A method for obtaining the average refractive indexes of a birefringent material in the terahertz region in a single measurement with a standard terahertz time-domain spectrometer is presented. The method is based on processing the frequency-domain interference between terahertz pulses and echoes through the Fourier transform of the terahertz spectrum. The technique also allows the determinatio...

We report the experimental observation of all-optical modulation of light in a graphene film. The graphene film is scanned across a standing wave formed by two counter-propagating laser beams in a Sagnac interferometer. Through a coherent absorption process the on-axis transmission is modulated with close to 80% efficiency. Furthermore, we observe modulation of the scattered energy by mapping t...

We demonstrate a reconfigurable optical filter implemented using a phase-only two-dimensional liquid-crystal-on-silicon spatial light modulator. To achieve this we utilize two different approaches leading to two different configurations in the modulator. The first one, based on a spatially patterned diffractive lens, permits us to obtain the desired spectrum along the optical axis and, in the s...

For most imaging cameras, it is desirable that the sensor plane be perpendicular to the optical axis. Such an orientation ensures that the imaging configuration is perspective and planar scene objects perpendicular to the optical axis can be focussed in their entirety. In this paper, we have presented an image processing based method to estimate and subsequently correct the sensor tilt with pre...

An improved temperature-insensitive optical voltage sensor (OVS) with a reciprocal dual-crystal sensing method is proposed. The inducing principle of OVS reciprocity degradation is expounded by taking the different temperature fields of two crystals and the axis-errors of optical components into consideration. The key parameters pertaining to the system reciprocity degeneration in the dual-crys...

The determination of the instantaneous axis of rotation of human joints has numerous applications. The screw axis can be determined using optical motion capture systems or electromechanical goniometers. In this paper, we introduce a new method for the localization of the instantaneous screw axis in human anatomical joints from the data given by a spatial mechanical goniometer.

Experimental validation of a distortion removal technique for multi-chip free-space optical shuffle interconnections is presented. The free-space fabric links dense two-dimensional arrays of vertical cavity surface emitting laser(s) (VCSEL)(s) and detectors and must achieve full field registration on the order of 10 microns across the entire array. The new hybrid micro-macro optical concept rea...

Monolithically cascaded one-axis micromirrors driven by angular vertical combs are designed and fabricated. Using "W"-shape ray optics, we demonstrate two-axis scanning covering k6.0' two-dimensional area at resonant modes: 7.5kHz, +I 7V in fast-scanning mirror, 1.2kHz, +7V in slow-scanning mirror. INTRODUCTION Because of their independently controllable scanning directions, cascaded one-axis l...