Massachusetts Institute of Technology

Stephen T Palmacci

Roderick Russell Kunz

Theodore M Bloomstein

Sumanth Kaushik

Charles Wynn

Robert W Haupt

A kit for detecting the presence of an explosive includes a pulsed focused energy source located at a target distance away from a substrate, the energy having a magnitude sufficient to release the internal energy of an explosive if present on the substrate and thereby generate an acoustic wave. The kit also includes a detector adapted to detect the acoustic wave at a detection distance away from the substrate.

Method and kit for stand-off detection of explosives

Methods for the preparation of multilayered resists are described. To efficiently pattern large contiguous areas rapidly, a procedure has been developed using spot-size modulation of the focused laser beam to more efficiently pattern interior portions. Critical portions at the perimeter are patterned at high resolutions. The spot-size is progressively increased towards the interior allowing a controlled transition to coarser spot-sizes without impacting the exposure dose in critical portions. Patterning times are significantly reduced since in effect shells are patterned. An algorithm is defined to subdivide a layer into different zones, determine the appropriate focused spot-sizes used for each zone, and define the laser scan trace within a zone to enable efficient patterning of broad areas in positive tone resists.

Stereolithographic patterning with variable size exposure areas

Methods for the preparation of multilayered resists are described. A first layer of photoresist is deposited onto a substrate. First portions of the first layer are exposed to a first dose of radiant energy. A second layer of photoresist is deposited at atop the first layer and second portions of the second layer are exposed to a second varied dose of radiant energy. The dose is modulated over different portions of a layer to preferentially enhance development within the interior of the structure to reduce total development times.

Stereolithographic patterning by variable dose light delivery

Methods for the preparation of multilayered resists include exposure of the a first layer to radiation followed by exposure to an oxidizing agent. The oxidizing agent alters the surface characteristics of the first resist layer such that it is rendered more hydrophilic than the original resist layer. A second layer of resist is then applied to the oxidized surface of the first resist layer and exposed to radiation. This process can be repeated for thousands of coating layers, thereby permitting stereolithographic patterning of parts and construction of micromachines. A final treatment with a dissolution solution will dissolve unwanted resist material. Dependent upon the type of resist material used in the multilayered resist, the dissolution solution can remove the radiation exposed areas, e.g., a positive resist, or remove unexposed areas, e.g., a negative resist.

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Arlington, MA, United States of America

Stephen T Palmacci