Michael T. Cone

Bright emission from a random Raman laser

Random lasers are a developing class of light sources that utilize a highly disordered gain medium as opposed to a conventional optical cavity. Although traditional random lasers often have a relatively broad emission spectrum, a random laser that utilizes vibration transitions via Raman scattering allows for an extremely narrow bandwidth, on the order of 10 cm−1. Here we demonstrate the first experimental evidence of lasing via a Raman interaction in a bulk three-dimensional random medium, with conversion efficiencies on the order of a few percent. Furthermore, Monte Carlo simulations are used to study the complex spatial and temporal dynamics of nonlinear processes in turbid media. In addition to providing a large signal, characteristic of the Raman medium, the random Raman laser offers us an entirely new tool for studying the dynamics of gain in a turbid medium.

Ultrasensitive detection of waste products in water using fluorescence emission cavity-enhanced spectroscopy

Significance Clean water is paramount to human health. Contaminants, such as human waste products in drinking water, can result in significant health issues. In this article, we present a technique for detection of trace amounts of human or animal waste products in water. This technique could allow for real-time assessment of water quality without the need for expensive laboratory equipment. Clean water is paramount to human health. In this article, we present a technique for detection of trace amounts of human or animal waste products in water using fluorescence emission cavity-enhanced spectroscopy. The detection of femtomolar concentrations of urobilin, a metabolic byproduct of heme metabolism that is excreted in both human and animal waste in water, was achieved through the use of an integrating cavity. This technique could allow for real-time assessment of water quality without the need for expensive laboratory equipment.

Robust commercial diffuse reflector for UV-VIS-NIR applications.

We report the development and testing of a new commercially available diffuse reflecting material with reflectivities in the visible comparable to industry-leading products. This new diffuse reflector consists of solid quartz in which there is a dense distribution of tiny pockets of air. The multiple reflections by the quartz-air interfaces of these air pockets transforms a highly transmissive base material into a highly diffuse reflecting material.

Measuring the Absorption Coefficient of Strongly Scattering Samples Using Integrating Cavity Ring-Down Spectroscopy

We report a novel technique for the precise and accurate measurement of the optical absorption coefficient of strongly scattering samples via ring-down spectroscopy inside ultra-high reflectivity integrating cavities. Experimental results are discussed.

Measuring the absorption coefficient of biological materials using integrating cavity ring-down spectroscopy

We report a simple method for accurate and precise measurement of the optical absorption coefficient of cellular structures, even in the presence of strong scattering. Experimental results are discussed using retinal pigment epithelium cells.

Ring-Down Absorption Spectroscopy in an Integrating Cavity

A new diffuse reflector has been developed whose reflectivity in the 250 nm to 1 micron spectral region is so high that ring-down spectroscopy of scattering aerosols in an integrating cavity is now possible.