Generation of broadband spontaneous parametric fluorescence using multiple bulk nonlinear crystals

Area of Science:

• Quantum Optics
• Nonlinear Optics
• Photonics

Background:

• Spontaneous parametric fluorescence is a key phenomenon in quantum optics.
• Generating broadband fluorescence is crucial for various quantum applications.
• Existing methods may have limitations in bandwidth or complexity.

Purpose of the Study:

• To propose and experimentally demonstrate a novel method for generating broadband spontaneous parametric fluorescence.
• To investigate the potential for further bandwidth enhancement by increasing the number of nonlinear crystals.
• To analyze the stability of two-photon interference using the generated fluorescence.

Main Methods:

• Utilizing a superposition of spontaneous parametric fluorescence spectra from multiple bulk nonlinear crystals (NLCs).
• Experimental demonstration using β-barium-borate (BBO) crystals in a non-collinear configuration.
• Characterizing the generated photon pairs and their coincidence counts.

Main Results:

• Achieved a typical bandwidth of 160 nm (73 THz) with two BBO crystals, and 75 nm (34 THz) with a single BBO crystal.
• Demonstrated that increasing the number of NLCs can further broaden the bandwidth, with potential for ~215 nm (100 THz) using four BBO crystals.
• Observed coincidence counts of generated photon pairs.

Conclusions:

• The proposed method offers a simple and effective way to generate broadband spontaneous parametric fluorescence.
• The scheme is easily implementable with conventional nonlinear crystals and standard equipment.
• The technique shows promise for applications requiring broad spectral bandwidths in quantum information processing and spectroscopy.