A method for visualizing details in a sample including directing an excitation beam to an excitation location below a surface of the sample, to generate signals in the sample; directing an interrogation beam toward the excitation location of the sample; directing a signal enhancement beam to the sample, to raise a temperature of a portion of the sample by 5 Kelvin or less, compared to a temperature of the portion of the sample in absence of the signal enhancement beam; detecting a portion of the interrogation beam returning from the sample that is indicative of the generated signals.

A three-dimensional measurement device includes: an optical system including an optical device that splits an incident light, irradiates a measurement object with a measurement light, irradiates a reference plane with a reference light, and combines at least part of the reflected measurement light with at least part of the reflected reference light to emit a combined light; a first light emitter that emits a first light that has a first wavelength; a second light emitter that emits a second light that has a second wavelength; a first imaging device that takes an image of an output light output from the optical device in which the first light enters; a second imaging device that takes an image of an output light output from the optical device in which the second light enters; and a control device that executes three-dimensional measurement of the measurement object.

A method for characterising structures etched in a substrate, such as a wafer is disclosed. The method includes, for at least one structure, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top side of the substrate, for measuring with a measurement beam, at least one depth data relating to a depth of said HAR structure, wherein the method also includes a first adjusting step for adjusting a diameter, at the top surface, of the measurement beam according to at least one top-CD data relating to a width of said HAR structure. The invention further relates to a system implementing such a method.

A method for characterising structures etched in a substrate, such as a wafer is disclosed. The method includes at least one structure etched in the substrate, at least one imaging step including the following steps: capturing, with an imaging device positioned on a top side of said substrate, at least one image of a top surface of the substrate, and measuring a first data relating to the structure from at least one captured image, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top side, for measuring with a measurement beam positioned on the structure, at least one depth data relating to a depth of said structure; wherein the method also comprises a first adjusting step for adjusting said measurement beam according to the first data. A system implementing such a method is also disclosed.

A method of improving axial resolution of interferometric measurements of a 3D feature of a sample may comprise illuminating the feature using a first limited number of successively different wavelengths of light at a time; generating an image of at least the 3D feature based on intensities of light reflected from the feature at each of the successively different wavelengths of light; measuring a fringe pattern of intensity values for each corresponding pixel of the generated images; resampling the measured fringe patterns as k-space interferograms; estimating interference fringe patterns for a spectral range that is longer than available from the generated images using the k-space interferograms; appending the estimated interference fringe patterns to the respective measured fringe patterns; and measuring the height or depth of the 3D feature using the measured interference fringe patterns and appended estimated fringe patterns.

The present disclosure provides a method of analyzing an area of interest of a sample material which comprises directing a first radiation to a first area of interest, the first radiation having frequencies within a terahertz frequency range. The method also comprises receiving a first signal THz.sub.1 being a quantity related to radiation received from the first area of interest in response to directing the first radiation to the first area of interest, the first signal THz.sub.1 being dependent on a first property and on a second property of the first area of interest. Further, the method comprises directing a second radiation to the first area of interest, the second radiation having frequencies within a frequency range that is different to that of the first radiation. In addition, the method comprises receiving a second signal IR1 being a quantity related to radiation received from the first area interest in response to directing the second radiation to the first area of interest, the second signal IR1 being dependent on the second property of the first area of interest. The method also comprises scaling or co-registering times of flight associated with the first signal THz.sub.1 and the second signal IR.sub.1 such that the scaled co-registered time of flight corresponds to matching depths within the sample material. Further, the method comprises analyzing the first signal THz1 using the second signal IR.sub.1 to identify first information indicative of the first property of the first area of interest.

Provided is a shape measurement system in order to perform three-dimensional measurement corresponding to a measurement object having various shapes, which includes a measurement probe, a probe tip, and a processor. The probe tip includes an optical element that is configured to irradiate an object with measurement light and a cylindrical unit that is configured to lock the optical element. The processor is configured to calculate an optical path length from the optical element to an object based on reflected light of the measurement light with which the object is irradiated; and calculate a three-dimensional shape of the object based on the input information and the optical path length.

Aspects of the present disclosure provide improved techniques for imaging a subject's retina fundus. Some aspects relate to an imaging apparatus that may be substantially binocular shaped and/or may house multiple imaging devices configured to provide multiple corresponding modes of imaging the subject's retina fundus. Some aspects relate to techniques for imaging a subject's eye using white light, fluorescence, infrared (IR), optical coherence tomography (OCT), and/or other imaging modalities that may be employed by a single imaging apparatus. Some aspects relate to improvements in white light, fluorescence, IR, OCT, and/or other imaging technologies that may be employed alone or in combination with other techniques. Some aspects relate to multi-modal imaging techniques that enable determination of a subject's health status. Imaging apparatuses and techniques described herein provide medical grade retina fundus images and may be produced or conducted at low cost, thus increasing access to medical grade imaging.

A microscope is provided which includes an optical module, an OCT module, and a control device. The optical module is configured to generate optical image representations. The OCT module is configured to generate tomographic recordings. The control device is configured to determine the relative spatial position of a marking element, in each case from an optical image representation of the marking element and from a tomographic recording of the same marking element.

Provided herein is technology relating to analysis of images and particularly, but not exclusively, to methods and systems for determining the area and/or volume of a region of interest using optical coherence tomography data. Some embodiments provide for determining the area and/or volume of a lesion in retinal tissue using three-dimensional optical coherence tomography data and a two-dimensional optical coherence tomography fundus image.