Total Internal Reflection Phase Research Articles

Problems in Polarization Metrology

Polarization metrology is gaining increased importance as polarized light is recently involved in different branches of science and technology. This paper summarizes the contributions of the optical polarization laboratory at the National Institute for standards (NIS, Egypt) during the last 25 years. These include introducing a new class of total internal reflection phase retarders, modifying the Senarmont method to allow for simultaneous calibration of two phase plates at any wavelength, birefringence measurements, applications of the Poincare sphere, calibration and adjustment of polarization elements and measurements of the optical constants of conductors.

Polarizing phase shifting interferometry of total internal reflection light for measurement of refractive index and its spatial variation in liquid samples

It is well known that the phase change in total internal reflection (TIR) is a function of the refractive indices of the pair of media involved. The spatial phase variations in a totally internally reflected beam are accurately measured using a Mach Zehnder interferometer employing polarization phase shifting technique. The evaluated phase change is then related to the refractive index variations of the rarer medium. One of the salient features of the proposed technique is that, unlike most interferometric methods where the measured phase is a function of the sample thickness, TIR phase is independent of the sample thickness as long as the evanescent wave field is fully confined within the sample. The theory of the technique is discussed and experimental results showing the three-dimensional profiles of the measured refractive indices and its spatial variations are presented.

Optical distortions in end-pumped zigzag slab lasers

Ray tracing is performed to investigate the optical distortions in the end-pumped, zigzag slab. Optical path differences caused by temperature, slab deformation, and stress birefringence are calculated under uniform pumping; the results show a steep edge in the width dimension and a thermal lens with an effective focal length as short as several meters in the thickness dimension. Dependence of depolarization on total internal reflection phase retardance as well as the slab's cut angle is studied by the Jones matrix technique; results show that although at the pumping power of 10 kW, the mean depolarization of the 2.5 mm×30 mm×150.2 mm Nd:YAG slab is generally below 3%, and it increases rapidly with pumping power. Besides, for the 0°- or 60°-cut slab, an optimal phase retardance range of 5° to 13° exists, in which the depolarization loss can be lower than 0.5%. Finally, experiments on temperature and depolarization measurements verify the numerical results.

Total internal reflection phase retarders constructed from prisms

It is shown that the known rhomb-type total internal reflection phase retarders could be constructed from prisms. With all the advantages of the traditional designs preserved, these prism-type devices are of smaller volumes, convenient shapes, and light traverses shorter path lengths inside the devices. Moreover, the serious reduction in the volumes of the presented devices reduces the undesired stress birefringence which affects the retardance value. Two cases will be considered, which are the 4-reflection normal-incidence AD-1 and the super achromatic 2-reflection oblique-incidence quarter-wave phase retarders.

Phase retarders highly insensitive to the input angle

In the few exceptional cases of total internal reflection phase retarders that are weakly sensitive to variations in the input angle of incidence i, the devices are of increasingly larger size; deviate or translate the emergent beam; are difficult to align in optical systems; or, in coated rhombs, have an impermanent stability of the retardance. Based on new compensating effects, novel devices of high retardance stability and advantageous characteristics are presented. One device is stable to within 0.09 degrees of 90 degrees for i ? 3 degrees . It is a two-reflection quarter-wave retarder that does not alter the path of the compact size light beam, is of compact size (one seventh the size occupied by the achromatic device AD-1 for equal aperture lengths), and can be easily aligned in optical systems or used as a rotating element. The path length of the beam inside the device is less than one third the corresponding length inside the achromatic device AD-1.

Silicon-based polarization optics for the 1.30 and 1.55 μm communication wavelengths

A modular three-reflection prism of Si can be designed to function as an in-line (nondeviating) linear polarizer or quarterwave retarder at the 1.30 and 1.55 /spl mu/m lightwave communication wavelengths. Si-related thin films are employed as optical coatings. In particular, a single-layer antireflection coating of Si/sub 3/N/sub 4/ is used at the entrance and exit faces, and a SiO/sub 2/ film controls the polarization and total internal reflection phase shifts at the side surfaces of the prism. The angular and wavelength sensitivity of these proposed Si-based polarization optical elements is also considered.

Analytical relations for thin-film total internal reflection phase retarders

Single-layer coatings on total internal reflection boundaries that produce any specific phase retardation are analyzed. One- and two-reflection phase-retarding systems are considered. Simple quadratic equations are obtained for an unknown layer phase thickness at a given angle of incidence and phase retardation. Equations for specific multilayer coatings that are equivalent to single-layer designs are also deduced. Diagrams of solution zones for refractive indices are given comparatively for one- and two-reflection systems.

Phase retarders with variable angles of total internal reflection

Results for three λ/4 phase retarders are reported. One of them is achromatic to within ± 0.06° of 90° in the visible region. It is shown that, under certain conditions, oblique incidence on the entrance face of total internal reflection phase retarders can greatly improve the achromaticity.

Bistability and optical switching in a total internal reflection phase conjugator

We report the observation of bistability in a BaTiO(3) total internal reflection phase conjugator. The system makes use of the position of the crystal relative to the input field as the dynamic variable. Switching behavior, induced by intensity changes at the input, is also reported.

Graphical method to design internal reflection phase retarders

Total internal reflection (TIR) results when light is reflected from a rare-to-dense interface between two dielectric media at an angle that exceeds the critical angle. The phase retardance, which is the difference between the TIR phase changes for the two planes of polarization, is a function of the refractive indices of the media and the incident angle. The addition of a transparent thin-film multilayer coating may be used to change the phase retardance of the interface to a value appropriate for a specific application. A graph of phase retardance D vs the average phase shift A as a function of layer thickness provides a means for visualization that is useful in the design process. The D–A graph predicts the phase properties of a coated TIR interface as a function of index and thickness of an added layer. Graphs of phase retardance vs average phase change for two or more different materials may be superposed to predict the phase performance of a multilayer coating. This graphical technique is employed to analyze and design several coatings.