A total internal reflection device using KTN

A total internal reflection diffraction device has been constructed using a quadratic electro-optic material (KTN). This device exhibits a best zero order extinction voltage of 40 V, and a capacitance of 630 pf at room temperature (20° C above Curie temperature). Useful modulation is achieved with coarse gratings (0.4 mm pitch at 0.63m) and mildly striated material can often be used.     

Electrooptic waveguide switch using total internal reflection

An optical switching experinteml Based; ob the electrooptic control of total internal reflection of light in a Ti/LiNbO₃ planar waveguide is reported The device uses a refractive index gap, formed by only applying a voltage The operating principles and characteristics are discussed. The dependence of the switching efficiency on the mode depth is investigated in detail.     

受抑全反射的微波实验研究

首先回顾了受抑全反射的历史背景和广泛的应用价值,然后分析了受抑全反射的理论机制,得到相应的倏逝波透射率公式;并且建立了一套简单的实验装置系统,研究了受抑全内反射(FTIR)的透射率和空气薄膜厚度、偏振方向之间的关系.所得结果和理论分析符合的很好.     

Three-dimensional total internal reflection microscopy

We investigate the inverse-scattering problem that arises in total internal reflection microscopy. An analytic solution to this problem within the weak-scattering approximation is used to develop a novel form of three-dimensional microscopy with subwavelength resolution.     

Frustrated total internal reflection evanescent switching

The mechanism of frustrated total internal reflection was analyzed according to the theory of optical film. The transmission and reflection functions were developed and the curves of transmission and reflection changing from the relative gap width d/λ, incident angle θ₀, and refraction index n were shown in graphs. We proposed a scheme of experimental device to test the theoretical conclusion. A self-made electronic actuator drove the piezoelectric ceramics of FTIR. Experiments showed that the evanescent of transmission is 80% for He–Ne laser and smaller for YAG laser and Er:glass laser.     

Low voltage electro-optic polymer light modulator using attenuated total internal reflection

An improved electro-optic (EO) polymer light modulator based on attenuated-total-internal-reflection (ATR) is demonstrated. The modulator consists of a prism–metal–EO-polymer–metal multilayer structure. An applied electric field across the EO polymer layer electrically modulates the energy coupling efficiency of incoming light into guided wave resonance at fixed angles. Compared with conventional ATR modulators based on surface plasmon resonance, the driving voltage for this modulator has been greatly reduced because of the newly chosen working interior angle. It also offers advantages in terms of insertion loss and aperture size over other techniques for the amplitude modulation of a collimated light beam.     

Measurement of apex angle of the prism using total internal reflection

Total internal reflection technique is examined critically for the measurement of apex angle of the prism. Recognition of the critical boundary completely specifies the apex angle ‘A’ of the prism by keeping constant the ratio of refractive index of sample fluid (n₁=1.4) to that of glass (n₂=1.7). Recording of observations in the laboratory is dependent upon whether the apex angle ‘A’ of prism is greater than or less than or equal to critical angle ‘r_c’. The minimum value of error function ‘χ’ in the proximity of Abbe angle explain the choice of Abbe type instruments and shown invariant by relating positive ‘₊’ and the negative angle of emergence ‘₋’. Using ray-tracing technique, an expression for the length of the critical boundary ‘l’ is derived and is shown as a measure of the apex angle ‘A’ of the prism.

The choice of the realistic grazing condition leads us to two turning points for which error function ‘χ’ is minimal and yields appropriate option of the measurement of apex angle ‘A’ of the prism. It is further shown that the small error ‘ζ’ crept in the apex angle ‘A’ of the prism can lead to a significant error in the design of Pulfrich type instruments.

Experimental measurements are in-line with the predictions made.     

Spectroscopic studies of sorbing fibers using combined elements with multiple attenuated total internal reflection

Spectroscopic studies of sorbing devices on the basis of silica capillaries coated by sorbing polymer films are carried out by methods of spectroscopy of multiple attenuated total internal reflection with the use of combined elements of internal reflection. A technique for inspecting and improving the technological process of manufacture of sorbing devices for solid-phase microextraction and subsequent chromatographic analysis of organic compounds is developed.     

Effects of using a metal layer in total internal reflection fluorescence microscopy

This proceeding examines the characteristics of imaging through a metal-coated glass cover slip using total internal reflection fluorescence microscopy (TIRFM). Through back and front focal plane imaging of sub-diffraction-limited fluorescent beads, the experimental characteristics of the emission are compared with theoretical simulations. Furthermore, at the angle at which surface plasmon resonance occurs, we show that the anisotropic emission of the fluorescent beads collected through the metal layer results in a irregular point spread function that has a donut-like structure with multiple concentric rings. PACS 42.30.Va; 73.20.Mf     

Nonlinear total internal reflection of electromagnetic waves

We study the stationary solution of an unstable system of interacting inhomogeneous electromagnetic waves and an acoustic wave. It is shown that the instability of this system is of hard type and the threshold of its vanishing is smaller than the excitation threshold. When the amplitude of the incident wave exceeds the threshold value there occurs interaction with partial nonlinear layer transmission, which is changed by large reflection for a large wave amplitude. In this case, the total reflection in the direction opposite to the incident wave and in the specular direction can be greater than in the absence of interaction. A parameter region in which the backward reflection dominates the specular reflection is shown. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 9, pp. 1132–1143, September, 1997.     

Resonant tunneling in frustrated total internal reflection

Anomalous light transmission and resonant tunneling in frustrated total internal reflection (FTIR) are theoretically predicted to occur at periodically curved interfaces. For a low-contrast index and for grazing incidence, it is shown that FTIR resonant tunneling provides an optical realization of field-induced barrier transparency in quantum tunneling.     

Comparison of Yb-doped fiber laser with one-end and double-end pumping configuration

A high-power Ytterbium-doped fiber laser (YDFL) with homemade double clad fiber (DCF) is introduced in this paper. The output power characteristics of a linear cavity fiber laser have been studied theoretically by solving the rate equations and experimentally tested with single- and double-end-pumping configurations. When both ends of the fiber are pumped by two high-power laser diodes with a launched power of 300 W each, a maximum CW output of 444 W is obtained with a slope efficiency of 75%.     

Evaluation of light scattering in attenuated total reflection configuration

A theoretical investigation of light scattering in first-order Born approximation in order to analyse the different scattering sources is presented for the case of the so-called Kretschmann attenuated total reflection (ATR) configuration. This three-layer system consists of a high permittivity superstrate acting as a prism, a thin metallic layer and air as substrate. The interesting aspect of this system is the occurrence of a resonance for both the exciting and the scattered light caused by surface plasmon polaritons (SPPs) at the metal-air interface. The scattered light will be calculated under the assumption of different illumination and detection conditions. The scattering contributions are assumed to be caused by the roughness of both interfaces and the volume inhomogeneities in the metallic layer. The calculated curves show the principal possibility of analysing the different scattering sources by an appropriate experimental strategy.     

High power 1.57-μm OPO pumped by MOPA with SBS

A Nd:YAG master oscillator power amplifier (MOPA) system, pumped by a pulse flash-lamps as the pump source of optical parametric oscillator (OPO), is employed to improve the pump beam quality of OPO pump source. A back amplifying configuration with stimulated Brillouin scattering (SBS) phase conjugation mirror is used. OPO pump laser energy of 611 mJ/pulse with 30-ns pulse duration is obtained, and near diffraction limited beam quality is achieved. Based on the type Ⅱ degenerate non-critically phase-matched KTP crystal, the OPO is used to convert pump beam from 1.064μm to 1.57μm, eye-safe near infrared laser range source. 1.57-μm output energy of 209 mJ/pulse with 18-ns pulse duration is attained with a short cavity KTP OPO, when pump laser energy is approximately 611 mJ. OPO conversion efficiency is up to 38.7% when pump laser energy is approximately 200 mJ.     

Structured illumination in total internal reflection fluorescence microscopy using a spatial light modulator

In wide-field fluorescence microscopy, illuminating the specimen with evanescent standing waves increases lateral resolution more than twofold. We report a versatile setup for standing-wave illumination in total internal reflection fluorescence microscopy. An adjustable diffraction grating written on a phase-only spatial light modulator controls the illumination field. Selecting appropriate diffraction orders and displaying a sheared (tilted) diffraction grating allows one to tune the penetration depth in very fine steps. The setup achieves 91 nm lateral resolution for green emission.