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We describe a new mode of optical lithography called absorbance-modulation optical lithography (AMOL) in which a thin film of photochromic material is placed on top of a conventional photoresist and illuminated simultaneously by a focal spot of wavelength lambda1 and a ring-shaped illumination of wavelength lambda2. The lambda1 radiation converts the(More)
High-numerical-aperture zone plates have important applications in high-resolution optical maskless lithography as well as scanning confocal microscopy. We describe two methods to experimentally characterize the focusing properties, i.e., the point-spread function, of such diffractive lenses. The first method uses spot exposures in photoresist and the(More)
In the past, the formation of microscale patterns in the far field by light has been diffractively limited in resolution to roughly half the wavelength of the radiation used. Here, we demonstrate lines with an average width of 36 nanometers (nm), about one-tenth the illuminating wavelength lambda1 = 325 nm, made by applying a film of thermally stable(More)
This paper demonstrates a model for electricity delivery and revenue collection in a rural context with the potential to increase the reliability of service delivery and lower operating costs compared to traditional fixed monthly fee utilities. The microutility in this paper provides power on a pre-paid basis similar to the way cellular phone air-time is(More)
In this Letter, we report the confinement of a uniform beam of light (lambda(1) = 400 nm) at the nodes of a standing wave (lambda(2) = 532 nm) via absorbance modulation. In the present implementation of absorbance modulation, a thin polymer film containing a photochromic azobenzene side chain is exposed to a standing wave at lambda(2) and a uniform beam at(More)
We present an extension of the direct-binary-search algorithm for designing high-efficiency multi-wavelength diffractive optics that reconstruct in the Fresnel domain. A fast computation method for solving the optimization problem is proposed. Examples of three-wavelength diffractive optics with over 90% diffraction efficiency are presented. These(More)
We experimentally verify the focusing characteristics of dichromats, a new class of circular-symmetric diffractive-optical lenses that generate, in the same focal plane, focal spots for one wavelength and ring-shaped spots with central nodes for another wavelength. Using a dichromat, we illuminate a thin photochromic layer and demonstrated(More)
A kinetic model describing the conversion of a photochromic layer under complex illumination conditions is applied to absorbance-modulation optical lithography to determine the influence of the material characteristics on the confinement to subdiffraction dimensions of the transmitted dose. We show that the most important parameters are the intensity ratio(More)
Absorbance modulation is an approach that enables the localization of light to deep sub-wavelength dimensions by the use of photochromic materials. In this article, we demonstrate the application of absorbance modulation on a transparent (quartz) substrate, which enables patterning of isolated lines of width 60 nm for an exposure wavelength of 325 nm.(More)
Earlier we reported on a proof-of-concept maskless-lithography system that used an array of Fresnel zone plates to focus multiple beams of 442 nm light onto a substrate, and micromechanics for multiplexing light to the several zone plates, enabling patterns of arbitrary geometry, at 350 nm linewidth, to be written. We referred to the technique as(More)