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A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
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Enhancing Entangled Two-Photon Absorption for Picosecond Quantum Spectroscopy
Ryan K Burdick1, George C Schatz2, Theodore Goodson1
1Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States.
Journal of the American Chemical Society
|October 6, 2021
Summary
Entangled two-photon absorption (ETPA) can be enhanced using spectral-spatial coupling. This allows for more efficient nonlinear optical measurements and photochemical control at the picosecond scale.
Area of Science:
- Quantum optics
- Nonlinear spectroscopy
- Photochemistry
Background:
- Entangled two-photon absorption (ETPA) offers reduced phototoxicity due to low light intensity.
- Previous studies predicted ETPA cross-section inversely proportional to entanglement area and time (σe ∝ 1/AeTe).
- This relationship limited ETPA to femtosecond timescales, leaving picosecond applications unexplored.
Purpose of the Study:
- Investigate the role of spectral-spatial coupling in ETPA cross-section.
- Explore ETPA applications at picosecond timescales.
- Enhance ETPA efficiency by utilizing narrowband entangled photons.
Main Methods:
- Experimental measurement of ETPA cross-section for zinc tetraphenylporphyrin.
- Varying the spontaneous parametric down-conversion (SPDC) bandwidth (σf) to alter spectral-spatial coupling.
- Theoretical analysis of experimental data.
Main Results:
- Spectral-spatial coupling significantly impacts σe for entanglement times > 100 fs.
- For type-I ETPA, σe increases as SPDC bandwidth (σf) decreases, peaking at σf = 0.1 ps⁻¹ (Te = 10 ps).
- At peak, type-I ETPA cross-section is 1 order larger than fs-scale ETPA and 3 orders larger than predicted for ps-scale ETPA.
Conclusions:
- Narrowband type-I ETPA, leveraging spectral-spatial coupling, overcomes previous limitations.
- This approach enables efficient nonlinear optical signal measurement with picosecond temporal precision.
- Offers new possibilities for controlling photochemical reactions requiring ps temporal resolution.
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