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Silica Aerogel

The Nonlinear Optical Memory Effect

Light propagating in random media produces characteristic speckle patterns, which remain correlated for small perturbations of the parameters of the incoming beam, including e.g. its angle and position. This behaviour is known as memory effect. In a paper published in Optics Letters, fruit of the collaboration of our group with Dr Tom Vettenburg (University of Dundee) and Prof. Claudio Conti (CNR, Italy), we generalise the memory effect to the case of light propagating in random nonlinear media. In particular, in a series of pump-probe experiments, we quantify the nonlinear memory effect produced by the opto-thermal response of silica aerogel. In this work, the memory effect… Read More »The Nonlinear Optical Memory Effect

Perturbation of Transmission Matrices in Nonlinear Random Media

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In this paper, published in Annalen der Physik, we present the direct measurement of the nonlinear transmission matrix of complex materials, exploiting the strong optothermal nonlinearity of scattering silica aerogel. It is shown that the dephasing effects due to nonlinearity are both controllable and reversible, opening the road to applications based on the nonlinear response of random media  

Research Visit to the University Sapienza, Rome

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Congratulations to Adam Fleming, who won a Short Term Visit grant from SUPA in order research Random Lasing in Silica Aerogels with Prof. Claudio Conti at the University Di Spienza, Rome! Avoiding the cold autumnal months, he will be gone for one month in October!      

Optothermal Nonlinearity of Silica Aerogel

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In a paper published in Appl. Phys. Lett., we report the first measurements of optothermal nonlinearity of silica aerogels. Silica based aerogels are ultra porous materials with refractive index close to unity. Their extreme porosity is responsible for very low thermal conductivity, which in turn leads to very peculiar optothermal properties. In this paper, in collaboration with researchers at the University Sapienza and CNR, we measured the optothermal nonlinear coefficient of silica based aerogels in the visible range. The full article can be found here.

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