He worked at the Aerospace Corporation as a technical staff member from February 1990 to May 1990 and became a Fellow of the American Physical Society in 1990.

[5] In February 2009, he was issued a patent from a filing in March 2002 for Detecting and/or Measuring Substance based on Resonance Shifts (of Photons Orbiting within a Microsphere).

[1] Arnold's research has focused on label-free detection of bio-nanoparticles from the perturbation of the resonant frequency of a microcavity, after estimating the extreme sensitivity of such an approach for DNA sensing in a 2001 American Scientist article.

[8] The recipe for the detection and sizing of single HIV viruses following this mechanism was proposed early in 2008 at a Faraday Discussion of the Royal Society of Chemistry.

Shopova that gold nano-receptors on the microcavity lead to a further frequency shift enhancement led to another patent issued in 2013, from a filing in 2011.

[14] This hybrid sensor uses gold nano-antennas on a small glass sphere to detect single ultra-small virus particles as well as individual proteins.