Further data are available from the corresponding author upon reasonable request. 11) and comparative cell images with and without quantum enhancement (Supplementary Fig. 10) measurements of cell photodamage (Supplementary Fig. 9) the photocurrent power spectral density used to determine the concentration sensitivity when probing the CH aromatic stretch band in polystyrene (Supplementary Fig. 7) experimental measurements of the squeezed variance and classical deamplification of the Stokes field as a function of the optical parametric amplifier pump power (Supplementary Fig. 6) the raw measured power spectral densities of detector electronic noise, shot-noise and squeezing (Supplementary Fig. 3– 5) example power spectral densities of the stimulated Raman signal-to-noise ratio with and without squeezing (Supplementary Fig. This includes data quantifying the detector design and performance (Supplementary Figs.
The data that support the findings of this study are included in the Supplementary Information. By showing that the photodamage limit can be overcome, our work will enable order-of-magnitude improvements in the signal-to-noise ratio and the imaging speed. Coherent Raman microscopes allow highly selective biomolecular fingerprinting in unlabelled specimens 6, 7, but photodamage is a major roadblock for many applications 8, 9. This enables the observation of biological structures that would not otherwise be resolved. The correlations allow imaging of molecular bonds within a cell with a 35 per cent improved signal-to-noise ratio compared with conventional microscopy, corresponding to a 14 per cent improvement in concentration sensitivity. Our microscope is a coherent Raman microscope that offers subwavelength resolution and incorporates bright quantum correlated illumination. Here we experimentally show that quantum correlations allow a signal-to-noise ratio beyond the photodamage limit of conventional microscopy. Theory predicts that biological imaging may be improved without increasing light intensity by using quantum photon correlations 1, 5. Although the long-established solution to this problem is to increase the intensity of the illumination light, this is not always possible when investigating living systems, because bright lasers can severely disturb biological processes 2, 3, 4. Randomness in the times that photons are detected introduces shot noise, which fundamentally constrains sensitivity, resolution and speed 1.
The use of the anti‐Stokes side is an advantage, as demonstrated by R(v̄) spectra of an aqueous solution of L‐aspartic acid.The performance of light microscopes is limited by the stochastic nature of light, which exists in discrete packets of energy known as photons. This procedure is of special importance for aqueous solutions of biologically interesting molecules. The background correction for Raman spectra in the R(v̄) representation is discussed. The same method was used for liquid water at temperatures ranging from the freezing point to 40☌. The results allow a distinction between the effects of stray light and fluorescence in the spectra. Results for a pure and an impure sample of fluorobenzene were compared. The spectra are given in the R(v̄) representation. Low‐frequency Raman spectra of liquids on both Stokes and anti‐Stokes sides were investigated. Anti‐Stokes low‐frequency Raman spectra of liquids Anti‐Stokes low‐frequency Raman spectra of liquids