Interference fringes are registered by detectors. All detectors absorb energy from a single or multiple superposed fields through the process of “square modulus” of the sum of the complex amplitudes. The detected energy becomes proportional to the total relative phase difference for all the superposed fields. The process creates ambiguity in discerning the effects due to frequency and phase mod...

Time-delay interferometry (TDI) is a post-processing technique used to reduce laser noise in heterodyne interferometric measurements with unequal armlengths, situation characteristic of space gravitational detectors such as the Laser Interferometer Space Antenna (LISA). This consists properly time-shifting and linearly combining order by several orders magnitude detect waves. In this communicat...

We present three-dimensional (3-D) in vivo photoacoustic (PA) images of the blood vasculature of a chicken chorioallantoic membrane (CAM) obtained by using a fiber-based noncontact PA tomography system. With a fiber-optic heterodyne interferometer, the system measures the surface displacement of a sample, induced by the PA wave, which overcomes the disadvantage of physical-contact of ultrasonic...

A tangential viewing, 10.59 microm CO(2) laser polarimeter for electron density measurements based on plasma induced Faraday rotation has been installed on DIII-D. The system uses colinear right- and left-hand circularly polarized beams with a difference frequency of 40 MHz to generate the necessary signal for heterodyne phase detection. The high-resolution phase information required to adequat...

The sensitivity of 1-3 piezocomposites can be improved by the addition of a third phase or interlayer around the piezoceramic rods which results in a composite with 1-1-3 connectivity. In the current investigation, dynamic surface displacements of both 1-3 and 1-1-3 piezocomposites were measured using a laser Doppler heterodyne interferometer. Dynamic displacement profiles showing the nonunifor...

In this paper we present a novel technique for measuring the material properties of spherical objects. The technique is also capable of detecting the presence of surface defects in these objects. We excite resonances of spheres at both low and high frequencies. Resonances are generated by forming a one-point Hertzian contact between the sphere and a spherical depression in a buffer rod with a t...

A design is described for a transmitter/receiver system that may be used in a spaceborne laser heterodyne tracking system to produce a high-precision interferometer. We present a two-color laser scheme that enables accurate phase measurement even in the presence of a large Doppler offset between the incoming and outgoing signals. The beat note between the two lasers provides a built-in frequenc...

The absolute distance between the mirrors of a Fabry-Perot cavity with a spacer from an ultra low expansion material was measured by an ultra wide tunable laser diode. The DFB laser diode working at 1542 nm with 1.5 MHz linewidth and 2 nm tuning range has been suppressed with an unbalanced heterodyne fiber interferometer. The frequency noise of laser has been suppressed by 40 dB across the Four...

We present a detailed experimental and theoretical study of plasmon Talbot effect. A theoretical model based on simple scattering theory is developed to describe the Talbot self-imaging pattern generated by a linear arrangement of cylindrical nanostructures forming a periodic array. We first show the experimental observation of plasmon Talbot carpets created by propagating surface plasmon polar...

The effects of residual amplitude modulation (RAM) in laser interferometers using heterodyne sensing can be substantial and difficult to mitigate. In this work, we analyze the effects of RAM on a complex laser interferometer used for gravitational wave detection. The RAM introduces unwanted offsets in the cavity length signals and thereby shifts the operating point of the optical cavities from ...