Abstract: A diffractive optical element in which the maximum optical path length of light is an integral multiple of each of a plurality of wavelengths includes a diffractive grating configured by combining a first member and a second member having a refractive index lower than a refractive index of the first member and having dispersion higher than a dispersion of the first member. At least one of the first member and the second member is made of a glass material, and the diffractive grating is formed by the glass material which is heated to be softened using a thermal press forming, and has a concave grating shape that has a grating height increasing from a central part toward a peripheral part.

Abstract: An optical communication system includes a transceiver with a light source, a transition lens and an optical medium. Each of the light source, the transition lens and the optical medium define a corresponding axis. The light source defines a normal launch axis. The transition lens defines an optical axis. The optical medium defines a longitudinal axis. A relative misalignment from a coaxial alignment of the corresponding axes of at least one the light source, the transition lens and the optical medium is used to reduce a back reflection incident at the light source. Such misalignments can be achieved by one or both of angular adjustments and offsets of the axes.

Abstract: An ocular optical system used to view an image displayed on an image display surface, which includes a first lens having positive refractive power, a second lens of meniscus shape having negative refractive power with its concave surface facing the image display surface side, and a third lens having positive refractive power arranged in this order from the image display surface side to a viewer side. A focal length of the first lens, a focal length of the second lens and a focal length of the entire system need to be determined suitably.

Abstract: A telescope optical system having an objective lens system and an eyepiece lens system; wherein: the objective lens system includes a multi-layer-type diffractive optical element (PFo), and cemented lenses (So1) provided with a lens having positive refractive power and a lens having negative refractive power; the eyepiece lens system includes a multi-layer-type diffractive optical element (PFe), and cemented lenses (Se1) provided with a lens having negative refractive power and a lens having positive refractive power; and the condition represented by: 2?|(Po/FNO)/{Pe/(?×m)}|?15 is satisfied, where Ko represents the power of the objective lens system, Kodoe represents the power of the diffractive optical element (PFo) of the objective lens system, and Po is defined as Po=Kodoe/Ko; Ke represents the power of the eyepiece lens system, Kedoe represents the power of the diffractive optical element (PFe) of the eyepiece lens system, and Pe is defined as Pe=Kedoe/Ke; and FNO represents the F-number of the objective

Abstract: An objective lens OL comprises: a first lens group G1 disposed on an object side, having positive refractive power as a whole and having a positive lens (plano-convex lens L1) which is disposed closest to the object and of which lens surface closest to the object is a plane or a surface having a low curvature, and at least one cemented lens (cemented lens CL12 or the like); a second lens group G2 disposed on an image side, having negative refractive power as a whole, and having a concave surface facing the image and a concave surface facing the object, which face each other; and a diffractive optical element GD in which two diffractive element constituents made from different optical materials are cemented, which has a diffractive optical surface D formed with diffraction grating grooves on the cemented surface, and which is disposed closer to the object than a position where a principal ray crosses the optical axis.

Abstract: A projection display 210 arranged to display an image to an observer 212 use waveguide techniques to generate a display defining a large exit pupil at the point of the observer 212 and a large field of view, while using a small image-providing light source device. The projection display 210 uses two parallel waveguides 214, 216 made from a light transmissive material. One waveguide 214 stretches the horizontal pupil of the final display and the other waveguide 216 stretches the vertical pupil of the final display and acts as a combiner through which the observer 212 views an outside world scene 220 and the image overlaid on the scene 220. In a color display, each primary color is transmitted within a separate channel R, G, B.

Abstract: The invention concerns to a method of producing a Fresnel Zone Plate (1) for applications in high energy radiation including the following steps: supply of a substrate (2) transparent for high energy radiation, deposition of a layer (3) of a metal, a metal alloy or a metal compound on a planar surface (4) of the substrate (2), calculating a three dimensional geometrical profile (5) with a mathematical model, setting up a dosage profile (6) for an ion beam of the ion beam lithography inverse to the calculated three dimensional geometrical profile (5) and milling a three dimensional geometrical profile (5) with concentric zones into the layer (3) with ion beam lithography by means of focused ion beam.

Abstract: Microscopy methods and apparatus in which one or more microfabricated optical elements (e.g., one or more Fresnel zone plates) operate as one or an array of objective lenses. A single object or a plurality of objects may be scanned in parallel. A single, low-numerical-aperture relay optic can be used with the one or more optical elements eliminating the need for one or more confocal pinhole apertures. When an array of optical elements is used, hundreds to thousands of objects can be imaged or inspected simultaneously onto a two-dimensional imaging device, such as a CCD array. The microfabricated optical elements can be readily configured for imaging with a solid immersion medium. Imaging resolutions on the order of one wavelength of the illumination source, and less, can be achieved.

Abstract: The solid-state imaging device includes light collecting elements each of which includes a first light-transmissive film group and a second light transmissive film group adjacent to each other. The first light-transmissive film group and the second light transmissive film group have mutually different effective refractive index distributions for guiding at least two types of incident light rays to the light receiving element.

Abstract: A zone plate includes a plurality of consecutively arranged, adjacent, and alternating first and second regions. The first regions are arranged to be substantially transparent to a first predetermined wavelength of radiation and a second predetermined wavelength of radiation that is different from the first predetermined wavelength of radiation. The second regions are arranged to be substantially opaque, diffractive, or reflective to the first predetermined wavelength of radiation and substantially transparent to the second predetermined wavelength of radiation.

Abstract: The optical system includes plural lens groups, a negative lens included in one lens group among the plural lens groups and formed of a first medium, a diffractive grating formed on at least one lens surface of the negative lens and being in contact with a second medium different from the first medium, and a positive lens included in the one lens group and formed of a third medium different from the first medium and the second medium. The first medium satisfies ndA?1.7 and 40??dA?55 where ndA represents a refractive index of the first medium for a d-line, and ?dA represents an Abbe number of the first medium for the d-line. The third medium satisfies ndC?1.55 and ?dC?60 where ndC represents a refractive index of the third medium for the d-line, and ?dC represents an Abbe number of the third medium for the d-line.

Abstract: Although, conventionally, there were two methods, (1) a wave was transmitted through a spiral phase plate and (2) a diffraction grating containing an edge dislocation was used, they incurred complication of a configuration and securement of a larger amount of space and were not efficient because each of the spiral wave generation methods needed an incident wave to be a plane wave and at least one time of imaging is necessary at the time of wave irradiation on an observation object. In order to efficiently generate the spiral wave having a sufficient intensity, a structure of edge dislocation is taken in into a pattern of the zone plate and a spiral pattern containing a discontinuous zone is formed. Moreover, a thickness and a quality of material that change the phase of the wave by an odd multiple of ? are selected for a material of the wave-blocking section in the pattern.

Abstract: In a collimator lens, in a case where divergent light emitted from a position P1 at a distance S1 from a second face enters the second face and imaging is performed at a position P2 at a distance S2 from a first face, in a temperature range of 0° C. to 60° C. and in a range of the emission wavelength of the light source which changes within the temperature range, and when a minimum value of a wavefront aberration of an image, which is generated at the position P2 by the divergent light emitted from the position P1 in a range of 0<S1/S2?50, is WF1, and when a minimum value of a wavefront aberration of an image, which is generated at the position P2 when parallel light satisfying S1=? enters the second face, is WF2, a relationship of WF1<WF2 is satisfied.

Abstract: A diffraction grating lens according to the present invention includes a lens body and a diffraction grating provided on the surface of the lens body, the diffraction grating including a plurality of annular zones having slopes inclined along a width direction and a plurality of step surfaces respectively located between the plurality of annular zones. At least one of the plurality of annular zones is light-transmissive across its entire area along the width direction, and in the at least one annular zone, a light transmittance near at least one of two ends along the width direction is smaller than a light transmittance near a central portion along the width direction.

Abstract: A variable focal length achromatic lens includes a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping points. The refractive lens includes a fluid chamber with a flat glass surface and an opposing elastic polydimethylsiloxane (PDMS) membrane surface. Inserting fluid volume through a pump system into the clear aperture region alters the membrane curvature and adjusts the refractive lens' focal position. Primary chromatic aberration is remarkably reduced through the coupling of the fluidic and diffractive lenses at a number of selected focal lengths.

Abstract: There is provided a diffractive multifocal lens, wherein a diffraction phase structure of a diffraction pattern has a structure expressed by the following formula: ? ? ( ? ) = { p 1 ? ? , 0 ? ? < w p 2 ? ( ? - 0.5 ) - q ? ? ? , w ? ? < 1 - w p 1 ? ( ? - 1 ) , 1 - w ? ? ? 1 ( 1 ) wherein ? indicates a position in a radial direction of the lens in one period of the diffraction pattern, and ?(?) indicates a value (radian) of a phase shift amount of light passing through the position of ? from the phase of light passing through a reference plane.

Abstract: An ophthalmic lens for providing a plurality of foci includes an optic having an anterior surface, a posterior surface, and an optical axis. The ophthalmic lens has a first region and a second region. The first region has a first refractive optical power and includes a first base curvature having a finite radius of curvature and a first phase plate having at least one diffraction order with a diffractive optical power. The first region is configured for forming a first focus and a second focus. The second region has a second refractive optical power and includes a second base curvature having a finite second radius of curvature that is different from the first radius of curvature and a second phase plate having at least one diffraction order with a diffractive optical power.

Abstract: Provided is an objective lens manufactured well by using a mold and an optical pickup apparatus including the same. The objective lens of the present invention includes a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. A first annular zone step provided in the first region has a step amount larger than step amounts of annular zone steps provided in other regions.

Abstract: A security device includes an optically variable device (OVD) having diffraction-based micro-optics including at least one moiré magnified visual representation of a micro-object. A diffractive structure provides micro-objects with unique optical effects when the OVD is viewed through the micro-object structure from a predetermined relative observation point. In addition to magnifying the micro-objects, the diffractive structure can impart optical effects such as change in observed color, enhanced contrast, animation of the observed visual representation, and change in size or shape of the observed visual representation. The micro-objects and the diffractive structure can be disposed on the same or different portions of a substrate. A method of making OVDs, and an article employing such OVDs are also disclosed.

Abstract: A zoneplate includes a first pattern having a first thickness, the first pattern including a first material, and a second pattern adjacent to the first pattern and having a second thickness larger than the first thickness, the second pattern including a second material, incident light incident on the first pattern from the outside passing through the first pattern, and incident light incident on the second pattern from the outside passing through the second pattern.

Abstract: A security element, security device and method of forming a security device wherein the security element includes focusing elements, a first group of image elements, and a second group of image elements, each image element being located in an object plane to be viewable through a focusing element, and being located a distance from the focusing element such that the focal point width of the focusing element in the object plane is substantially equal to the size of the image element or differs from the size of the image element by a predetermined amount.

Abstract: Provided is an objective lens that allows securing of a long working distance for a laser beam with a long wavelength and has a predetermined thickness or larger, and an optical pickup apparatus including the objective lens. In an objective lens of the present invention, a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. An optical super resolution with the laser beam of the BD standard is achieved by preventing a portion of the laser beam of the BD standard transmitted through the second region from contributing to spot formation.

Abstract: A lens system is presented having a diffractive optical power region. The diffractive optical power region has a plurality of concentric surface relief diffractive structures. A greater portion of light incident on a diffractive structure near the center point contributes to the optical power than light incident on a diffractive structure peripherally spaced therefrom.

Abstract: According to an aspect of the present invention, a spectral purity filter includes an aperture, the aperture being arranged to diffract a first wavelength of radiation and to allow at least a portion of a second wavelength of radiation to be transmitted through the aperture, the second wavelength of radiation being shorter than the first wavelength of radiation, wherein the aperture has a diameter greater than 20 ?m.

Abstract: An optical member including high refractive index layers having a great refractive index and low refractive index layers having a small refractive index, which are each relatively thin as compared with an optical length, disposed alternately in the lateral direction as to an optical axis. Each width of the high refractive index layers and the low refractive index layers is equal to or smaller than the wavelength order of incident light.

Abstract: Optical apparatus includes first and second diffractive optical elements (DOEs) arranged in series to diffract an input beam of radiation. The first DOE is configured to apply to the input beam a pattern with a specified divergence angle, while the second DOE is configured to split the input beam into a matrix of output beams with a specified fan-out angle. The divergence and fan-out angles are chosen so as to project the radiation onto a region in space in multiple adjacent instances of the pattern.

Abstract: An optical member including high refractive index layers having a great refractive index and low refractive index layers having a small refractive index, which are each relatively thin as compared with an optical length, disposed alternately in the lateral direction as to an optical axis. Each width of the high refractive index layers and the low refractive index layers is equal to or smaller than the wavelength order of incident light.

Abstract: An apparatus for measuring an image of a pattern to be formed on a semiconductor by scanning the pattern using a scanner, the apparatus including an EUV mask including the pattern, a zoneplate lens on a first side of the EUV mask and adapted to focus EUV light on a portion of the EUV mask at a same angle as an angle at which the scanner will be disposed with respect to a normal line of the EUV mask, and a detector arranged on another side of the EUV mask and adapted to sense energy of the EUV light from the EUV mask, wherein NAzoneplate=NAscanner/n and NAdetector=NAscanner/n*?, where NAzoneplate denotes a NA of the zoneplate lens, NAdetector denotes a NA of the detector, and NAscanner denotes a NA of the scanner, ? denotes an off-axis degree of the scanner, and n denotes a reduction magnification of the scanner.

Abstract: An apparatus for measuring an image of a pattern to be formed on a semiconductor by scanning the pattern using a scanner, the apparatus including an EUV mask including the pattern, a zoneplate lens on a first side of the EUV mask and adapted to focus EUV light on a portion of the EUV mask at a same angle as an angle at which the scanner will be disposed with respect to a normal line of the EUV mask, and a detector arranged on another side of the EUV mask and adapted to sense energy of the EUV light from the EUV mask, wherein NAzoneplate=NAscanner/n and NAdetector=NAscanner/n*?, where NAzoneplate denotes a NA of the zoneplate lens, NAdetector denotes a NA of the detector, and NAscanner denotes a NA of the scanner, ? denotes an off-axis degree of the scanner, and n denotes a reduction magnification of the scanner.

Abstract: An imaging optical system according to the present invention includes: at least one diffraction grating lens with a diffraction grating that is made up of q diffraction ring zones; and a stop. A surface of the at least one diffraction grating lens that has the diffraction grating is a lens surface that is located closest to the stop. Supposing the respective widths of diffraction ring zones that are located first, second, (m?1)th and mth closest to the optical axis of the optical system are identified by P1, P2, Pm-1 and Pm, at least one m that falls within the range 3<m?q satisfies the following Inequality (3): k = ( 1 P m - 1 · P m - 1 - P m P m - 1 · P m ) ( 1 P 1 · P 1 - P 2 P 1 · P 2 ) > 1.

Abstract: An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

Abstract: A diffractive optical element (1) composed of a ceramic, in which the optical characteristics are enhanced by enhancing the machining precision, is composed of an infrared-transmissive ceramic, and prominent portions (11) and groove portions (12) are repeatedly formed on a surface of the diffractive optical element (1). The average value of the surface roughness Ra within an optical effective area (10) of the surface of the diffractive optical element is 0.05 ?m or less, and the difference in the surface roughness Ra within the optical effective area (10) of the surface is 0.02 ?m or less.

Abstract: A diffractive optical element includes a first optical part and a second optical part bonded to each other with a bonded surface therebetween configured as a diffraction surface. In this diffractive optical element, the diffraction order of diffracted light with the largest quantity of light out of diffracted light for one of a plurality of kinds of laser beams obtained on the diffraction surface is different from the diffraction order for at least another laser beam.

Abstract: A light-condensing device and a method of fabricating the same are provided. The light-condensing device includes a central block, a pair of vertical diffraction grating blocks respectively located left and right of the central block, and a pair of horizontal diffraction grating blocks respectively located above and below the central block. The vertical diffraction grating blocks include parallel vertical diffraction gratings in the form of lines extending in the direction of a vertical axis, and the horizontal diffraction grating blocks include parallel horizontal diffraction gratings in the form of lines extending in the direction of a horizontal axis.

Abstract: A zone plate includes a plurality of consecutively arranged, adjacent, and alternating first and second regions. The first regions are arranged to be substantially transparent to a first predetermined wavelength of radiation and a second predetermined wavelength of radiation that is different from the first predetermined wavelength of radiation. The second regions are arranged to be substantially opaque, diffractive, or reflective to the first predetermined wavelength of radiation and substantially transparent to the second predetermined wavelength of radiation.

Abstract: An ophthalmic lens for providing a plurality of foci includes an optic having an anterior surface, a posterior surface, and an optical axis. The ophthalmic lens has a first region and a second region. The first region has a first refractive optical power and includes a first base curvature having a finite radius of curvature and a first phase plate having at least one diffraction order with a diffractive optical power. The first region is configured for forming a first focus and a second focus. The second region has a second refractive optical power and includes a second base curvature having a finite second radius of curvature that is different from the first radius of curvature and a second phase plate having at least one diffraction order with a diffractive optical power. The second region is configured for forming a third focus that is between the first focus and the second focus.

Abstract: An optical member includes high refractive index layers having a great refractive index and low refractive index layers having a small refractive index, which are each relatively thin as compared with an optical length, disposed alternately in the lateral direction as to an optical axis. Each width of the high refractive index layers and the low refractive index layers is equal to or smaller than the wavelength order of incident light.

Abstract: A dichromatic lens includes a plurality of zones being arranged on a lens structure, each of the zones having a specified radius and varying height. The lens structure focuses propagating light applicable to any intensity distribution for a plurality of wavelengths.

Abstract: In a refraction lens having an aspheric shape formed thereon and having a positive power, a diffraction grating is formed on at least one of the faces of the refraction lens. In order to reduce the curvature of field and the chromatic aberration in a well-balanced manner, the zonal pitch of the diffraction grating is constituted so as to satisfy the following conditional expression. [ eq . ? 19 ] 0.21 ? ? m 2 ? v d ? ? ? f h max < ? min < 0.30 ? ? m 2 ? v d ? ? ? f h max ( 1 ) Herein, ?min is a minimum zonal pitch 12; m is an order of diffraction; ?d is an Abbe number of the lens substrate material with respect to the d-line; ? is a wavelength; f is an effective focal length; and hmax is an effective radius 13 of the face on which the diffraction grating is formed.

Abstract: A virtual image display device is provided which displays a two-dimensional image for viewing a virtual image in a magnified form by a virtual optical system. The virtual image display device includes an optical waveguide (13) to guide, by internal total reflection, parallel pencil groups meeting a condition of internal total reflection, a first reflection volume hologram grating (14) to diffract and reflect the parallel pencil groups incident upon the optical waveguide from outside and traveling in different directions as they are so as to meet the condition of internal total reflection inside the optical waveguide and a second reflection volume hologram grating (15) to project the parallel pencil groups guided by internal total reflection inside the optical waveguide as they are from the optical waveguide by diffraction and reflection thereof so as to depart from the condition of internal total reflection inside the optical waveguide.

Abstract: An ophthalmic lens for providing a plurality of foci includes an optic having an anterior surface, a posterior surface, and an optical axis. The ophthalmic lens has a first region and a second region. The first region has a first refractive optical power and includes a first base curvature having a finite first radius of curvature and a first phase plate having at least one diffraction order with a diffractive optical power. The first region is configured for forming a first focus and a second focus. The second region has a second refractive optical power and includes a second base curvature having a finite second radius of curvature that is different from the first radius of curvature and a second phase plate having at least one diffraction order with a diffractive optical power. The second region is configured for forming a third focus that is between the first focus and the second focus.

Abstract: A system and method for uniform light generation in projection display systems. An illumination source comprises a light source to produce colored light, and a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source. The scrolling optics unit comprises a single light shaping diffuser to transform the colored light into the lines of colored light, an optical filter positioned in the light path after the light shaping diffuser, and a scrolling optics element positioned in the light path after the optical filter. The single light shaping diffuser is capable of simultaneously transforming colored light into lines of colored light having substantially uniform intensity to provide uniform illumination.

Abstract: A volume Fresnel zone plate and a method of producing such a device using a femtosecond laser for direct writing of zone plates. A volume zone plate has a number of Fresnel zone plate layers designed to focus light coherently to a single spot. Embodiments include both low numerical aperture (NA) and high NA zone plates, and provide a significant increase in overall diffraction efficiency over a single Fresnel zone plate.

Abstract: A pressing mold for optical lenses, which molds a ring-zone-type diffraction lens having a plurality of concentric ring zones, the mold including: diffraction action transfer surfaces configured to form diffraction action surfaces that diffract light passing through the diffraction lens; and step transfer surfaces configured to form step surfaces that connect the adjacent diffraction action surfaces of the diffraction lens, wherein surface roughness of the step transfer surfaces is larger than surface roughness of the diffraction action transfer surfaces.

Abstract: The invention includes a master lens, which initially focuses a laser pulse, and then the pulse passes through a zonal lenslet array, which uses different lenslet elements that provide for predetermined focal lengths so as to establish a three or two dimensional, predetermined dispersion of foci of the laser pulse. The zonal lenslet array of the present invention may be thought of as a variant of a Shack-Hartman wave front sensor, but used for an entirely different application.

Abstract: A lithographic apparatus includes a first diffraction grating configured to create a first plurality of spatially coherent radiation beams and a second diffraction grating configured to receive at least a portion of the first plurality of spatially coherent radiation beams and to create, based on the first plurality of spatially coherent radiation beams, a second plurality of spatially coherent radiation beams. The apparatus also includes a beam combiner adapted to redirect and combine at least a portion of the second plurality of spatially coherent radiation beams onto a surface of a substrate to form an interference pattern.

Abstract: An ophthalmic lens for providing a plurality of foci has an optic including an anterior surface, a posterior surface, and an optical axis. The ophthalmic lens further includes a central phase plate, an intermediate phase plate surrounding the central phase plate, and an outer refractive region. The central phase plate comprises a first base curvature having a first radius of curvature and is configured such that the lens is able to direct light to a first focus and a second focus corresponding different diffraction orders of the phase plate. The intermediate phase plate is configured to change the overall resultant distribution of light directed to the second focus. The outer refractive region has no diffractive optical power and surrounds the intermediate phase plate. The outer refractive region is configured to direct light to the second focus and has an aspheric shape configured to reduce an optical aberration.

Abstract: An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

Abstract: The invention relates to a device and a method for producing resist profiled elements. According to the invention, an electron beam lithography system is used to produce an electron beam, the axis of the beam being essentially perpendicular to a resist layer in which the resist profiled element is to be produced. The electron beam can be adjusted in terms of the electron surface dose in such a way that a non-orthogonal resist profiled element can be produced as a result of the irradiation by the electron beam.

Abstract: A method and objective apparatus are provided for implementing an enhanced phase contrast microscope. A focusing vortex lens, defined by a diffractive spiral zone plate (SZP) lens, is used for the objective for the phase contrast microscope. The SZP lens focuses and imparts a helical phase to incident illumination to image the specimen with spiral phase contrast. The spiral phase contrast microscope is sensitive to phase gradients in all sample axes. Replacing the objective of a microscope with the diffractive SZP lens of the invention immediately provides existing instruments with spiral phase contrast capability.