Disclosed are dielectric cavity arrays with cavities formed by pairs of dielectric tips, wherein the cavities have low mode volume (e.g., 7*10.sup.−5λ.sup.3, where X is the resonance wavelength of the cavity array), and large quality factor Q (e.g., 10.sup.6 or more). Applications for such dielectric cavity arrays include, but are not limited to, Raman spectroscopy, second harmonic generation, optical signal detection, microwave-to-optical transduction, and as light emitting devices.

A method for enhancement of spontaneous Raman scattering (SRS) from gases comprising a multimode blue laser diode which receives feedback from a near concentric bidirectional multipass cavity in such a way as to generate a circulating power of order 100 W for a sample volume of 10 mm.sup.3. The feedback, provided via a volume Bragg grating, reduces the laser bandwidth to 4 cm.sup.−1. Spectra of spontaneous Raman scattering from ambient atmospheric air, detected collinearly with the pump, were recorded with a limit of detection below 1 part-per-million.

An analysis device and an analysis apparatus for identification of analytes in fluids applying the SERS effect which provides a safe way to perform analysis, avoiding an accidental cross-contamination without the use of disinfectant products; the analysis device comprising a casing enclosing a sample region for receiving a fluid sample, and a nanoparticle region for storing at least a nanoparticle fluid; the sample region and the nanoparticle region being in fluid communication each other through a passage; driving means in fluid communication with the passage; a mixing region in fluid communication with the passage; and the casing being adapted to allow an incident monochromatic light from an external source to strike on the mixing region, and a reflected light from the mixing region to leave the casing.

A stimulated Raman scattering (SRS) spectrometer for real-time, high-resolution molecular analysis of gases is based on two hollow-core fibres illuminated by a single high-power, short-pulse laser pump. The first fibre is prefilled with high-concentration target gases. Interaction of each target gas inside the first fibre, with the laser pump, generates Raman signals corresponding to the target gases. The combined beam of the Raman signals and the pump laser beam is directed into the second fibre containing the measured target gases. Interaction of each target gas with the combined beam generates the Stimulated Raman Growth (SRG), i.e., amplification of the Raman signal, which is proportional to the corresponding target gas concentration. A receiver subsystem receives the beam from the second fibre, spectrally separates it to wavelengths corresponding to each target gas, extracts the SRG value corresponding to each target gas and calculates the concentration of each target gas.

A method for detecting the quality of cell culture fluid based on Raman spectral measurement. The method comprises the following steps: collecting cell culture fluid; collecting, processing and analyzing a Raman spectral signal; measuring an original Raman spectral signal of a metabolite in the cell culture fluid using a Raman spectra technique; determining whether the original Raman spectral signal is qualified, and carrying out data signal processing on the qualified original Raman spectral signal to obtain analyzable signals; and then carrying out difference statistical analysis on the analyzable signals to obtain difference signals; carrying out modeling using the difference signals; classifying the difference signals using a support vector machine; and distinguishing the spectral signals of normal and abnormal cell culture fluid to obtain a quality result of the cell culture fluid. Difference signals in cell culture fluid are detected by means of Raman spectra to detect the quality of the cell culture fluid, thereby achieving the purpose of non-invasive evaluation of a cell growth state; and the method is convenient, effective and low-cost, and can achieve large-scale industrialization and streamlining.

Apparatuses, systems, and methods for Raman spectroscopy are described. In certain implementations, a spectrometer is provided. The spectrometer may include a plurality of optical elements, comprising an entrance aperture, a collimating element, a volume phase holographic grating, a focusing element, and a detector array. The plurality of optical elements are configured to transfer the light beam from the entrance aperture to the detector array with a high transfer efficiency over a preselected spectral band.

A flow cell system includes a vessel and a fluid located in the vessel. A fluid surface of the fluid can be vented to a first gas pressure. The fluid surface can have a first cross-sectional area. The flow cell system includes a conduit in fluid communication with the vessel and positioned downstream of the vessel. The conduit can have a region that includes one or more orifices and has a second cross-sectional area. The second cross-sectional area can be less than the first cross-sectional area. The one or more orifices can be vented to a second gas pressure. The second gas pressure can be equal to or greater than the first gas pressure. Methods for analyzing a process fluid can include characterizing the fluid in the conduit.

A method and a system for identifying the quality of a liquid pharmaceutical product as described. The method comprises providing a liquid pharmaceutical product in a sealed container and arranging the sealed container such that the liquid pharmaceutical product forms a sample layer in a first portion of the sealed container. The method further comprises directing a light beam through the sample layer and measuring a spectrum of the sample layer. The spectrum is chosen from the group of a NIR spectrum or a Raman spectrum. The method further comprises identifying the quality of the liquid pharmaceutical product by comparing the spectrum with a reference spectrum corresponding to an expected pharmaceutical product.

A test cell for operando testing comprises: a housing assembly defining at least a portion of an inner chamber; a window coupled to said housing assembly and defining another portion of the inner chamber; and at least one port for accommodating an electrode and/or conductive wire in communication with the inner chamber. The inner chamber is configured for receiving one or more samples undergoing a chemical and/or electrochemical reaction therein. The port is sealable to hermetically seal the inner chamber.

Described herein are devices and methods of use thereof, the devices comprising: a sample conduit providing a path for fluid flow extending from a sample inlet to a sample outlet; a thermal housing enclosing the sample conduit, the thermal housing comprising a plurality of measurement regions; and a motorized stage translatable along the thermal housing so as to align a detector with one or more of the plurality of measurement regions. The devices can continuously flow a fluid precursor sample from the sample inlet to the sample outlet, the fluid precursor sample comprising a first precursor and a second precursor, such that the first precursor reacts with the second precursor as the fluid precursor sample continuously flows from the sample inlet to the sample outlet to form the sample before reaching the sample outlet, wherein the sample comprises a plurality of particles or an organic molecule.