Femtosecond fluorescence conical optical parametric amplification spectroscopy

Ennan Cui; Heyuan Liu; Zhuan Wang; Hailong Chen; Yu-Xiang Weng

doi:10.1063/5.0197254

Femtosecond fluorescence conical optical parametric amplification spectroscopy

Rev Sci Instrum. 2024 Mar 1;95(3):033008. doi: 10.1063/5.0197254.

Authors

Ennan Cui^{1

2}, Heyuan Liu^{1

2}, Zhuan Wang¹, Hailong Chen^{1

2

3}, Yu-Xiang Weng^{1

2

3}

Affiliations

¹ The Laboratory of Soft Matter Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² School of Physical Science, University of the Chinese Academy of Sciences, Beijing 100049, China.
³ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.

PMID: 38517256
DOI: 10.1063/5.0197254

Abstract

Parametric superfluorescence (PSF), which originated from the optical amplification of vacuum quantum noise, is the primary noise source of femtosecond fluorescence non-collinear optical parametric amplification spectroscopy (FNOPAS). It severely affects the detection limit of FNOPAS to collect the femtosecond time-resolved spectra of extremely weak fluorescence. Here, we report the development of femtosecond fluorescence conical optical parametric amplification spectroscopy (FCOPAS), aimed at effectively suppressing the noise fluctuation from the PSF background. In contrast to traditional FNOPAS configurations utilizing lateral fluorescence collection and dot-like parametric amplification, FCOPAS employs an innovative conical fluorescence collection and ring-like amplification setup. This design enables effective cancellation of noise fluctuation across the entire PSF ring, resulting in an approximate order of magnitude reduction in PSF noise compared to prior FNOPAS outcomes. This advancement enables the resolution of transient fluorescence spectra of 4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) dye molecules in ethanol, even at an optically dilute concentration of 10-6 mol/l, with significantly enhanced signal-to-noise ratios. This improvement will be significant for extremely weak fluorescence detection on the femtosecond time scale.