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Université de Neuchâtel

Observation of amplitude and phase in ridge and photonic crystal waveguides operating at 1.55 μm by use of heterodyne scanning near-field optical microscopy

Tortora, Pierpasquale ; Abashin, M. ; Märki, Iwan ; Nakagawa, Wataru ; Vaccaro, Luciana ; Salt, Martin Guy ; Herzig, Hans-Peter ; Levy, U. ; Fainman, Y.

In: Optics Letters, 2005, vol. 30, no. 21, p. 2885-2887

We apply heterodyne scanning near-field optical microscopy (SNOM) to observe with subwavelength resolution the amplitude and phase of optical fields propagating in several microfabricated waveguide devices operating around the 1.55 μm wavelength. Good agreement between the SNOM measurements and predicted optical mode propagation characteristics in standard ridge waveguides demonstrates the...

Université de Neuchâtel

Optically tunable microcavity in a planar photonic crystal silicon waveguide buried in oxide

Märki, Iwan ; Salt, Martin Guy ; Herzig, Hans-Peter ; Stanley, Ross ; Melhaoui, L. El. ; Lyan, P. ; Fedeli, J. M.

In: Optics Letters, 2006, vol. 31, no. 4, p. 513-515

We present all-optical tuning and switching of a microcavity inside a two-dimensional photonic crystal waveguide. The photonic crystal structure is fabricated in silicon-on-insulator using complementary metal-oxide semiconductor processing techniques based on deep ultraviolet lithography and is completely buried in a silicon dioxide cladding that provides protection from the environment. By...

Université de Neuchâtel

Design and characterization of a tunable polarization-independent resonant grating filter

Niederer, Guido ; Nakagawa, Wataru ; Herzig, Hans-Peter ; Thiele, Hans

In: Optics Express, 2005, vol. 13, no. 6, p. 2196-2200

We present the design, analysis and characterization of a polarization-independent tunable resonant grating filter. Polarization independence is achieved by setting the plane of incidence parallel to the grating grooves and optimizing the fill factor to obtain a strong reflection peak for all incident polarization states. Experimental measurements show that approximate angular insensitivity to...

Université de Neuchâtel

Tuning the resonance of a photonic crystal microcavity with an AFM probe

Märki, Iwan ; Salt, Martin Guy ; Herzig, Hans-Peter

In: Optics Express, 2006, vol. 14, no. 7, p. 2969-2978

We present theoretical and experimental results on switching and tuning of a two-dimensional photonic crystal resonant microcavity by means of a silicon AFM tip, probing the highly localized optical field in the vicinity of the cavity. On-off switching and modulation of the transmission signal in the kHz range is achieved by bringing an AFM tip onto the center of the microcavity, inducing a...

Université de Neuchâtel

Tunable, Oblique Incidence Resonant Grating Filter for Telecommunications

Niederer, Guido ; Herzig, Hans-Peter ; Shamir, Joseph ; Thiele, Hans ; Schnieper, Marc ; Zschokke, Christian

In: Applied Optics, 2004, vol. 43, no. 8, p. 1683-1694

We have designed a tunable, oblique-incidence resonant grating filter that covers the C band as an add-drop device for incident TE-polarized light. We tune the filter by tilting a microelectromechanical systems platform onto which the filter is attached. The fabrication tolerances as well as the role of finite incident-beam size and limited device size were addressed. The maximum achievable...

Université de Neuchâtel

Efficient Beam Shaping of Linear, High-Power Diode Lasers by Use of Micro-Optics

Schilling, Andreas ; Herzig, Hans-Peter ; Stauffer, Laurent ; Vokinger, Urs ; Rossi, Markus

In: Applied Optics, 2001, vol. 40, no. 32, p. 5852-5859

We have designed, fabricated, and characterized a micro-optical beam-shaping device that is intended to optimize the coupling of an incoherent, linearly extended high-power diode laser into a multimode fiber. The device uses two aligned diffractive optical elements (DOEs) in combination with conventional optics. With a first prototype, we achieved an overall efficiency of 28%. Straightforward...

Université de Neuchâtel

Phase function encoding of diffractive structures

Schilling, Andreas ; Herzig, Hans-Peter

In: Applied Optics, 2000, vol. 39, no. 29, p. 5273-5279

We analyzed the direct sampling (DS) method for diffractive lens encoding, using exact electromagnetic diffraction theory. In addition to previously published research [Pure Appl. Opt. 7, 565 (1998)] we present what we believe to be new results for TM polarization. We found that the validity of the scalar-based DS method is even more extended for TM than for TE polarization. Additionally, we...

Université de Neuchâtel

Application of the boundary-element method to the interaction of light with single and coupled metallic nanoparticles

Rockstuhl, Carsten ; Salt, Martin Guy ; Herzig, Hans-Peter

In: Journal of the Optical Society of America A, 2003, vol. 20, no. 10, p. 1969-1973

The boundary-element method is applied to the interaction of light with resonant metallic nanoparticles. At a certain wavelength, excitation of a surface plasmon takes place, which leads to a resonantly enhanced near-field amplitude and a large scattering cross section. The resonance wavelength for different scatterer geometries is determined. Alteration of the scattering properties in the...

Université de Neuchâtel

Calculation of the torque on dielectric elliptical cylinders

Rockstuhl, Carsten ; Herzig, Hans-Peter

In: Journal of the Optical Society of America A, 2005, vol. 22, no. 1, p. 109-116

We present our investigation of the torque exerted on dielectric elliptical cylinders by highly focused laser beams. The calculations are performed with rigorous diffraction theory, and the size-dependent torque is analyzed as a function of the axis ratio. It is found that highly elongated particles will experience a reversal of the torque for a radius that is approximately one third of the...

Université de Neuchâtel

Analysis of the phonon-polariton response of silicon carbide microparticles and nanoparticles by use of the boundary element method

Rockstuhl, Carsten ; Salt, Martin Guy ; Herzig, Hans-Peter

In: Journal of the Optical Society of America B, 2005, vol. 22, no. 2, p. 481-487

We investigate the small-particle phonon-polariton response of several microstructures that are made of silicon carbide (SiC). Phonon polaritons can be excited in a wavelength region between 10 and 12 µm. Simple structures such as elliptical cylinders support phonon polaritons at two wavelengths, which depend on the axis ratio of the particle. In particles with a more irregular shape such as...