Yu. V. Miklyaev

Three-dimensional face-centered-cubic photonic crystal templates by laser holography: fabrication, optical characterization, and band-structure calculations

We fabricate three-dimensional photoresist templates by means of laser holography. In particular, fcc structures are achieved by placing a specially designed “prism” onto the photoresist surface. This solves the problem of previous work, in which the refraction at the air–photoresist interface made it impossible to obtain the required angles of the light wave vectors inside the photoresist. The photoresist templates are characterized by scanning electron microscopy as well as by optical transmission spectroscopy, which agree well with numerical band-structure calculations.

One-dimensional photonic crystal based on nanocomposite of metal nanoparticles and dielectric

One-dimensional photonic crystal made of nanocomposite of metallic nanoparticles and dielectric is investigated. Splitting of photonic band gap into polaritonic and structure band gap and their fusion are predicted. The different behavior of structure gap with variation of nanoparticle concentration is observed. This behavior is determined by relative arrangement of structure and polaritonic gaps in frequency scale. Considered effects give new possibilities for creating photonic crystals with predefined properties.

Band structure calculations of 2D photonic pseudoquasicrystals obtainable by holographic lithography

The most interesting phenomena in photonic crystals stipulate the presence of omnidirectional band gap, i.e. overlapping of stop bands in all directions. Higher rotational symmetry and isotropy of quasicrystals in comparison with ordinary crystal give a hope to achieve a gap opening at lower dielectric contrasts. But nonperiodic nature of quasicrystals makes the size of stop bands lower than in the case of ordinary periodic crystal. We study transition from periodic structure to nonperiodic one by considering pseudoquasicrystals - quasicrystal approximants with growing period to weigh advantages and disadvantages of quasicrystals. We consider the structures that can be obtained by multiple exposure holographic lithography for the case of 2, 3, 4, and 6-fold exposure by two wave interference pattern, corresponding square, hexagonal, 8-fold and 12-fold symmetry lattice.

Superresolution microscopy in far-field by near-field optical random mapping nanoscopy

Obtaining an optical resolution of better than 200 nm requires rather slow and complicated techniques such as near-filed scanning optical microscopy. Here, we demonstrate a method of optical near-field acquisition by far-field microscopy—near-field optical random mapping nanoscopy. An object surface is randomly scanned by nanoparticles undergoing Brownian motion. The resolution of the method is restricted only by the size of observable nanoparticles (as small as 10 nm). We have achieved a resolution of 96 nm by using an objective with NA = 0.4. Thus, the resolution of the given far-field microscope is improved in more than six times.

Efficient diffractive optical elements from glass with continuous surface profiles

Diffractive optical elements (DOE) play an important role for laser beam shaping in industry, for example in lithography or parallel laser material processing. Typically such applications require high damage threshold and low background illumination (high contrast and efficiency). Usual DOE with binary phase (step-like) profiles are made microlithographically and suffer from substantial scattering on profile derivative discontinuities. That gives also tendency to lower damage threshold as compared to intrinsic material values. The LIMO approach is based contrarily on a proprietary, non etching material processing and is suitable for manufacturing of high-precision free programmable continuous surface profiles in optical glasses and crystals. We report on linear symmetric diffractive beam splitter 1:11 with high homogeneity and efficiency > 95% and discuss also other DOE designs. The design data, simulations with measured surface profiles and experimental intensity distributions are in very good agreement. Furthermore we report on a new type of optical attenuator composed from two DOE gratings. Its dynamic transmission range is 0.3% to 98%. The required lateral DOE shift is only 5 - 10 μm in the present design, so that the device can be very fast and applicable for dynamic intensity stabilization.

Fabrication of three-dimensional photonic crystals by interference lithography with low light absorption

We report on the fabrication of polymer templates of photonic crystals by means of holographic (or interference) lithography. The grating is written in a SU-8 photoresist using a He-Cd laser of wavelength 442 nm. The use of the wavelength found within the photoresist low absorption band enables fabricating structures that are uniform in depth. Parameters of the photoresist exposure and development for obtaining a porous structure corresponding to an orthorhombic lattice are determined.

Optical near-field scanning by microparticles suspended in immersion fluid

A new method of obtaining images with a resolution exceeding the diffraction limit of an optical microscope is proposed and experimentally implemented. The method is based on monitoring the pattern of free motion of microparticles over the sample surface and an analysis of the intensity of light scattered by these particles. In experiment, a threefold increase in the ultimate resolution of a microscope has been achieved.

Complete photonic band gap in icosahedral quasicrystals with a body-centered six-dimensional lattice

For the first time, the band structure of three-dimensional cubic photonic approximants of quasicrystals is studied theoretically. The approximants of different orders are found to have large, near-isotropic band gaps in a wide range of permittivity values. The effect of atom coordination on the size and threshold of the photonic band gap is explored. The existence of a complete band gap in the cubic photonic quasicrystal with a body-centered six-dimensional lattice is demonstrated.

Fabrication of three-dimensional metallodielectric photonic crystals by interference lithography

We report on the fabrication of metallodielectric photonic crystals by means of interference (or holographic) lithography and subsequent coating by gold nanoparticles. The grating is realized in a SU-8 photoresist using a He-Cd laser of wavelength 442 nm. The use of the wavelength found within the photoresist low absorption band enables fabricating structures that are uniform in depth. Parameters of the photoresist exposure and development for obtaining a porous structure corresponding to an orthorhombic lattice are determined. Coating of photonic crystals by gold nanoparticles is realized by reduction of chloroauric acid by a number of reductants in a water solution. This research shows that the combination of interference lithography and chemical coating by metal is attractive for the fabrication of metallodielectric photonic crystals.

Phase-locked detection mechanism in photorefractive waveguides

Abstract The mechanism of recording a static grating in a planar photorefractive waveguide by a moving interference pattern and an external ac electric field is discussed. The direction of the external field is perpendicular to the waveguide layer. The recording efficiency is studied theoretically.