Sov. Phys. JETP Lett. 33, 477-480 (1981).

K. Soda, I. Nishio, and A. Wada, "Analysis of noises in photocurrent time-correlation spectroscopy of scattered light," J. Appl. Phys. 47, 729-735 (1976).

[CrossRef]

D. C. Burnham and D. L. Weinberg, "Observation of simultaneity in parametric production of optical photon pairs," Phys. Rev. Lett. 25, 84-87 (1970).

[CrossRef]

B. Y. Zel'dovich and D. N. Klyshko, "Statistics of field in parametric luminescence," Sov. Phys. JETP Lett. 9, 40-44 (1969).

R. G. McIntyre, "Multiplication noise in uniform avalanche diodes," IEEE Trans. Electron Devices ED-13, 164-168 (1966).

[CrossRef]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

G. Auletta, Foundations and Interpretation of Quantum Mechanics (World Scientific, 2000) and references therein.

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

H. A. Bachor, A Guide to Experimental Quantum Optics (Wiley-VCH, 1998).

D. T. Smithey, M. Beck, M. Belsley, and M. G. Raymer, "Sub-shot-noise correlation of total photon number using macroscopic twin pulses of light," Phys. Rev. Lett. 69, 2650-2653 (1992).

[CrossRef]
[PubMed]

D. T. Smithey, M. Beck, M. Belsley, and M. G. Raymer, "Sub-shot-noise correlation of total photon number using macroscopic twin pulses of light," Phys. Rev. Lett. 69, 2650-2653 (1992).

[CrossRef]
[PubMed]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

[CrossRef]

G. Brida, M. Genovese, and M. Gramegna, "Twin-photon techniques for photo-detector calibration," Laser Phys. Lett. 3, 115-123 (2006).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

J. Geist, G. Brida, and M. L. Rastello, "Prospects for improving the accuracy of silicon photodiode self-calibration with custom cryogenic photodiodes," Metrologia 40, 132-135 (2003).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

G. Brida, M. Genovese, and C. Novero, "An application of two photon entangled states to quantum metrology," J. Mod. Opt. 47, 2099-2104 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

D. C. Burnham and D. L. Weinberg, "Observation of simultaneity in parametric production of optical photon pairs," Phys. Rev. Lett. 25, 84-87 (1970).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

See, for example, M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information (Cambridge U. Press, 2000).

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

J. Mertz, A. Heidmann, and C. Fabre, "Generation of sub-Poissonian light using active control with twin beams," Phys. Rev. A 44, 3229-3238 (1991).

[CrossRef]
[PubMed]

N. P. Fox, "Primary radiometric quantities and units," Metrologia 37, 507-513 (2000).

[CrossRef]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

[CrossRef]

G. Brida, M. Genovese, and M. Gramegna, "Twin-photon techniques for photo-detector calibration," Laser Phys. Lett. 3, 115-123 (2006).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

M. Genovese, "Research on hidden variable theories: a review on recent progresses," Phys. Rep. 413, 319-398 (2005) and references therein.

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

G. Brida, M. Genovese, and C. Novero, "An application of two photon entangled states to quantum metrology," J. Mod. Opt. 47, 2099-2104 (2000).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

G. Brida, M. Genovese, and M. Gramegna, "Twin-photon techniques for photo-detector calibration," Laser Phys. Lett. 3, 115-123 (2006).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

J. Mertz, A. Heidmann, and C. Fabre, "Generation of sub-Poissonian light using active control with twin beams," Phys. Rev. A 44, 3229-3238 (1991).

[CrossRef]
[PubMed]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

D. N. Klyshko and A. V. Masalov, "Photon noise: observation, squeezing, interpretation," Phys. Usp. 38, 1203-1230 (1995).

[CrossRef]

D. N. Klyshko and A. N. Penin, "The prospects of quantum photometry," Sov. Phys. Usp. 30, 716-723 (1987).

[CrossRef]

D. N. Klyshko, "Use of two-photon light for absolute calibration of photoelectric detectors," Sov. J. Quantum Electron. 10, 1112-1116 (1980).

[CrossRef]

B. Y. Zel'dovich and D. N. Klyshko, "Statistics of field in parametric luminescence," Sov. Phys. JETP Lett. 9, 40-44 (1969).

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

[CrossRef]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

A. A. Malygin, A. N. Penin, and A. V. Sergienko, "Absolute calibration of the sensitivity of photodetectors using a two-photon field," Sov. Phys. JETP Lett. 33, 477-480 (1981).

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge U. Press, 1985).

T. J. Quinn and J. E. Martin, "A radiometric determination of the Stefan-Boltzmann constant and thermodynamic temperatures between −408C and +1008C," Philos. Trans. R. Soc. London 316, 85-181 (1985).

[CrossRef]

D. N. Klyshko and A. V. Masalov, "Photon noise: observation, squeezing, interpretation," Phys. Usp. 38, 1203-1230 (1995).

[CrossRef]

R. G. McIntyre, "Multiplication noise in uniform avalanche diodes," IEEE Trans. Electron Devices ED-13, 164-168 (1966).

[CrossRef]

J. Mertz, A. Heidmann, and C. Fabre, "Generation of sub-Poissonian light using active control with twin beams," Phys. Rev. A 44, 3229-3238 (1991).

[CrossRef]
[PubMed]

A. Migdall, "Correlated-photon metrology without absolute standards," Phys. Today 52, 41-46 (1999).

[CrossRef]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

See, for example, M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information (Cambridge U. Press, 2000).

K. Soda, I. Nishio, and A. Wada, "Analysis of noises in photocurrent time-correlation spectroscopy of scattered light," J. Appl. Phys. 47, 729-735 (1976).

[CrossRef]

G. Brida, M. Genovese, and C. Novero, "An application of two photon entangled states to quantum metrology," J. Mod. Opt. 47, 2099-2104 (2000).

[CrossRef]

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[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

D. N. Klyshko and A. N. Penin, "The prospects of quantum photometry," Sov. Phys. Usp. 30, 716-723 (1987).

[CrossRef]

A. V. Sergienko and A. N. Penin, "Absolute calibration of analog photodetectors using biphotonic fields," Sov. Tech. Phys. Lett. 12, 328-329 (1986).

A. A. Malygin, A. N. Penin, and A. V. Sergienko, "Absolute calibration of the sensitivity of photodetectors using a two-photon field," Sov. Phys. JETP Lett. 33, 477-480 (1981).

T. J. Quinn and J. E. Martin, "A radiometric determination of the Stefan-Boltzmann constant and thermodynamic temperatures between −408C and +1008C," Philos. Trans. R. Soc. London 316, 85-181 (1985).

[CrossRef]

P. R. Tapster, J. G. Rarity, and J. S. Satchell, "Use of parametric down-conversion to generate sub-Poissonian light," Phys. Rev. A 37, 2963-2967 (1988).

[CrossRef]
[PubMed]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

J. Geist, G. Brida, and M. L. Rastello, "Prospects for improving the accuracy of silicon photodiode self-calibration with custom cryogenic photodiodes," Metrologia 40, 132-135 (2003).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

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[CrossRef]
[PubMed]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

P. R. Tapster, J. G. Rarity, and J. S. Satchell, "Use of parametric down-conversion to generate sub-Poissonian light," Phys. Rev. A 37, 2963-2967 (1988).

[CrossRef]
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E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

A. V. Sergienko and A. N. Penin, "Absolute calibration of analog photodetectors using biphotonic fields," Sov. Tech. Phys. Lett. 12, 328-329 (1986).

A. A. Malygin, A. N. Penin, and A. V. Sergienko, "Absolute calibration of the sensitivity of photodetectors using a two-photon field," Sov. Phys. JETP Lett. 33, 477-480 (1981).

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

D. T. Smithey, M. Beck, M. Belsley, and M. G. Raymer, "Sub-shot-noise correlation of total photon number using macroscopic twin pulses of light," Phys. Rev. Lett. 69, 2650-2653 (1992).

[CrossRef]
[PubMed]

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[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

P. R. Tapster, J. G. Rarity, and J. S. Satchell, "Use of parametric down-conversion to generate sub-Poissonian light," Phys. Rev. A 37, 2963-2967 (1988).

[CrossRef]
[PubMed]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
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K. Soda, I. Nishio, and A. Wada, "Analysis of noises in photocurrent time-correlation spectroscopy of scattered light," J. Appl. Phys. 47, 729-735 (1976).

[CrossRef]

D. C. Burnham and D. L. Weinberg, "Observation of simultaneity in parametric production of optical photon pairs," Phys. Rev. Lett. 25, 84-87 (1970).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

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T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

B. Y. Zel'dovich and D. N. Klyshko, "Statistics of field in parametric luminescence," Sov. Phys. JETP Lett. 9, 40-44 (1969).

E. Brambilla, A. Gatti, L. A. Lugiato, and M. I. Kolobov, "Quantum structures in traveling-wave spontaneous parametric down-conversion," Eur. Phys. J. D 15, 127-135 (2001).

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[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Absolute quantum efficiency measurements by means of conditioned polarization rotation," IEEE Trans. Instrum. Meas. 54, 898-900 (2005).

[CrossRef]

K. Soda, I. Nishio, and A. Wada, "Analysis of noises in photocurrent time-correlation spectroscopy of scattered light," J. Appl. Phys. 47, 729-735 (1976).

[CrossRef]

G. Brida, M. Genovese, and C. Novero, "An application of two photon entangled states to quantum metrology," J. Mod. Opt. 47, 2099-2104 (2000).

[CrossRef]

G. Brida, M. Chekhova, M. Genovese, M. Gramegna, L. Krivitsky, and M. L. Rastello, "Single-photon detector calibration by means of conditional polarization rotation," J. Opt. Soc. Am. B 22, 488-492 (2005).

[CrossRef]

J. H. Shapiro, G. Saplakoglu, S.-T. Ho, P. Kumar, B. E. A. Saleh, and M. C. Teich, "Theory of light detection in the presence of feedback," J. Opt. Soc. Am. B 4, 1604-1620 (1987).

[CrossRef]

G. Brida, M. Genovese, and M. Gramegna, "Twin-photon techniques for photo-detector calibration," Laser Phys. Lett. 3, 115-123 (2006).

[CrossRef]

N. P. Fox, "Primary radiometric quantities and units," Metrologia 37, 507-513 (2000).

[CrossRef]

J. Geist, G. Brida, and M. L. Rastello, "Prospects for improving the accuracy of silicon photodiode self-calibration with custom cryogenic photodiodes," Metrologia 40, 132-135 (2003).

[CrossRef]

E. Dauler, A. Migdall, N. Boeuf, R. U. Dalta, A. Mullerand, and A. Sergienko, "Measuring absolute infrared spectral radiance with correlated photons: new arrangement for improved uncertainty and extended IR range," Metrologia 35, 295-300 (1998).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Towards an uncertainty budget in quantum-efficiency measurements with parametric fluorescence," Metrologia 37, 629-632 (2000).

[CrossRef]

G. Brida, S. Castelletto, I. P. Degiovanni, C. Novero, and M. L. Rastello, "Quantum efficiency and dead time of single-photon counting photodiodes: a comparison between two measurement techniques," Metrologia 37, 625-628 (2000).

[CrossRef]

F. Grosshans, G. Van Assche, J. Wenger, R. Brouri, N. J. Cerf, and P. Grangier, "Quantum key distribution using Gaussian-modulated coherent states," Nature 421, 238-241 (2003).

[CrossRef]
[PubMed]

V. M. Ginzburg, N. G. Keratishvili, E. L. Korzhenevich, G. V. Lunev, A. N. Penin, and V. I. Sapritsky, "Absolute meter of photodetector quantum efficiency based on the parametric down-conversion effect," Opt. Eng. 32, 2911-2916 (1993).

[CrossRef]

T. J. Quinn and J. E. Martin, "A radiometric determination of the Stefan-Boltzmann constant and thermodynamic temperatures between −408C and +1008C," Philos. Trans. R. Soc. London 316, 85-181 (1985).

[CrossRef]

M. Genovese, "Research on hidden variable theories: a review on recent progresses," Phys. Rep. 413, 319-398 (2005) and references therein.

[CrossRef]

T. Hirano, H. Yamanaka, M. Ashikaga, T. Konishi, and R. Namiki, "Quantum cryptography using pulsed homodyne detection," Phys. Rev. A 68, 42331-42337 (2003).

[CrossRef]

G. Brida, M. V. Chekhova, M. Genovese, M. Gramegna, L. A. Krivitsky, and S. P. Kulik, "Conditioned unitary transformation on biphotons," Phys. Rev. A 70, 032332 (2004).

[CrossRef]

P. R. Tapster, J. G. Rarity, and J. S. Satchell, "Use of parametric down-conversion to generate sub-Poissonian light," Phys. Rev. A 37, 2963-2967 (1988).

[CrossRef]
[PubMed]

E. Brambilla, A. Gatti, M. Bache, and L. A. Lugiato, "Simultaneous near-field and far-field spatial quantum correlations in the high-gain regime of parametric down-conversion," Phys. Rev. A 69, 023802 (2004).

[CrossRef]

A. V. Burlakov, M. V. Chekhova, D. N. Klyshko, S. P. Kulik, A. N. Penin, Y. H. Shih, and D. V. Strekalov, "Interference effects in spontaneous two-photon parametric scattering from two macroscopic regions," Phys. Rev. A 56, 3214-3225 (1997).

[CrossRef]

J. Mertz, A. Heidmann, and C. Fabre, "Generation of sub-Poissonian light using active control with twin beams," Phys. Rev. A 44, 3229-3238 (1991).

[CrossRef]
[PubMed]

D. T. Smithey, M. Beck, M. Belsley, and M. G. Raymer, "Sub-shot-noise correlation of total photon number using macroscopic twin pulses of light," Phys. Rev. Lett. 69, 2650-2653 (1992).

[CrossRef]
[PubMed]

O. Jedrkiewicz, Y.-K Jiang, E. Brambilla, A. Gatti, M. Bache, L. A. Lugiato, and P. Di Trapani, "Detection of sub-shot-noise spatial correlation in high-gain parametric down conversion," Phys. Rev. Lett. 93, 0243601 (2004).

[CrossRef]

D. C. Burnham and D. L. Weinberg, "Observation of simultaneity in parametric production of optical photon pairs," Phys. Rev. Lett. 25, 84-87 (1970).

[CrossRef]

A. Migdall, "Correlated-photon metrology without absolute standards," Phys. Today 52, 41-46 (1999).

[CrossRef]

D. N. Klyshko and A. V. Masalov, "Photon noise: observation, squeezing, interpretation," Phys. Usp. 38, 1203-1230 (1995).

[CrossRef]

See, for a general review, N. Gisin, G. Ribordy, W. Tittel, and H. Zbinden, "Quantum cryptography," Rev. Mod. Phys. 74, 145-195 (2000) and references therein.

[CrossRef]

D. N. Klyshko, "Use of two-photon light for absolute calibration of photoelectric detectors," Sov. J. Quantum Electron. 10, 1112-1116 (1980).

[CrossRef]

A. A. Malygin, A. N. Penin, and A. V. Sergienko, "Absolute calibration of the sensitivity of photodetectors using a two-photon field," Sov. Phys. JETP Lett. 33, 477-480 (1981).

B. Y. Zel'dovich and D. N. Klyshko, "Statistics of field in parametric luminescence," Sov. Phys. JETP Lett. 9, 40-44 (1969).

D. N. Klyshko and A. N. Penin, "The prospects of quantum photometry," Sov. Phys. Usp. 30, 716-723 (1987).

[CrossRef]

A. V. Sergienko and A. N. Penin, "Absolute calibration of analog photodetectors using biphotonic fields," Sov. Tech. Phys. Lett. 12, 328-329 (1986).

Indeed, in the calculation of the cross-correlation function it is sufficient to assume that only one of the two areas, for instance, R2, obeys this restriction. We also performed the calculation under the opposite condition, but the results do not present any particular interest here.

The condition is fulfilled if the electronics is the same for the two detectors and has a passband much smaller than the band of the detectors.

See, for example, M. A. Nielsen and I. L. Chuang, Quantum Computation and Quantum Information (Cambridge U. Press, 2000).

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge U. Press, 1985).

H. A. Bachor, A Guide to Experimental Quantum Optics (Wiley-VCH, 1998).

G. Auletta, Foundations and Interpretation of Quantum Mechanics (World Scientific, 2000) and references therein.

[CrossRef]