Article

Femtosecond laser fabrication of tubular waveguides in poly(methyl methacrylate).

School of Optics and Center for Research and Education in Optics and Lasers, University of Central Florida, Orlando, Florida 32816, USA.
Optics Letters (Impact Factor: 3.39). 09/2004; 29(16):1840-2. DOI: 10.1364/OL.29.001840
Source: PubMed

ABSTRACT Femtosecond laser direct writing is employed for the fabrication of buried tubular waveguides in bulk poly(methyl methacrylate). A novel technique using selective chemical etching is presented to resolve the two-dimensional refractive-index profile of the fabrication structures. End-to-end coupling in the waveguides reveals a near-field intensity distribution that results from the superimposition of several propagating modes with different azimuthal symmetries. Mode analysis of the tubular waveguides is performed using the finite-difference method, and the possible propagating mode profiles are compared with the experimental data.

0 Bookmarks
 · 
97 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Maskless laser direct writing lithography has been applied in the fabrication of optical elements and electric-optical devices. With the development of technology, the feature size of the elements and devices is required to reduce down to nanoscale. Increasing the numerical aperture of converging lens and shortening the laser wavelength are good methods to obtain the small spot and reduce the feature size to nanoscale, while this will cause the reduction of the depth of focus. The reduction of depth of focus will lead to some difficulties in the focusing and tracking servo controlling during the high speed laser direct writing lithography. In this work, the combination of the diffractive optical elements and the nonlinear absorption inorganic resist thin films cannot only extend the depth of focus, but also reduce the feature size of the lithographic marks down to nanoscale. By using the five-zone annular phase-only binary pupil filter as the diffractive optical elements and AgInSbTe as the nonlinear absorption inorganic resist thin film, the depth of focus cannot only extend to 7.39 times that of the focused spot, but also reduce the lithographic feature size down to 54.6 nm. The ill-effect of sidelobe on the lithography is also eliminated by the nonlinear reverse saturable absorption and the phase change threshold lithographic characteristics.
    Optics Communications 09/2013; 304:49–53. · 1.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The evanescently coupled multicore waveguide lattice composed of 37 linear type I cores hexagonally arranged has been theoretically studied and fabricated by low-repetition-rate femtosecond laser inscription of bulk fused silica. The effects of the single core's numerical apertures (NAs) and spacing on the mode characteristics of the 37-core waveguide were calculated by the finite-element method. It was found that the mode field areas of the fundamental mode LP<sub>01</sub> with 5 μm spacing of different NAs were all larger than 577 μm<sup>2</sup>, which was confirmed by the experiments. The measured near-field mode profiles for different writing conditions and different spacing also showed that the waveguide supported both a single mode (LP<sub>01</sub>) and two modes (LP<sub>01</sub> and LP<sub>11</sub>). The multicore waveguide, according to our study, is particularly interesting for mode converters.
    Applied Optics 11/2013; 52(33):7981-6. · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report results of a systematic study of the morphology of laser-written structures within transparent media like fused silica, borosilicate glass (BK7), and polymethylmethylacrylate (PMMA) using a high-energy, 5.1 MHz repetition rate, femtosecond laser oscillator. Depending on experimental conditions, both smooth channels as well as dot patterns can be laser-written. The periodicity of the written dots is readily controlled by the energy dose, a single parameter that encompasses laser energy, translation speed at fixed repetition rate, and focusing conditions. We discover the importance of the direction in which laser-writing is carried out: the periodicity of the dot patterns written at fixed energy dose but with opposite writing directions is significantly different. In PMMA, extremely large rod-like structures (∼200 µm) are observed whose formation is also dependent on writing direction. We quantify guidance of 632 nm and 830 nm light in structures written in BK7
    Optics Communications 09/2013; 304. · 1.44 Impact Factor

Full-text (2 Sources)

View
5 Downloads
Available from
Jun 10, 2014