Much of my research presented here has been in developing novel levitated systems for the studies in macroscopic quantum mechanics, nano-thermodynamics and metrology.
Levitated Electromechanics
Ion trapping technology is over 50 years old. Whereby oscillating electric fields are used to generate a potential well, in which charged particles can be trapped. This technology is being used for quantum computers to trap atomic ions and in mass spectrometers, to name a few. We are interested in using this technology to levitate charged microspheres for studies in nano-thermodynamics and as a stochastic simulator.
Levitated Optomechanics
State Control and State Preparation
When light is focussed using lenses or mirrors, it generates an intense focal spot. In this spot, dielectric particles can be trapped. Just like the tractor beam in star trek! Except here, instead of starships, we are trapping microscopic particles with diameters of 40 nm – 300 nm. This technique of optically trapping objects is known as Optical Tweezers.
Optical tweezers has shown great advancement in recent decades specifically in the study of biological sciences. Such optical tweezers, trap particles in solution. The field of levitated optomechanics is interested in regime of when a single photons couple to the mechanical motion (i.e. x, y, z motion) levitated particle. For this the trapping is done in vacuum In the aimof generating and studying macroscopic quantum systems.
Specifically, we utalised the paraboloidal mirrors to trap silica nanoparticles. We were able to utalise cool nanoaprticles down to a few mK center of mass temperatures as well as carry out squeezing and Wigner reconstruction.
Ultra-Weak Force Sensing
What happens when you levitate an object, the shape of which you do not know? It turns out the very physics that enables rotation of rigid bodies in levitated optomechanics is also senstive to the shape or specifically the anistropy of the object.
Giving rise to rich spectrum. We showed that by meticulously analysing the motional spectrum of the trapped nanoparticle you can determine its anistropy. Using this we were also able to identify novel rotional dyanmics such as precession and nutation motions that a rotating object undergoes due to optical torques.
Muddassar A Rashid 