Various methods, systems and apparatus are provided for imaging and sensing using interferometry. In one example, a system includes an interferometer; a light source that can provide light to the interferometer at multiple wavelengths (λ.sub.i); and optical path delay (OPD) modifying optics that can enhance contrast in an interferometer output associated with a sample. The light can be directed to the sample by optics of the interferometer. The interferometer output can be captured by a detector (e.g., a camera) at each of the multiple wavelengths (λ.sub.i). In another example, an apparatus includes an add-on unit containing OPD that can enhance contrast in an interferometer output associated with a sample illuminated by light at a defined wavelength (λ.sub.i). A detector can be attached to the add-on unit to record the interferometer output at the defined wavelength (λ.sub.i).

Various methods, systems and apparatus are provided for imaging and sensing using interferometry. In one example, a system includes an interferometer; a light source that can provide light to the interferometer at multiple wavelengths (λ.sub.i); and optical path delay (OPD) modifying optics that can enhance contrast in an interferometer output associated with a sample. The light can be directed to the sample by optics of the interferometer. The interferometer output can be captured by a detector (e.g., a camera) at each of the multiple wavelengths (λ.sub.i). In another example, an apparatus includes an add-on unit containing OPD that can enhance contrast in an interferometer output associated with a sample illuminated by light at a defined wavelength (λ.sub.i). A detector can be attached to the add-on unit to record the interferometer output at the defined wavelength (λ.sub.i).

A method is provided that comprises printing FEM wafers having different predefined focus offsets and multiple corresponding sites, measuring signals from the sites, and quantifying a focus inaccuracy by comparing the measured signals from the corresponding sites across the wafers.

A phase object visualization apparatus includes: an illumination optical system 11 that illuminates a phase object; an image formation optical system 12 that forms an image from light from sample S that corresponds to the phase object; and light blocking unit 10 for blocking light, the light blocking unit 10 being disposed between the sample S and an image plane formed by the image formation optical system 12, and including an aperture at a position decentered from the optical axis of the image formation optical system 12. The position of the aperture is such that an area occupied on the aperture by 0-order diffraction light from the sample S illuminated by the illumination optical system 11 becomes smaller than the total area of the aperture.

The present invention relates to a device for phase stepping in phase contrast image acquisition, the device (1) comprising: a mobile grating (10); a guiding element (11); a restoring element (12); and a locking element (13); wherein the guiding element (11) is configured to guide the mobile grating (10) between a first position (2) and a second position (3); wherein the restoring element (12) is configured to apply a force to the mobile grating (10); wherein the force is directed from the first position (2) to the second position (3); and wherein the locking element (13) is configured to releasably lock the mobile grating (10) in the first position (2). In an example, during the motion of the mobile grating (10) back to equilibrium, a decoder (11a) for the position of the mobile grating (10) along the guiding element (11) may trigger at least four measurement frames over a period of at least 2*Pi. The invention provides a device (1) for phase stepping in phase contrast image acquisition which provides a fast image acquisition without a significant delay and which reduces positional inaccuracies and which avoids back-lash.

An enhanced single particle interferometric reflectance imaging system includes an illumination source configured to produce illumination light along an illumination path toward a target substrate. The target substrate can be configured to reflect the illuminating light along one or more collection paths toward one or more imaging sensors. The target substrate includes a base substrate having a first reflecting surface and a transparent spacer layer having a first surface in contact with the first reflecting surface and a second reflecting surface on a side opposite to the first surface. The transparent spacer layer has a predefined thickness that is determined as a function of a wavelength of the illuminating light and produces a predefined radiation pattern of optical scattering when nanoparticles are positioned on or near the second reflective surface. In addition, one or more of the collection paths can also include an amplitude mask selected to match the radiation pattern.

An enhanced single particle interferometric reflectance imaging system includes an illumination source configured to produce illumination light along an illumination path toward a target substrate. The target substrate can be configured to reflect the illuminating light along one or more collection paths toward one or more imaging sensors. The target substrate includes a base substrate having a first reflecting surface and a transparent spacer layer having a first surface in contact with the first reflecting surface and a second reflecting surface on a side opposite to the first surface. The transparent spacer layer has a predefined thickness that is determined as a function of a wavelength of the illuminating light and produces a predefined radiation pattern of optical scattering when nanoparticles are positioned on or near the second reflective surface. In addition, one or more of the collection paths can also include an amplitude mask selected to match the radiation pattern.

A phase object visualization apparatus includes: an illumination optical system 11 that illuminates a phase object; an image formation optical system 12 that forms an image from light from sample S that corresponds to the phase object; and light blocking unit 10 for blocking light, the light blocking unit 10 being disposed between the sample S and an image plane formed by the image formation optical system 12, and including an aperture at a position decentered from the optical axis of the image formation optical system 12. The position of the aperture is such that an area occupied on the aperture by 0-order diffraction light from the sample S illuminated by the illumination optical system 11 becomes smaller than the total area of the aperture.

A phase object visualization apparatus includes: an illumination optical system 11 that illuminates a phase object; an image formation optical system 12 that forms an image from light from sample S that corresponds to the phase object; and light blocking unit 10 for blocking light, the light blocking unit 10 being disposed between the sample S and an image plane formed by the image formation optical system 12, and including an aperture at a position decentered from the optical axis of the image formation optical system 12. The position of the aperture is such that an area occupied on the aperture by 0-order diffraction light from the sample S illuminated by the illumination optical system 11 becomes smaller than the total area of the aperture.

The present invention relates to a device for phase stepping in phase contrast image acquisition, the device (1) comprising: a mobile grating (10); a guiding element (11); a restoring element (12); and a locking element (13); wherein the guiding element (11) is configured to guide the mobile grating (10) between a first position (2) and a second position (3); wherein the restoring element (12) is configured to apply a force to the mobile grating (10); wherein the force is directed from the first position (2) to the second position (3); and wherein the locking element (13) is configured to releasably lock the mobile grating (10) in the first position (2). In an example, during the motion of the mobile grating (10) back to equilibrium, a decoder (11a) for the position of the mobile grating (10) along the guiding element (11) may trigger at least four measurement frames over a period of at least 2*Pi. The invention provides a device (1) for phase stepping in phase contrast image acquisition which provides a fast image acquisition without a significant delay and which reduces positional inaccuracies and which avoids back-lash.