Snowtonics: the photonics of snow?

Fuzzy optics.. not fuzzy like a car

Fresh snow is bright, white and opaque. What does this actually mean, optically? Fresh snow is opaque If you’ve seen snow, you will know this to be true. But why? Snow is made of, erm, snowflakes, which are made of ice, which is transparent, not opaque. Snow is what we call a multiple scatterer, in other words, most of the light that falls onto it is scattered around (inside the snow) several times before it gets out. The consequence of this is that light falling on the snow gets mixed up, randomised, and any information within it is scrambled. So, Continue reading

Gas sensing paper appears online

Simple diagram of an Integrating sphere

Jane Hodgkinson’s latest study on the use of integrating spheres in wavelength modulation spectroscopy has appeared on Applied Physics B‘s “online first service” The detection and quantification of gas concentrations by measurement of their optical absorption has considerable great scientific and commercial importance. Extending the optical pathlength in gas sample cells is of interest to improve the signal to noise ratio (SNR) of this technique. Integrating spheres have great promise as multipass gas cells that require minimal optical alignment. However, the exponential distribution of optical pathlengths might be expected to influence the measurement. In the paper it was found that Continue reading