λ = wavelength of the laser used	532 nm
NA = numerical aperture	0.90
ρ = density of analyte molecule	R6G: 1.26 g/cm3	4-MBA: 1.49 g/cm3
Molecular weight	R6G: 479 g/mole	4-MBA: 154 g/mole
Area of the sample	9 cm2
Laser spot diameter ${\omega }_0=\raisebox{1ex}{$1.22\lambda $}\!\left/ \!\raisebox{-1ex}{$NA$}\right.$	7.21 × 10−5 cm
Laser focal depth $z_0=\left(\raisebox{1ex}{$2\pi $}\!\left/ \!\raisebox{-1ex}{$\lambda $}\right.\right){\omega }_0^2$	6.14 × 10−4 cm
Laser focal volume $\mathsf{\tau }={\left(\raisebox{1ex}{$\pi $}\!\left/ \!\raisebox{-1ex}{$2$}\right.\right)}^{\raisebox{1ex}{$3$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}{\omega }_0^2\left(z_0\right)$	6.3× 10−12 cm3