Abstract: Systems and methods for converting linearly polarized light to azimuthally or radially polarized light. A composite half-wave plate assembly includes a plurality of angular half-wave plate sections. Each of the plurality of angular half-wave plate sections have two congruent sides that meet at an apex. The plurality of half-wave plates are arranged such that the apexes of the plurality of angular half-wave plate sections all meet at a point substantially at a center of the composite half-wave plate, and a characteristic c-axis associated with a given angular half-wave plate section is aligned differently from the respective characteristic c-axes of at least two angular half-wave plate sections in substantial contact with the two sides of the given angular half-wave plate section. A fixation element engages the plurality of angular half-wave plate sections to maintain the angular half-wave plate sections in a desired arrangement.

Abstract: Systems and methods for shifting the phase of incident light to induce a continuous phase variation in an azimuthal direction. A phase mask assembly has a first surface and a second surface. The first surface and the second surface are configured such that the distance between the first surface and the second surface varies continuously in an azimuthal direction around the phase mask. This mask can be used in a coronagraph system to effectively suppress the on-axis star image for the detection of off-axis planets.

Abstract: Systems and methods for attenuating light from undesired sources in a coronagraph apparatus are provided. The coronagraph includes a first imaging lens that receives light representing a desired image and an undesired central image and a reimaging system that mitigates the undesired central image. The reimaging system includes a composite half-wave plate assembly that includes a plurality of angular half-wave plate sections. Each of the plurality of angular half-wave plate sections have two congruent sides that meet at an apex substantially at a center of the composite half-wave plate. A characteristic c-axis associated with a given angular half-wave plate section is aligned differently from the respective characteristic c-axes of at least two angular half-wave plate sections in substantial contact with the two sides of the given angular half-wave plate section. A fixation element engages the half-wave plate sections to maintain the angular half-wave plate sections in a desired arrangement.

Abstract: A technique for generating very-high-order Hermite functions needed for accurately simulating operation of various devices and structures involving propagation of electromagnetic waves. By using modified recursion formulas, the technique generates asymptotic Hermite functions, smooth Hermite functions or optimized smooth Hermite functions, allowing for very high orders of the functions to be generated without the intermediate function values becoming so large as to exceed the capacity of conventional computers. The disclosed method for generating smooth Hermite functions provides for generation of well-behaved functions of order 30,000 or higher.

Abstract: A method for aligning the optical surfaces of a high extraction annular ring resonator which includes a scraper mirror with a decentered aperture. A probe beam is directed into the resonator cavity through the decentered aperture in the scraper mirror, and a visual and quantitative assessment of the amount of compact leg tilt and rear cone decentration is made. The optical surfaces are then repositioned into alignment based upon the results of the assessment.

Abstract: A method for aligning the optical surfaces of the high extraction annular ring resonator which includes a scraper mirror with a decentered aperture. A probe beam, from an external laser, is directed into the resonator cavity through the decentered aperture in the scraper mirror. The symmetrical properties of the probe beam near and far field intensity distribution patterns are used to align the optical surfaces within the cylindrical ring resonator.

Abstract: A laser mode control system for suppressing anti-symmetric resonance modes of a beam of radiation in a laser resonator cavity. The system includes a main resonator cavity in which a beam of radiation having symmetric and anti-symmetric resonance modes propagates. The main resonator cavity has at least one exit plane at a first end of the cavity through which the propagating beam of radiation passes. The system further includes an external cavity located outside of the main resonator cavity and adjacent to the exit plane. The external cavity includes a mirror for reflecting the beam of radiation passing through the exit plane and for flipping a mode profile associated with the beam of radiation upon the beam of radiation being reflected from the mirror. The external cavity also includes a partially transmissive medium between the mirror and the main resonator cavity for introducing losses to the beam of radiation in the external cavity.

Abstract: In accordance with the teachings of the present invention, a system and method are provided for steering a beam of optical radiation. The system includes a dividing telescope microlens array for receiving a beam of optical radiation directed along a first path and dividing the beam into a plurality of divided beam columns. A steering microlens array collectively redirects each of the divided beams along a second path. The system further includes a compensation lens for compensating for phase differences which may otherwise exist among the redirected divided beam columns. The redirected divided beams are then combined by way of a combining microlens array to provide a recombined far-field beam of optical radiation directed along the second path.

Abstract: A free-electron laser system and optical polarization conversion are provided for producing azimuthal polarization and radial polarization laser beams. The free-electron laser system includes a helical wiggler for generating a transverse magnetic field around a beam axis. An electron beam is projected along the beam axis and interacts with the transverse magnetic field so as to induce spontaneous and stimulated emission of optical radiation. A resonator cavity is formed by a pair of mirrors in which the optical radiation oscillates therein. The laser system directly produces an azimuthal polarization laser beam as an output. The laser system may further be coupled to an optical polarization converter which includes a pair of optical half-wave plates having a forty-five degree (45.degree.) optical axis difference therebetween. The azimuthal polarization laser beam is transmitted through the optical polarization converter so as to generate a radial polarization output beam.

Abstract: A laser resonator is provided for producing a radially polarized laser beam. The laser resonator includes an active laser medium disposed between a highly reflective end mirror and an opposing partial transmission mirror which define a laser resonator cavity therebetween for producing oscillating optical radiation. A conical Brewster window is further located within the laser resonator cavity and has an optically transparent medium oriented in accordance with the polarizing (i.e., Brewster) angle. As the optical radiation oscillates within the resonator cavity, the conical Brewster window causes the radiation transmitted therethrough to have a radial polarization. Accordingly, the laser resonator produces a laser output which has a radially polarized electric field associated therewith.