A direct-retina holographic projection system includes first and second spatial light modulators (SLMs) and a control module. The first SLM receives a beam of light and dithers the beam of light at a predetermined frequency to provide multiple instances of the beam of light. The second SLM receives the instances of the beam of light, displays an encoded phase hologram of a graphic image to be projected, and diffracts the instances of the beam of light to provide instances of the encoded phase hologram with the same graphic image but multiplied with dithered wavefronts. The control module: iteratively adjusts a parameter of the first SLM to generate the instances of the beam of light; and controls operation of the second SLM to, based on the instances of the beam of light, display multiple instances of the graphic image on a retina of an eye of a viewer.

A direct-retina holographic projection system includes first and second spatial light modulators (SLMs) and a control module. The first SLM receives a beam of light and dithers the beam of light at a predetermined frequency to provide multiple instances of the beam of light. The second SLM receives the instances of the beam of light, displays an encoded phase hologram of a graphic image to be projected, and diffracts the instances of the beam of light to provide instances of the encoded phase hologram with the same graphic image but multiplied with dithered wavefronts. The control module: iteratively adjusts a parameter of the first SLM to generate the instances of the beam of light; and controls operation of the second SLM to, based on the instances of the beam of light, display multiple instances of the graphic image on a retina of an eye of a viewer.

A method includes: producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse; forming a light beam of pulses at least from the modified pulses; and directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus.

A diffuser system (100) and method for optically diffusing a light beam (L1,L2). At least two transmissive diffuser windows (11,21) are provided. The diffuser windows (11,21) are arranged to sequentially diffuse the light beam (L1,L2) transmitted there through. The diffuser system (100) is configured to continuously rotate the diffuser windows (11,21) at an angular velocity (ω1,ω2) for homogenizing a diffusive pattern of the transmitted light beam (L1,L2). The diffuser windows (11,21) are configured to rotate around distinct rotation axes (C1,C2). The distinct rotation axes (C1,C2) are parallel and offset with respect to each other by a radial center distance (d12). A rotating subarea of the first diffuser window (11) partially overlaps a rotating subarea of the second rotating diffuser window (12) The partially overlapping rotating subareas define a beam window (W12) for homogenizing and diffusing the transmitted light beam (L1,L2).

A method includes: producing a light beam made up of pulses having a wavelength in the deep ultraviolet range, each pulse having a first temporal coherence defined by a first temporal coherence length and each pulse being defined by a pulse duration; for one or more pulses, modulating the optical phase over the pulse duration of the pulse to produce a modified pulse having a second temporal coherence defined by a second temporal coherence length that is less than the first temporal coherence length of the pulse; forming a light beam of pulses at least from the modified pulses; and directing the formed light beam of pulses toward a substrate within a lithography exposure apparatus.

A method for handling a mask is provided in accordance with some embodiments of the present disclosure. The method includes determining whether a particle is present on a contact surface of a mask. The mask is cleaned to remove the particle from the contact surface of the mask if the particle is present on the contact surface. The mask is disposed on a chuck after cleaning the mask, wherein the contact surface of the mask contacts the chuck when the mask is disposed on the chuck. A lithography process is performed using the mask disposed on the chuck.

An optical system comprising: an illumination system configured, to form a periodic illumination mode comprising radiation in a pupil plane of the optical system having a spatial intensity profile which is periodic in at least one direction, a measurement system configured to measure a dose of radiation which is received in an field plane of the optical system as a function of position in the field plane, and a controller configured to: select one or more spatial frequencies in the field plane at which variation in the received dose of radiation as a function of position is caused by speckle, and determine a measure of the variation of the received dose of radiation as a function of position at the selected one or more spatial frequencies, the measure of the variation in the received dose being indicative of speckle in the field plane.

Methods and apparatuses for measuring a plurality of structures formed on a substrate are disclosed. In one arrangement, a method includes obtaining data from a first measurement process. The first measurement process including individually measuring each of the plurality of structures to measure a first property of the structure. A second measurement process is used to measure a second property of each of the plurality of structures. The second measurement process includes illuminating each structure with radiation having a radiation property that is individually selected for that structure using the measured first property for the structure.

A diffuser system (100) and method for optically diffusing a light beam (L1,L2). At least two transmissive diffuser windows (11,21) are provided. The diffuser windows (11,21) are arranged to sequentially diffuse the light beam (L1,L2) transmitted there through. The diffuser system (100) is configured to continuously rotate the diffuser windows (11,21) at an angular velocity (1,2) for homogenizing a diffusive pattern of the transmitted light beam (L1,L2). The diffuser windows (11,21) are configured to rotate around distinct rotation axes (C1,C2). The distinct rotation axes (C1,C2) are parallel and offset with respect to each other by a radial center distance (d12). A rotating subarea of the first diffuser window (11) partially overlaps a rotating subarea of the second rotating diffuser window (12) The partially overlapping rotating subareas define a beam window (W12) for homogenizing and diffusing the transmitted light beam (L1,L2).

A method for handling a mask is provided in accordance with some embodiments of the present disclosure. The method includes determining whether a particle is present on a contact surface of a mask. The mask is cleaned to remove the particle from the contact surface of the mask if the particle is present on the contact surface. The mask is disposed on a chuck after cleaning the mask, wherein the contact surface of the mask contacts the chuck when the mask is disposed on the chuck. A lithography process is performed using the mask disposed on the chuck.