This experiment investigates properties of light at the single photon level. We generate pairs of 915.8-nm photons through parametric downconversion by sending a beam of 457.9-nm light through a BBO crystal. These downconverted photons are detected using two avalanche photodiodes. We then create a distinguishable characteristic in one arm of a Mach-Zehnder interferometer by adding a half wavepl...

We introduce an interferometric interpretation for the degree of polarization as a quantity characterizing the ability of a light beam to generate polarization modulation when it interferes with itself. The result is confirmed experimentally in Youngʼs interferometer with beams of controlled degree of polarization and by comparing to a standard polarimetric measurement. The new interpretation i...

A hyperspectral Fourier transform spectrometer has been developed for studying biological material bound to optically reflecting surfaces. This instrument has two modes of operation: a white-light reflection mode and a spectral self-interference fluorescence mode. With the combined capability, information about the conformation of an ensemble of biomolecules may be determined. To the best of ou...

An experimental study is conducted to show the effect of the change in bandwidth of light on the spectral degree of coherence at a pair of points in the cross section of a beam. For this purpose a polychromatic source and a monochromator with variable entrance and exit slits were used to produce a variable bandwidth source. The classic Young's interferometer was used to produce an interference ...

We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial position displays complex behavior with regions of positive and negative interference. By analyzi...

The optical absorption of nanoscale thickness semiconductor films on top of light-trapping structures based on optical interference effects combined with spectrum-splitting structures is theoretically investigated. Nearly perfect absorption over a broad spectrum range can be achieved in <100 nm thick films on top of a one-dimensional photonic crystal or metal films. This phenomenon can be attri...

Taking recent experiments as examples, we discuss the conditions for sub-wavelength probing of optical field structures by single trapped atoms. We calculate the achievable resolution, highlighting its connection to the fringe visibility in an interference experiment. We show that seemingly different physical pictures, such as spatial averaging, phase modulation, and which-way information, desc...

Due to the massive insertion of embedded cameras in a wide variety of devices and the generalized use of LED lamps, Optical Camera Communication (OCC) has been proposed as a practical solution for future Internet of Things (IoT) and smart cities applications. Influence of mobility, weather conditions, solar radiation interference, and external light sources over Visible Light Communication (VLC...

We present a study of the imaging of the interference of spatial-helical modes of single photons. This work includes a mathematical treatment that accounts for the direction of propagation and spatial mode degrees of freedom in the situation where light travels through an interferometer that prepares the light in distinct spatial modes and makes them interfere. We present results of the interfe...

It is shown how surface plasmons that travel between the slits in Young's interference experiment can change the state of spatial coherence of the field that is radiated by the two apertures. Surprisingly, the coherence can both be increased and decreased, depending on the slit separation distance. This results in a modulation of the visibility of the interference fringes. Since many properties...