A method and a system for determining relative position of an element of an optical system of an assembly for processing or measuring an object along a measurement line, involve generating a measurement beam and a reference beam of low coherence optical radiation. The measurement and reference beams, alternately or in combination, have a main beam and a multiplexed additional beam. The measurement beam, led toward the element of the optical system, and back-reflected, is superimposed on the reference beam in a region of common incidence of an interferometric optical sensor arrangement. Position or frequency of a main interference fringe pattern and an additional interference fringe pattern is detected.

The invention provides a method and apparatus for applying spatial filtering the optical beam of a free space optical coherence tomography (OCT) system substantially without problematic reflections back to the optical source. The invention teaches spatially filtering the reference beam of the OCT system which is typically designed to provide isolation of the optical source from undesirable optical feed-back, thereby achieving spatial filtering without generating undesirable reflections back to the optical source. Various embodiments are taught.

Provided herein are devices and systems comprising an illumination module configured to provide a source light to an optical interference module, which converts the source light to a line of light and processes light signal; an interference objective module, which handles light from the optical interference module and processes light signal generated from a sample; a two-dimensional camera configured to receive a backscattered interference signal from the sample, and a data processing module which processes the interference signal into an image.

Optical pressure sensor assemblies that can be used with existing catheters and imaging systems. Pressure sensors may be compatible with atherectomy and occlusion-crossing catheters, where intravascular pressure measurements at various vessel locations are needed to determine treatment efficacy. The pressure sensors may employ an optical pressure measurement mechanism using optical interferometry, and may be integrated with existing imaging modalities such as OCT. The pressure sensor assemblies may include a movable membrane that deflects in response to intravascular pressure; an optical fiber that transmits light to the movable membrane and receives light reflected or scattered back from the movable membrane into the fiber; and a processor or controller configured to determine the distance traveled by the light received in the fiber from the movable membrane, where the distance traveled is proportional to the intravascular pressure exerted against the membrane.

A system and method are described for performing tear film structure measurement. A broadband light source illuminates the tear film. A spectrometer measures respective spectra of reflected light from at least one point of the tear film. A color camera performs large field of view imaging of the tear film, so as to obtain color information for all points of the tear film imaged by the color camera. A processing unit calibrates the camera at the point measured by the spectrometer so that the color obtained by the camera at the point matches the color of the spectrometer at the same point. The processing unit determines, from the color of respective points of the calibrated camera, thicknesses of one or more layers of the tear film at the respective points. Other applications are also described.

Optical pressure sensor assemblies that can be used with existing catheters and imaging systems. Pressure sensors may be compatible with atherectomy and occlusion-crossing catheters, where intravascular pressure measurements at various vessel locations are needed to determine treatment efficacy. The pressure sensors may employ an optical pressure measurement mechanism using optical interferometry, and may be integrated with existing imaging modalities such as OCT. The pressure sensor assemblies may include a movable membrane that deflects in response to intravascular pressure; an optical fiber that transmits light to the movable membrane and receives light reflected or scattered back from the movable membrane into the fiber; and a processor or controller configured to determine the distance traveled by the light received in the fiber from the movable membrane, where the distance traveled is proportional to the intravascular pressure exerted against the membrane.

A light source, a standing wave forming unit, a detector, and an absorbance calculating unit. The light source irradiates a sample with light. The standing wave forming unit forms, in the sample, an acoustic standing wave perpendicular to a surface of the sample. A node of the acoustic standing wave is positioned at a predetermined distance from the surface of the sample, the light from the light source entering the surface of the sample. The detector detects light emitted from the surface of the sample, and is disposed on the surface of the sample on a side where the light source is disposed. The absorbance calculating unit obtains absorbance.

Optical pressure sensor assemblies that can be used with existing catheters and imaging systems. Pressure sensors may be compatible with atherectomy and occlusion-crossing catheters, where intravascular pressure measurements at various vessel locations are needed to determine treatment efficacy. The pressure sensors may employ an optical pressure measurement mechanism using optical interferometry, and may be integrated with existing imaging modalities such as OCT. The pressure sensor assemblies may include a movable membrane that deflects in response to intravascular pressure; an optical fiber that transmits light to the movable membrane and receives light reflected or scattered back from the movable membrane into the fiber; and a processor or controller configured to determine the distance traveled by the light received in the fiber from the movable membrane, where the distance traveled is proportional to the intravascular pressure exerted against the membrane.

A light source, a standing wave forming unit, a detector, and an absorbance calculating unit. The light source irradiates a sample with light. The standing wave forming unit forms, in the sample, an acoustic standing wave perpendicular to a surface of the sample. A node of the acoustic standing wave is positioned at a predetermined distance from the surface of the sample, the light from the light source entering the surface of the sample. The detector detects light emitted from the surface of the sample, and is disposed on the surface of the sample on a side where the light source is disposed. The absorbance calculating unit obtains absorbance.

Provided herein are devices and systems comprising an illumination module configured to provide a source light to an optical interference module, which converts the source light to a line of light and processes light signal; an interference objective module, which handles light from the optical interference module and processes light signal generated from a sample; a two-dimensional camera configured to receive a backscattered interference signal from the sample, and a data processing module which processes the interference signal into an image.