Rotational diffusion measurements using polarization-dependent fluorescence correlation spectroscopy based on...

Area of Science:

• Photonics
• Spectroscopy
• Materials Science

Background:

• Conventional polarization-dependent fluorescence correlation spectroscopy (pol-FCS) relies on dual-channel systems to mitigate after-pulse noise.
• This dual-channel approach complicates optical setups and can limit signal quality.

Purpose of the Study:

• To develop a simplified pol-FCS method using a single-channel detector.
• To demonstrate the feasibility of using a visible-wavelength superconductive nanowire single-photon detector for pol-FCS.
• To improve signal-to-noise ratios in pol-FCS measurements.

Main Methods:

• Implementation of single-channel pol-FCS (SC-pol-FCS) utilizing a superconductive nanowire single-photon detector.
• Characterization of the detector's performance, specifically its freedom from after-pulse noise.
• Comparison of SC-pol-FCS with conventional dual-channel pol-FCS (DC-pol-FCS) in terms of optical setup and signal quality.

Main Results:

• Successfully realized pol-FCS using a single-channel system (SC-pol-FCS).
• The superconductive nanowire single-photon detector eliminated the need for dual channels due to its lack of after-pulse noise.
• Achieved higher signal-to-noise ratios compared to conventional DC-pol-FCS systems.
• Demonstrated simpler optical alignment for the SC-pol-FCS system.

Conclusions:

• SC-pol-FCS offers a simplified and more efficient approach to pol-FCS measurements.
• This technique has the potential to enhance the study of rotational diffusion.
• The use of after-pulse noise-free single-photon detectors is key to advancing pol-FCS methodologies.