<B>Abstract:</B>

Historically, THz applications have focused mainly on the identification and mapping of lightweight gases and molecules present in the cold, low-pressure environments in and around regions of star formation, gas and dust in the galaxy, the atmospheres of planets and small solar system bodies (moons and comets), and the upper atmosphere of the Earth. In recent times, especially after the advent of THz pulsed time domain spectroscopy, applications of this far infrared wavelength regime have spread into many new areas of technology. Most prescient is the recent interest in THz imaging and spectroscopy for security screening applications. The largest commercial driver for sub-THz however, is likely to be in communications, and if early trends continue, we will all be seeing dramatic increases in the amount of RF radiation omnipresent in our local environment. Especially apropos is the high power density, millimeter-wave crowd-control system known as active-denial. For these reasons, careful evaluation of the impact of millimeter and submillimeter wavelength radiation on biological systems is sorely needed.

In this talk we will focus on some recent work at Caltech in conjunction with partners at the Huntington Medical Research Institute in Pasadena, on the interaction of millimeter-waves with cells and cell function. Our most recent results involve direct patch clamp monitoring of mouse pup cortical brain slices under very low level millimeter-wave exposure (1,000 times lower than the prescribed safe limit). We have recorded both inhibition and enhancement of action potential firing rates in individual neurons and controllable neuronal membrane depolarization. This may have applications in non contact pain suppression, drug delivery and activation of neural prosthetics.