University of California

Robert M Glaeser

Bong-Gyoon Han

Jian Jin

Osip Schwartz

Holger Mueller

Jeremy J Axelrod

Rossana Cambie

Sara Campbell

Carter Turnbaugh

A ponderomotive phase plate, also called a laser phase plate or standing wave optical phase plate, has a first minor and a second minor that define an optical cavity. An electron beam passes through a focal spot of the optical cavity. A laser with variable polarization angle of laser light is coupled to the optical cavity. A standing wave of polarized laser light, with an anti-node at the focal spot of the optical cavity, causes variable modulation of the electron beam. The variable modulation of the electron beam is controllable by the variable polarization angle of the laser light. In a transmission electron microscope, an image plane receives the electron beam modulated by the standing wave optical phase plate. An image formed at the image plane is based on the variable polarization angle of the polarized laser light.

Use of optical polarization states to control a ponderomotive phase plate

This disclosure provides systems, methods, and apparatus related to graphene. In one aspect, a method includes submerging a frame support in an etching solution that is contained in a container. A growth substrate, a graphene sheet disposed on the growth substrate, and a primary support disposed on the graphene sheet is placed on a surface of the etching solution. The growth substrate is dissolved in the etching solution to leave the graphene sheet and the primary support floating on a surface of the etching solution. The etching solution in the container is replaced with a washing solution. The washing solution is removed from the container so that the graphene sheet becomes disposed on the frame support.

Methods of supporting a graphene sheet disposed on a frame support

This disclosure provides systems, methods, and apparatus related to arrangements including electron microscopy grids. In one aspect an arrangement includes an electron microscopy grid. The electron microscopy grid comprises a first surface and a second surface, with the first surface having a holey carbon film disposed thereon. A plurality of lipid molecules are disposed in a hole in the holey carbon film. Each lipid molecule of the plurality of lipid molecules has a hydrophilic head and a hydrophobic tail. A biotin-binding protein is attached to the hydrophilic heads of the plurality of lipid molecules. The biotin-binding protein is crystalline.

Stable support films for electron microscopy

An optical cavity is defined by a first mirror and a second mirror. The first mirror has a front surface that includes a first concave mirror. The second mirror has a front surface that includes a second concave mirror. The optical cavity has a resonant optical mode with a small focal spot size. The optical cavity may be used in a method of enhancing phase contrast in an electron beam image, and associated system for electron beam imaging or electron-beam spectroscopy, with a transmission electron beam microscope.

Optical-cavity based ponderomotive phase plate for transmission electron microscopy

This disclosure provides systems, methods, and apparatus related to the preparation of electron microscopy specimens. In one aspect, a method includes providing an electron microscopy grid. An aqueous suspension including an electron microscopy sample is deposited on the electron microscopy grid. A portion of the aqueous suspension is removed from the electron microscopy grid. A volatile surfactant is contacted to the aqueous suspension. A thickness of aqueous suspension is allowed to decrease over a period of time. The aqueous suspension is then frozen.

Methods and apparatus for preparing aqueous specimens for electron microscopy using volatile surfactants

A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

Microfabricated high-bandpass foucault aperture for electron microscopy

A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

Growing community of inventors

Berkeley, CA, United States of America

Robert M Glaeser