California Institute of Technology

The United States of America As Represented by the Administrator of the

United States of America As Represented by the Administrator of Nasa

Richard E Muller

Daniel W Wilson

Paul D Maker

Morteza Gharib

William J Kaiser

Thomas W Kenny

Frank Greer

Karl Y Yee

Cecile D Jung-Kubiak

Dominique Claire Fourguette

Siamak Forouhar

Darius Modarress

Victor E White

Frederic Taugwalder

James E Polk

Matthew R Dickie

Erika C Vote

Pantazis Mouroulis

Judith A Podosek

Colleen M Marrese-Reading

John R Anderson

Nima Rouhi

Micro-emitter arrays and methods of microfabricating such emitter arrays are provided. The microfabricated emitter arrays incorporate a plurality of emitters with heights greater than 280 microns with uniformity of +/&#x2212;10 microns arranged on a supporting silicon substrate, each emitter comprising an elongated body extending from the top surface of the substrate and incorporating at least one emitter tip on the distal end of the elongated body thereof. The emitters may be disposed on the substrate in an ordered array in an X by Y grid pattern, wherein X and Y can be any number greater than zero. The micro-emitter arrays may utilize a LMIS propellant source including, for example, gallium, indium, bismuth, or tin. The substrate may incorporate at least one through-via providing a fluid pathway for the LMIS propellant to flow from a propellant reservoir beneath the substrate to the top substrate surface whereupon the micro-emitter array is disposed.

Micro-emitters for electrospray systems

A diffractive optic sheer stress sensor operates by forming diverging fringes over a linear area of measurement. A diode laser focuses light onto a diffractive lens which focuses the light to respective slits. The slits form diverging fringes, and scattered light from the fringes is collected by a window and focused by another diffractive lens to a receiver.

Diffractive optical fluid shear stress sensor

The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for rapidly occurring events it is also useful for investigation of some slow moving phenomena as in the life sciences.

Computed tomography imaging spectrometer (CTIS) with 2D reflective grating for ultraviolet to long-wave infrared detection especially useful for surveying transient events

The present disclosure describes a technique for creating diffraction gratings on curved surfaces with electron beam lithography. The curved surface can act as an optical element to produce flat and aberration-free images in imaging spectrometers. In addition, the fabrication technique can modify the power structure of the grating orders so that there is more energy in the first order than for a typical grating. The inventors noticed that by using electron-beam lithography techniques, a variety of convex gratings that are well-suited to the requirements of imaging spectrometers can be manufactured.

Diffractive optical elements on non-flat substrates using electron beam lithography

An uncooled infrared tunneling sensor in which the only moving part is a diaphragm which is deflected into contact with a micromachined silicon tip electrode prepared by a novel lithographic process. Similarly prepared deflection electrodes employ electrostatic force to control the deflection of a silicon nitride, flat diaphragm membrane. The diaphragm exhibits a high resonant frequency which reduces the sensor's sensitivity to vibration. A high bandwidth feedback circuit controls the tunneling current by adjusting the deflection voltage to maintain a constant deflection of the membrane. The resulting infrared sensor can be miniaturized to pixel dimensions smaller than 100 .mu.m. An alternative embodiment is implemented using a corrugated membrane to permit large deflection without complicated clamping and high deflection voltages. The alternative embodiment also employs a pinhole aperture in a membrane to accommodate environmental temperature variation and a sealed chamber to eliminate environmental contamination of the tunneling electrodes and undesireable accoustic coupling to the sensor.

Uncooled tunneling infrared sensor

A method for producing a phase hologram using e-beam lithography provides n-ary levels of phase and amplitude by first producing an amplitude hologram on a transparent substrate by e-beam exposure of a resist over a film of metal by exposing n.ltoreq.m.times.m spots of an array of spots for each pixel, where the spots are randomly selected in proportion to the amplitude assigned to each pixel, and then after developing and etching the metal film producing a phase hologram by e-beam lithography using a low contrast resist, such as PMMA, and n-ary levels of low doses less than approximately 200 .mu.C/cm.sup.2 and preferably in the range of 20-200 .mu.C/cm.sup.2, and aggressive development using pure acetone for an empirically determined time (about 6 sec.) controlled to within 1/10 sec. to produce partial development of each pixel in proportion to the n-ary level of dose assigned to it.

Continuous phase and amplitude holographic elements

Growing community of inventors

Altadena, CA, United States of America

Richard E Muller