Disclosed are systems and methods of label-free detecting cellular physiological activities involving monitoring local refractive index changes associated with cellular physiological activities using a single ultracompact light emitting diode (LED) chip serving as a refractometer.

A refractive index measurement method uses an interference optical system which divides light from a light source having a plurality of discrete wavelengths into test light and reference light, causes the test light transmitted through the target to interfere with the reference light, and detect the interference light. The refractive index measurement method determines a first optical delay amount of the interference optical system so that a first and a second wavelength become adjacent to a wavelength corresponding to an extremal value of a phase of the interference light, measures phases of interference light at the first and second wavelengths at the first optical delay amount, and calculates a phase difference between a plurality of the discrete wavelengths at a predetermined optical delay amount using the first optical delay amount, the phases of the interference light at the first and second wavelengths to calculate the refractive index of the target.

A liquid chromatograph comprising a column coupled to a microring resonator array and methods of using the same are disclosed. The microring resonator array measures the bulk refractive index of the mobile phase and any sample injected onto and separated in the column. While carrying out the methods, the composition of a mobile phase passing through the chromatography column may remain substantially constant (isocratic elution) or it may vary (gradient elution). One or more microrings may comprise a covering to act as a thermal control. In addition, the sensor surface may be modified with some type of capture agent that can interact with one or more components in the sample.

The present disclosure embodies a refractometer that includes an embodied fitting to the standardized probe with the optical structure to facilitate refractometer optics to the probe tip.

A method of determining a refractive index of a material sample comprises removably mounting the material sample into a sample holder having a thermal control mechanism, a thermal expansion compensation mechanism, and a rotation mechanism; projecting a laser beam into the material sample, wherein the material sample has a predetermined orientation and temperature, wherein the material sample has parallel sides defining parallel planes for entry and exit of the laser beam into and out of the material sample; collecting a refracted laser beam from the material sample, and determining the refractive index for the material sample at the predetermined temperature. The laser beam may be a visible laser and/or an infrared laser. The thermal control mechanism comprises a thermal controller coupled to an induction coil apparatus and a temperature sensor. The sample holder comprises a refractory metal consisting of one or more of a niobium/molybdenum alloy and a tantalum/tungsten alloy.

Provide herein is a refractometer, optically transmissive structure, and method of making. The structure has a first surface disposing a light source. A second surface is configured and disposed to provide an angular light reflective interface at, or proximate therewith, a fluid being sensed. A third surface disposes an optical sensor. The optically transmissive structure has at least one of the light source and the optical sensor directly incorporated, bonded, or adhered therewith or has at least one light blocker configured and disposed to block a portion of light being directed or reflected toward the third surface.

Systems and methods for determining temperature or temperature related variables using a sensor having a measurement surface include a sensor body having one or more walls and containing an intermediary material, a window providing a measurement surface, a first temperature sensor obtaining a first temperature at or near the window, a second temperature sensor located within the intermediary material, and a processor configured to receive the first temperature and the second temperature and determine a temperature adjustment based on those temperatures. The temperature adjustment can be used to adjust a value of a temperature related variable based on the temperature at the measurement surface, for example for calculating a refractive index of a fluid. Additional temperature sensors may be included and further included in the determination of the temperature adjustment.

A refractometer includes an enclosure, a single use prism, a light source, and an index of refraction (IoR) sensor. The single use prism is removably disposed within the enclosure. The light source and IoR sensor are disposed within the housing and are configured to be repeatably used with a series of single use prisms of similar construction. One single use prism can be removed after being used, and a new single use prism can be installed in the enclosure for use with the same light source and IoR sensor as were used with the first prism.

The present disclosure embodies an improved optical instrument that includes an embodied fitting to the standardized probe with the optical structure to facilitate refractometer optics to the probe tip with a turbidity and/or color meter to form an embodied optical multimeter.

Systems and methods for determining temperature or temperature related variables using a sensor having a measurement surface include a sensor body having one or more walls and containing an intermediary material, a window providing a measurement surface, a first temperature sensor obtaining a first temperature at or near the window, a second temperature sensor located within the intermediary material, and a processor configured to receive the first temperature and the second temperature and determine a temperature adjustment based on those temperatures. The temperature adjustment can be used to adjust a value of a temperature related variable based on the temperature at the measurement surface, for example for calculating a refractive index of a fluid. Additional temperature sensors may be included and further included in the determination of the temperature adjustment.