University of Minnesota

James R Leger

Qiwen Zhan

William Minster Kunkel

Di Lin

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium for managing beam shaping in gradient refractive index (GRIN) media are provided. In one aspect, a method includes specifying a field evolution throughout a gradient-index (GRIN) medium and generating a refractive index profile of the GRIN medium based on the specified field evolution in the GRIN medium. Diffraction effects are considered in solving for the refractive index profile. The index profile is found by specifying a desired beam transformation throughout the GRIN medium and solving a series of phase retrieval problems. The GRIN medium can be two-dimensional (2D) or three-dimensional (3D).

Managing electromagnetic field propagation in gradient-index media

A solid immersion tunneling ellipsometer and methods relating thereto may include a solid immersion apparatus (e.g., a prism or an objective lens in combination with a solid immersion lens) that facilitates optical tunneling and provide information that can be used in the determination of one or more characteristics (e.g., thickness, index of refraction, etc.) of samples (e.g., thin films, ultrathin films, etc.).

Ellipsometry methods and apparatus using solid immersion tunneling

An ellipsometer apparatus and method for use in providing an image of at least a portion of a sample includes an objective lens having a focal plane at which a sample plane of a sample is positioned. Linearly polarized light normal to the sample plane incident on the objective lens is provided, and the incident linearly polarized light is focused onto the sample. At least a portion of the focused incident polarized light is reflected by the sample resulting in reflected light. Spatial filtering is used to modify at least a portion of the incident or the reflected light. An analyzer portion is operable to generate polarization information based on the reflected light.

Imaging ellipsometry

An ellipsometer and ellipsometry method uses radial symmetry. For example, circularly polarized light may be focused to a spot on a sample using an objective lens and reflected therefrom. A radially symmetric ellipsometric signal based on the reflected light and representative of at least one characteristic of the sample may be attained using a radially symmetric analyzer apparatus, e.g., a pure Polarization rotator such as two half wave plates and a radially symmetric analyzer such as a birefringent lens.

Ellipsometer using radial symmetry

Method for making a custom phase-conjugating diffractive mirror for a laser resonator comprising the steps of: (a) choosing a specified beam mode profile a.sub.1 (x,y) that will suit need of said designer, (b) calculating the mode profile b(x',y') which is a value of the specified beam a.sub.1 (x,y) that is propagated to the reflection surface of the diffractive mirror and (c) calculating mirror reflectance t(x',y') which reflects phase conjugate of b(x',y'). A method for fabricating such a mirror is shown. Another aspect of the invention is the addition of a phase adjusting element into a laser resonator, and compensating for the addition of a phase adjusting element in the design of other phase-adjusting elements such as the mirrors.

Phase grating and mode-selecting mirror for a laser

Method for making a distortion-compensating phase-adjustment element for a laser. One type of distortion to be compensated for is heat distortion. Also described is a method for making a custom phase-conjugating diffractive mirror for a laser resonator comprising the steps of: (a) choosing a specified beam mode profile a.sub.1 (x,y), (b) calculating the mode profile b(x',y') which is a value of the specified beam a.sub.1 (x,y) that is propagated to the reflection surface of the diffractive mirror and (c) calculating mirror reflectance t(x',y') which reflects phase conjugate of b(x',y') and corrects for distortions such as heat. A method for fabricating such a mirror is shown. Another aspect of the invention is the addition of a phase adjusting element into a laser resonator, and compensating for the addition of a phase adjusting element in the design of other phase-adjusting elements such as the mirrors and correcting for distortions such as heat.

Distortion-compensated phase grating and mode-selecting mirror for a

Phase conjugating difractive elements and method

Method for making a custom phase-conjugating diffractive mirror for a laser resonator comprising the steps of: (a) (a) choosing a specified beam mode profile a.sub.i (x,y) that will suit need of said designer, (b) calculating the mode profile b(x',y') which is a value of the specified a.sub.i (x,y) that is propagated to the reflection surface of the diffractive mirror and (c) calculating mirror reflectance t(x',y') which reflects phase conjugate of b(x',y'). A method for fabricating such a mirror is shown. Another aspect of the invention is the addition of a phase adjusting element into a laser resonator, and compensating for the addition of a phase adjusting element in the design of other phase-adjusting elements such as the mirrors.

Growing community of inventors

Plymouth, MN, United States of America

James R Leger