The most general model of elliptical birefringence in an optical fiber is extended to describe a transient Brillouin interaction including both gain and loss. The effects of elliptical birefringence cause a Brillouin spectral shape distortion, which is detrimental for fiber sensing techniques. The model investigates the effects of birefringence and the corresponding evolution of spectral distortion effects along the fiber, and also investigates regimes where this distortion is minimal.

Based on the photothermal detuning technique, the three linear relations among reflectance (or transmittance), temperature rise, and pump beam power are studied to achieve the absolute measurement of absorption loss. The relation between temperature and reflectance and the calculation accuracy of temperature rise on sample surface have great impacts on the measured result. The influences of parameters involved in the method and the relation between temperature and reflectance and the temperature model of sample surface are also studied. The results show that the absolute absorption loss of optical coatings can be achieved by the proposed method. The measurement accuracy depends on the temperature model and the relation between temperature and reflectance. The linear relation between reflectance and temperature rise has largest slope when probe beam wavelength is 632.8 nm and incident angle is 28o. The linear relation slope between temperature rise and pump beam power decreases with the growing of beam size and modulation frequency. The results provide theoretical and experimental supports for the perfection and further application of the photothermal detuning technique.

TiO2 chiral sculptured thin films (CSTFs) prepared using glancing angle deposition (GLAD) method based on electron beam evaporation are studied. The relationship between structural parameters and circular Bragg phenomenon (CBP) is investigated. Results demonstrate that, the central wavelength of Bragg regime red-shifts with the increasing pitch of helix, and peak value of selective transmittance will increase after adding more turns to the helix. After annealing, the central wavelength blue-shifts and the peak value rises. Tuning CBP by modulating the deposition parameters and annealing can optimize the performance of circularly polarized devices fabricated from CSTFs.

Fulgide, a kind of thermally irreversible photochromic compound, can be used for polarization holographic recording owing to its photoinduced anisotropy and photochromic property under the irradiation of linear polarization light. In this letter, a new technique of optical image operation based on the polarization multiplexing scheme in the fulgide film is demonstrated, which can implement the readout of two individual orthogonal polarized images separately and the subtraction or summation of the two images by simply rotating a polarizer in front of the charge-coupled device (CCD) detector.

Diffraction efficiency of volume Bragg grating, whose period is in the same order as the incident wavelength, is related to the polarization direction of the incident linear polarized beam. When two linearly polarized recording beams with the same polarization direction are used for recording volume Bragg gratings in a photopolymer with diffusion amplification, the azimuth of polarization of the reconstruction beam influences the diffraction efficiency of the grating. When the probe beam is linearly polarized and oriented orthogonally to the grating vectors, the ±1-order diffraction beams are also linearly polarized with polarization direction parallel to that of the probe beam. According to the results, a two-dimensional nonspatial optical filter consisting of the volume Bragg gratings would achieve significantly higher efficiency.

An explicit model from the matrix method is utilized to describe the measurement sensitivity of the photothermal detuning technique dependent on the polarization of the probe beam. Numerical results show that the optimal probe wavelengths and the slope of the main spectral band edges are different for both s- and p-polarized beams with the same incident angle. Compared with the random polarized probe beam at the larger incident angle, the measurement sensitivity can be improved approximately twice over with the p- and s-polarized probe beams under the optimal condition.

Multilayer dielectric thin films have polarization effects at non-normal incidence. In this letter, specifications include s- and p-polarization transmittance (Ts,(p) ≥ 95% at 790—808 nm), s- and p-polarization reflectance (Rs,(p) ≥ 95% at 814—860 nm), angle of incidence (AOI) = 45°, air as incident medium, and BK7 glass as substrate. Based on the two chosen materials (Ta2O5 and SiO2), non-polarized edge filters are carried out using the design methods of the detuned multiple half-wave filters (exact design) and the needle optimization (numerical design). Exact design has a total of 112 layers and 12 cavities; optical thickness is 126 quartwaves at 860 nm. Numerical design has a total of 107 layers and 8 cavities; optical thickness is 91 quartwaves at 850 nm. Hence, the numerical design has less layers and thickness, thus meeting the same specifications of the exact design.

We study the sensing properties of an intensity-modulated fiber-optic surface plasmon resonance (SPR) sensor using radially polarized beam (RPB). Because of the rotational symmetry of fiber and RPB, surface plasmon can be excited more efficiently at the sensor surface, which results in an obvious improvement of the sensitivity. Our experiments demonstrate that the sensitivity in the case of RPB illumination is three times higher than that of linearly polarized beam illumination.