Design of Gradient Index Optical Thin Films

Gradient index thin films provide greater flexibility for the design of optical coatings than the more conventional \u27layer\u27 films. In addition, gradient index films have higher damage thresholds and better adhesion properties. This dissertation presents an enhancement to the existing inverse Fourier transform gradient index design method, and develops a new optimal design method for gradient index films using a generalized Fourier series approach. The inverse Fourier transform method is modified to include use of the phase of the index profile as a variable in rugate filter design. Use of an optimal phase function in Fourier-based filter designs reduces the product of index contrast and thickness for desired reflectance spectra. The shape of the reflectance spectrum is recovered with greater fidelity by suppression of Gibbs oscillations and shifting of side-lobes into desired wavelength regions. A new method of gradient index thin film design using generalized Fourier series extends the domain of problems for which gradient index solutions can be found. The method is analogous to existing techniques for layer based coating design, but adds the flexibility of gradient index films. A subset of the coefficients of a generalized Fourier series representation of the gradient index of refraction profile are used as variables in a nonlinear constrained optimization formulation. The optimal values of the design coefficients are determined using a sequential quadratic programming algorithm. This method is particularly well suited for the design of coatings for laser applications, where only a few widely separated wavelength requirements exist. The generalized Fourier series method is extended to determine the minimum film thickness needed, as well as the index of refraction profile for the optimal film

Optical Phase Conjugation Via Stimulated Brillouin Scattering in a Brillouin Ring Laser

Stimulated Brillouin scattering (SBS) was demonstrated in multimode optical fiber using a Brillouin ring laser configuration. The frequency shift of the SBS generated output beam was measured at 33.1 GHz. Pump laser power thresholds for SBS onset were determined for several ring cavity configurations and compared to theoretical values. optical phase conjugating properties of SBS in multimode optical fiber were investigated. No phase conjugation of an aberrated pump beam was evident in the Brillouin ring laser output

Optimal phase function for gradient-index optical filters

Fourier transform techniques for design of gradient-index optics have previously used arbitrary forms for the complex part of the reflectance profile.</jats:p

Novel Use of a One-stage Synthetic Dermal Substitute for the Treatment of a Class III Ring Avulsion Injury

We present a novel treatment of an Urbaniak class III ring avulsion injury using the application of one-stage synthetic dermal substitute. Ring avulsion injuries are uncommon and complicated injuries despite the small forces needed to produce a complete amputation. Most often the treatment involves an emergent trip to the operating room for revision amputation or salvage procedures including replantation. We illustrate and describe the treatment of a class III Urbaniak ring avulsion injury with application of one-stage synthetic dermal substitute. A review of the current literature, a description of the patients’ operative management, and a 1-year follow-up are provided

Optimum Phase for Thin Film Synthesis by Fourier Transforms

An optimum phase is developed for rugate reflector design by a simple Fourier Transformation. Surprisingly good solutions are obtained for arbitrary spectral curves by phase shaping alone.Peer reviewed: YesNRC publication: Ye