Eric Ampem-Lassen

Refractive-index profiling of optical fibers with axial symmetry by use of quantitative phase microscopy

The application of quantitative phase microscopy to refractive-index profiling of optical fibers is demonstrated. Phase images of axially symmetric optical fibers immersed in index-matching fluid are obtained, and the inverse Abel transform is used to obtain the radial refractive-index profile. This technique is straightforward, nondestructive, repeatable, and accurate. Excellent agreement, to within approximately 0.0005, between this method and the index profile obtained with a commercial profiler is obtained.

Nano-manipulation of diamond-based single photon sources

The ability to manipulate nano-particles at the nano-scale is critical for the development of active quantum systems. This paper presents a technique to manipulate diamond nano-crystals at the nano-scale using a scanning electron microscope, nano-manipulator and custom tapered optical fibre probes. The manipulation of a approximately 300 nm diamond crystal, containing a single nitrogen-vacancy centre, onto the endface of an optical fibre is demonstrated. The emission properties of the single photon source post manipulation are in excellent agreement with those observed on the original substrate.

Refractive index profiling of axially symmetric optical fibers: a new technique

We present a new technique for determining the refractive index profiles of axially symmetric optical fibers based on imaging phase gradients introduced into a transmitted optical field by a fiber sample. An image of the phase gradients within the field is obtained using a new non-interferometric technique based on bright field microscopy. This provides sufficient information to reconstruct the refractive index profile using the inverse Abel transform. The technique is robust, rapid and possesses high spatial resolution and we demonstrate its application to the reconstruction of the refractive index profiles of a single-mode and a multimode optical fiber.

A highly efficient two level diamond based single photon source

An unexplored diamond defect center that is found to emit stable single photons at a measured rate of 1.6 MHz at room temperature is reported. The center, identified in chemical vapor deposition grown diamond crystals, exhibits a sharp zero phonon line at 734 nm with a full width at half maximum of ∼4 nm. The photon statistics confirm that the center is a single emitter and provides direct evidence of a true two level single quantum system in diamond.

Refractive index profiling of optical fibers using differential interference contrast microscopy

Here we demonstrate the use of differential interference contrast microscopy with the inverse Abel transform to accurately obtain the refractive-index profile of a single-mode optical fiber. The application of this nondestructive imaging analysis technique provides high precision refractive-index information about the fiber. This technique is robust, rapid, and has diffraction limited spatial resolution.

Index mapping for fibers with symmetric and asymmetric refractive index profiles

The application of phase imaging to refractive index profiling of an optical fiber slice is described. It is shown that the refractive index profile of axially symmetric and asymmetric optical fibers can be obtained from quantitative phase image of thin transverse optical fiber slices. Although this method requires careful and time consuming sample preparation, one advantage of this technique is that it can be applied to a wide range of optical fibers. In this paper results for both symmetric and non-symmetric fibers are presented and good agreement with the industry-standard refracted near-field technique demonstrated.

Processing of Diamond: Towards All-Diamond Integrated Optics

Diamond photonic devices present a range of opportunities due to their unique properties. This paper presents progress in the fabrication of diamond waveguides using reactive ion etching (RIE), as a step towards all-diamond optics.

Diamond single photon sources

We are currently developing a diamond single photon source based on patented technology held at the University of Melbourne. The key technology is the growth of diamond nanocrystals containing single photon sources directly on optical fibre endfaces