Dissertation/ Thesis

Longitudinal optical binding

التفاصيل البيبلوغرافية
العنوان: Longitudinal optical binding
المؤلفون: Metzger, Nikolaus K.
المساهمون: Dholakia, Kishan
بيانات النشر: University of St Andrews, 2008.
سنة النشر: 2008
المجموعة: University of St Andrews
مصطلحات موضوعية: 535, Optical, Tweezers, Array, Binding, Nonlinear, System
الوصف: Longitudinal optical binding refers to the light induced self organisation of micro particles in one dimension. In this thesis I will present experimental and theoretical studies of the separation between two dielectric spheres in a counter-propagating (CP) geometry. I will explore the bistable nature of the bound sphere separation and its dependency on the refractive index mismatch between the spheres and the host medium, with an emphasis on the fibre separation. The physical under pining principle of longitudinal optical binding in the Mie regime is the refocusing effect of the light field from one sphere to its nearest neighbour. In a second set of experiments I developed means to visualise the field intensity distribution responsible for optical binding using two-photon fluorescence imaging from fluorescein added to the host medium. The experimental intensity distributions are compared to theoretical predictions and provide an in situ method to observe the binding process in real time. This coupling via the refocused light fields between the spheres is in detailed investigated experimentally and theoretically, in particular I present data and analysis on the correlated behaviour of the micro spheres in the presence of noise. The measurement of the decay times of the correlation functions of the modes of the optically bound array provides a methodology for determining the optical restoring forces acting in optical binding. Interestingly micro devices can be initiated by means of the light-matter interaction. Light induced forces and torques are exerted on such micro-objects that are then driven by the optical gradient or scattering force. I have experimentally investigate how the driving light interacts with and diffracts from the motor, utilising two-photon imaging. The micromotor rotation rate dependence on the light field parameters is explored and theoretically modelled. The results presented will show that the model can be used to optimise the system geometry and the micromotor.
نوع الوثيقة: Electronic Thesis or Dissertation
اللغة: English
URL الوصول: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.552134
رقم الانضمام: edsble.552134
قاعدة البيانات: British Library EThOS