F.C. Blom

Visualizing the whispering gallery modes in a cylindrical optical microcavity.

Whispering gallery modes in cylindrical integrated optics microcavities have, for what is to our knowledge the first time, been mapped with a photon scanning tunneling microscope. Optical images were obtained with a spatial resolution of 50 nm. By combination of information on the spatial optical distributions with wavelength-dependent measurements, an unexpectedly rich variety of intracavity phenomena, such as polarization conversion and interference of copropagating and counterpropagating modes, could be directly observed. A quantitative comparison of the experimental data with computer simulations results in a comprehensive understanding of the various whispering gallery modes inside the microcavity.

Detailed analysis of the intracavity phenomena inside a cylindrical microresonator

Based on a rigorous analysis of the intensity distribution inside a cylindrical microresonator (MR), a detailed description of the wavelength and spatial dependence of the intracavity intensity is given. The theory is in accordance with photon scanning tunneling microscopy (PSTM) of an integrated optics MR. Good agreement between the theory and the PSTM measurements is found.

Experimental analysis of the whispering-gallery modes in a cylindrical optical microcavity

A real-space study of a cylindrical integrated optical microcavity by means of a photon scanning-tunneling microscope with a resolution of 50 nm reveals optical intensity distributions in great detail. Moreover, novel phenomena such as polarization conversion and conversion from copropagation to counterpropagation are observed. We present detailed maps of the optical field distribution of the whispering-gallery modes inside the microcavity as a function of both wavelength and position. We have made a quantitative comparison between measured and calculated field distributions. As a result, the buildup of the various whispering-gallery modes is better understood.

High-resolution photon-scanning tunneling microscope measurements of the whispering gallery modes in a cylindrical microresonator

A detailed analysis of spatio-spectral photon scanning tunneling microscope scans of the light intensity inside a cylindrical microresonator has been carried out. By comparing the experimental results with theory, it is shown that the inclusion of spectral mode-beat phenomena is crucial for an accurate analysis of the modes present in the microresonator.

Evaluation of polymer based third order nonlinear integrated optics devices

Nonlinear polymers are promising materials for high speed active integrated optics devices. In this paper we evaluate the perspectives polymer based nonlinear optical devices can offer. Special attention is directed to the materials aspects. In our experimental work we applied mainly Akzo Nobel DANS side-chain polymer that exhibits large second and third order coefficients. This material has been characterized by third harmonic generation, z-scan and pump-probe measurements. In addition, various waveguiding structures have been used to measure the nonlinear absorption (two photon absorption) on a ps time-scale. Finally an integrated optics Mach-Zehnder interferometer has been realized and evaluated. It is shown that the DANS side-chain polymer has many of the desired properties: the material is easily processable in high-quality optical waveguiding structures, has low linear absorption and its nonlinearity has a pure electronic origin. More materials research has to be done to arrive at materials with higher nonlinear coefficients to allow switching at moderate light intensity (< 1 W peak power) and also with lower nonlinear absorption coefficients.