Designing high-power, octave spanning entangled photon sources for quantum spectroscopy

Area of Science:

• Quantum optics
• Spectroscopy
• Materials science

Background:

• Entangled photon spectroscopy offers enhanced resolution and new measurement capabilities.
• High-flux entangled photon sources are essential for practical applications.
• Existing sources often lack the necessary flux for widespread adoption.

Purpose of the Study:

• To develop a high-flux entangled photon source.
• To demonstrate its utility for entangled photon spectroscopy.
• To enable broader applications in chemical, biological, and materials research.

Main Methods:

• Utilized a periodically poled, chirped lithium tantalate platform.
• Employed a near-watt level diode laser for pumping.
• Observed spectral-temporal photon correlations using a Michelson-type interferometer and broadband Hong-Ou-Mandel interference.

Main Results:

• Achieved entangled photon pair generation with ~10^-7 efficiency, resulting in near μW-level flux.
• Demonstrated maintenance of the single photon per mode limit over octave-spanning bandwidths.
• Measured coherence times of 245 fs (10 nm bandwidth, collinear) and 62 fs (125 nm bandwidth, non-collinear).

Conclusions:

• The developed platform provides a high-flux source of entangled photons.
• This technology advances the practical implementation of entangled photon spectroscopy.
• Numerical methods allow for tailoring source properties like wavelength and bandwidth for UV-Vis applications.