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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

Justification of the effective Hamiltonian.Here we give a comparison of the population dynamics calculated according to respectively the original Hamiltonian HpJC (equation (1)) and the effective Hamiltonian Heff (equation (4)), in the presence of cavity decay. (a–d) Give the time-dependence of the occupations of the states /−0〉, /+2〉, /+1〉 and /+0〉, respectively. The original-Hamiltonian results are given by black solid lines, while the effective-Hamiltonian results are given by red dashed lines. As can be seen, HpJC and Heff give essentially indistinguishable results. The initial state is /−0〉. g = 1, κ = 0.1, Ω = 32, δcav = −34.46 and δTLS = 25.54 in equation (4). Calculational details are given in Methods. Note that it may seem very strange that the population would go spontaneously from the low energy state /−0〉 to the high energy state /+2〉. However, the extra energy is actually provided by the pumping laser. This process can be understood naturally using the dressed state picture. For an elucidating discussion on this point, we refer to ref. 37.
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f3: Justification of the effective Hamiltonian.Here we give a comparison of the population dynamics calculated according to respectively the original Hamiltonian HpJC (equation (1)) and the effective Hamiltonian Heff (equation (4)), in the presence of cavity decay. (a–d) Give the time-dependence of the occupations of the states /−0〉, /+2〉, /+1〉 and /+0〉, respectively. The original-Hamiltonian results are given by black solid lines, while the effective-Hamiltonian results are given by red dashed lines. As can be seen, HpJC and Heff give essentially indistinguishable results. The initial state is /−0〉. g = 1, κ = 0.1, Ω = 32, δcav = −34.46 and δTLS = 25.54 in equation (4). Calculational details are given in Methods. Note that it may seem very strange that the population would go spontaneously from the low energy state /−0〉 to the high energy state /+2〉. However, the extra energy is actually provided by the pumping laser. This process can be understood naturally using the dressed state picture. For an elucidating discussion on this point, we refer to ref. 37.

Mentions: Now we only need to verify that this effective Hamiltonian indeed correctly describes the dynamics of the TLS-cavity system. We show in Fig. 3 for the typical parameter combination studied in this paper a comparison between the predictions given by the original Hamiltonian (equation (1)) and those given by this effective Hamiltonian (equation (4)) in the presence of cavity decay. In the figure we plot the evolutions of the occupation-probabilities for four states: /+0〉, /+1〉, /+2〉 and /−0〉. As can be seen, for all the four states the two curves to be compared are essentially indistinguishable. Thus the effective Hamiltonian describes the system dynamics correctly. To sum up, the proposed strategy “” can be realized faithfully using the coherently pumped JC model to be “” by working in the strong coupling - large detuning - strong pumping regime and tuning the state /−0〉 and /+2〉 to be near degenerate. The realized scenario is depicted schematically in Fig. 4.


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

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

Justification of the effective Hamiltonian.Here we give a comparison of the population dynamics calculated according to respectively the original Hamiltonian HpJC (equation (1)) and the effective Hamiltonian Heff (equation (4)), in the presence of cavity decay. (a–d) Give the time-dependence of the occupations of the states /−0〉, /+2〉, /+1〉 and /+0〉, respectively. The original-Hamiltonian results are given by black solid lines, while the effective-Hamiltonian results are given by red dashed lines. As can be seen, HpJC and Heff give essentially indistinguishable results. The initial state is /−0〉. g = 1, κ = 0.1, Ω = 32, δcav = −34.46 and δTLS = 25.54 in equation (4). Calculational details are given in Methods. Note that it may seem very strange that the population would go spontaneously from the low energy state /−0〉 to the high energy state /+2〉. However, the extra energy is actually provided by the pumping laser. This process can be understood naturally using the dressed state picture. For an elucidating discussion on this point, we refer to ref. 37.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Justification of the effective Hamiltonian.Here we give a comparison of the population dynamics calculated according to respectively the original Hamiltonian HpJC (equation (1)) and the effective Hamiltonian Heff (equation (4)), in the presence of cavity decay. (a–d) Give the time-dependence of the occupations of the states /−0〉, /+2〉, /+1〉 and /+0〉, respectively. The original-Hamiltonian results are given by black solid lines, while the effective-Hamiltonian results are given by red dashed lines. As can be seen, HpJC and Heff give essentially indistinguishable results. The initial state is /−0〉. g = 1, κ = 0.1, Ω = 32, δcav = −34.46 and δTLS = 25.54 in equation (4). Calculational details are given in Methods. Note that it may seem very strange that the population would go spontaneously from the low energy state /−0〉 to the high energy state /+2〉. However, the extra energy is actually provided by the pumping laser. This process can be understood naturally using the dressed state picture. For an elucidating discussion on this point, we refer to ref. 37.
Mentions: Now we only need to verify that this effective Hamiltonian indeed correctly describes the dynamics of the TLS-cavity system. We show in Fig. 3 for the typical parameter combination studied in this paper a comparison between the predictions given by the original Hamiltonian (equation (1)) and those given by this effective Hamiltonian (equation (4)) in the presence of cavity decay. In the figure we plot the evolutions of the occupation-probabilities for four states: /+0〉, /+1〉, /+2〉 and /−0〉. As can be seen, for all the four states the two curves to be compared are essentially indistinguishable. Thus the effective Hamiltonian describes the system dynamics correctly. To sum up, the proposed strategy “” can be realized faithfully using the coherently pumped JC model to be “” by working in the strong coupling - large detuning - strong pumping regime and tuning the state /−0〉 and /+2〉 to be near degenerate. The realized scenario is depicted schematically in Fig. 4.

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