Nonlinear Correlation Spectroscopy (NLCS)

Abstract

We present a novel concept for optical spectroscopy called nonlinear correlation spectroscopy (NLCS). NLCS analyses coherent field fluctuations of the second and third harmonic light generated by diffusing nanoparticles. Particles based on noncentrosymmetric nonlinear materials such as KNbO(3) show a strong second as well as third harmonic response. The method and the theory are introduced and experimental NLCS results in fetal calf serum are presented showing the promising selectivity of this technique for measurement in complex biological environments.

Cellular uptake and biocompatibility of bismuth ferrite harmonic advanced nanoparticles

“…flow cytometry. 38 Therefore, the aim of this work was, for the first time, to present the behaviour of these particles in their uncoated or PEGylated form, focusing on relevant exposure time point relevant to diagnostic applications. Such assessment comes timely after the first demonstrations of their interest for bio-imaging and selective photointeraction, as, due to their novelty, there is still a knowledge gap that requires the scientific community attention towards the investigation of their biological effect.…”

Harmonic nanoparticles: noncentrosymmetric metal oxides for nonlinear optics

“…This finding can be easily exploited in combination with new infrared ultrafast sources, enabling the detection of second and TH in the visible and UV-visible range, respectively. The approach can greatly benefit signal selectivity for bioimaging and detection [61,70] but also opens previously unforeseen applications in other fields [68]. …”

Single-cell screening and quantification of transcripts in cancer tissues by second-harmonic generation microscopy

“…22 SHG nanocrystals, such as barium titanium oxide (BaTiO 3 , BTO), lithium niobate (LiNbO 3 ), potassium titanyl phosphate (KTiOPO 4 , KTP), and lithium triborate (LiB 3 O 5 , LBO), have been used to detect single molecules with a regular and holographic second-harmonic imaging microscopy (SHIM) [19][20][21][22]24 and correlation spectroscopy. 25,26 Compared with fluorescence probes, the SHG emission is free from saturation and bleaching, and has an intense and stable output with a narrow spectral window, where the environmental autofluorescence can be minimized to be background-free for analysis of optically challenging samples such as tissues.…”