Undergraduate Research & Mentoring Program

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Three-dimensional printing -- Applications to optical imaging systems, Terahertz spectroscopy, Terahertz technology


The terahertz gap in the electromagnetic spectrum provides promising advantages for applications such as increased airport security and medical diagnosis. Quasi-optical systems used to study THz radiation require multiple mirrors or lenses, which can be quite costly. In order to manipulate THz beams we investigated production of inexpensive lenses using additive 3D printing. 3D printing technology promises to be not only accessible and inexpensive, but should also enable quick experimentation with different lens designs. The Picometrix time-domain spectroscopy (TDS) system was used to characterize 3D printable plastics. The absorption coefficient and refractive index were analyzed from 0.2 to 2 THz to determine the most suitable candidate for lens application. Polypropylene (PP) exhibited low power loss within the sub-THz band and is easy to print. Three plano-convex spherical lenses were designed using a CAD software (Onshape) and were manufactured by ProtoArc’s Hub. Lenses were tested using a VNA system at 150 GHz. Gaussian beam analysis was used to determine the focal length of the lens f = 7.5 in. Our initial results indicate that it is feasible to produce good quality lenses out of Polypropylene using 3D printing. Future work will characterize lenses more fully and explore additional materials and lens designs.


Image of the E-field Amplitude vs Radius (5.75in from Lens to Horn) is included in the Additional Files below.

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5p75in v2.png (87 kB)