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A simple and general strategy for generating frequency-anticorrelated photon pairs.

Zhang X, Xu C, Ren Z - Sci Rep (2016)

Bottom Line: To reduce the required flux, a promising solution is to use highly frequency-anticorrelated photon pairs, which are known to induce two-photon transitions much more efficiently.It is shown quantitatively that this strategy can generate highly frequency-anticorrelated photon pairs which can dramatically enhance two-photon excitation efficiency.We believe the proposed strategy can guide new designs for generating frequency-anticorrelated photon pairs.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210008, China.

ABSTRACT
Currently, two-photon excitation microscopy is the method of choice for imaging living cells within thick specimen. A remaining problem for this technique is the damage caused by the high photon flux in the excitation region. To reduce the required flux, a promising solution is to use highly frequency-anticorrelated photon pairs, which are known to induce two-photon transitions much more efficiently. It is still an open question what the best scheme is for generating such photon pairs. Here we propose one simple general strategy for this task. As an example, we show explicitly that this general strategy can be realized faithfully within the widely applicable coherently pumped Jaynes-Cummings model. It is shown quantitatively that this strategy can generate highly frequency-anticorrelated photon pairs which can dramatically enhance two-photon excitation efficiency. We believe the proposed strategy can guide new designs for generating frequency-anticorrelated photon pairs.

No MeSH data available.


Related in: MedlinePlus

Pronounced frequency anticorrelation of the emitted photon pair.(a) The probability density (arbitrary units) for one photon to have frequency δω and the other to have frequency δv, for the photon pair generated using the coherently pumped JC model (equation (6)). Both axis are measured in units of the cavity decay rate κ. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a defining feature for frequency anticorrelation. (b) Probability distribution (arbitrary units) of the sum frequency D(δω + δv) (solid) compared with that of the frequency of either photon regardless of the frequency of the other photon S(δω) (dashed), for the same photon pair as in (a). The heights of the two distributions are normalized to be the same at the center. The horizontal axis give the frequencies in units of the cavity decay rate κ. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The photon pair is thus by definition highly frequency-anticorrelated. The parameters used are the same as in Fig. 3.
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f5: Pronounced frequency anticorrelation of the emitted photon pair.(a) The probability density (arbitrary units) for one photon to have frequency δω and the other to have frequency δv, for the photon pair generated using the coherently pumped JC model (equation (6)). Both axis are measured in units of the cavity decay rate κ. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a defining feature for frequency anticorrelation. (b) Probability distribution (arbitrary units) of the sum frequency D(δω + δv) (solid) compared with that of the frequency of either photon regardless of the frequency of the other photon S(δω) (dashed), for the same photon pair as in (a). The heights of the two distributions are normalized to be the same at the center. The horizontal axis give the frequencies in units of the cavity decay rate κ. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The photon pair is thus by definition highly frequency-anticorrelated. The parameters used are the same as in Fig. 3.

Mentions: As can be seen from the above equation, the asymptotic wave function /ψ〉 contains only the component describing two photons occupying the extra-cavity modes. This means exactly one outgoing photon pair is generated. From the second term of the expression for Uωv, it can be seen that the photon pair has a sum-frequency width ~(κ − κ−). Since we work under the condition (), this width is essentially (cf. equation (6)). Thus as long as , the sum-frequency width shall be much smaller than the width of either photon, κ, i.e., the photon pair shall be highly frequency-anticorrelated. A popular way to visualize frequency correlations is to plot the joint frequency distribution , namely, the probability density for one photon to have frequency δω and the other to have frequency δv. This is shown in Fig. 5a for the typical parameter combination studied here. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a definitional feature of frequency anticorrelation17. More directly, to confirm the existence of frequency-anticorrelation one can compare the sum-frequency distribution with the frequency distribution of either photon . This is shown in Fig. 5b. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The generated photon pair is thus indeed highly frequency-anticorrelated.


A simple and general strategy for generating frequency-anticorrelated photon pairs.

Zhang X, Xu C, Ren Z - Sci Rep (2016)

Pronounced frequency anticorrelation of the emitted photon pair.(a) The probability density (arbitrary units) for one photon to have frequency δω and the other to have frequency δv, for the photon pair generated using the coherently pumped JC model (equation (6)). Both axis are measured in units of the cavity decay rate κ. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a defining feature for frequency anticorrelation. (b) Probability distribution (arbitrary units) of the sum frequency D(δω + δv) (solid) compared with that of the frequency of either photon regardless of the frequency of the other photon S(δω) (dashed), for the same photon pair as in (a). The heights of the two distributions are normalized to be the same at the center. The horizontal axis give the frequencies in units of the cavity decay rate κ. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The photon pair is thus by definition highly frequency-anticorrelated. The parameters used are the same as in Fig. 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834487&req=5

f5: Pronounced frequency anticorrelation of the emitted photon pair.(a) The probability density (arbitrary units) for one photon to have frequency δω and the other to have frequency δv, for the photon pair generated using the coherently pumped JC model (equation (6)). Both axis are measured in units of the cavity decay rate κ. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a defining feature for frequency anticorrelation. (b) Probability distribution (arbitrary units) of the sum frequency D(δω + δv) (solid) compared with that of the frequency of either photon regardless of the frequency of the other photon S(δω) (dashed), for the same photon pair as in (a). The heights of the two distributions are normalized to be the same at the center. The horizontal axis give the frequencies in units of the cavity decay rate κ. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The photon pair is thus by definition highly frequency-anticorrelated. The parameters used are the same as in Fig. 3.
Mentions: As can be seen from the above equation, the asymptotic wave function /ψ〉 contains only the component describing two photons occupying the extra-cavity modes. This means exactly one outgoing photon pair is generated. From the second term of the expression for Uωv, it can be seen that the photon pair has a sum-frequency width ~(κ − κ−). Since we work under the condition (), this width is essentially (cf. equation (6)). Thus as long as , the sum-frequency width shall be much smaller than the width of either photon, κ, i.e., the photon pair shall be highly frequency-anticorrelated. A popular way to visualize frequency correlations is to plot the joint frequency distribution , namely, the probability density for one photon to have frequency δω and the other to have frequency δv. This is shown in Fig. 5a for the typical parameter combination studied here. As can be seen, the probability distribution concentrates on a line described by δω + δv = constant, which is just a definitional feature of frequency anticorrelation17. More directly, to confirm the existence of frequency-anticorrelation one can compare the sum-frequency distribution with the frequency distribution of either photon . This is shown in Fig. 5b. As can be seen, the sum-frequency distribution is much narrower than the frequency distribution of either photon. The generated photon pair is thus indeed highly frequency-anticorrelated.

Bottom Line: To reduce the required flux, a promising solution is to use highly frequency-anticorrelated photon pairs, which are known to induce two-photon transitions much more efficiently.It is shown quantitatively that this strategy can generate highly frequency-anticorrelated photon pairs which can dramatically enhance two-photon excitation efficiency.We believe the proposed strategy can guide new designs for generating frequency-anticorrelated photon pairs.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Key Laboratory of Modern Acoustics, Nanjing University, Nanjing 210008, China.

ABSTRACT
Currently, two-photon excitation microscopy is the method of choice for imaging living cells within thick specimen. A remaining problem for this technique is the damage caused by the high photon flux in the excitation region. To reduce the required flux, a promising solution is to use highly frequency-anticorrelated photon pairs, which are known to induce two-photon transitions much more efficiently. It is still an open question what the best scheme is for generating such photon pairs. Here we propose one simple general strategy for this task. As an example, we show explicitly that this general strategy can be realized faithfully within the widely applicable coherently pumped Jaynes-Cummings model. It is shown quantitatively that this strategy can generate highly frequency-anticorrelated photon pairs which can dramatically enhance two-photon excitation efficiency. We believe the proposed strategy can guide new designs for generating frequency-anticorrelated photon pairs.

No MeSH data available.


Related in: MedlinePlus