Optical levitation using broadband light

Abstract

The ability to create dynamic, tailored optical potentials has become important across fields ranging from biology to quantum science. We demonstrate a method for the creation of arbitrary optical tweezer potentials using the broadband spectral profile of a superluminescent diode combined with the chromatic aberration of a lens. A tunable filter, typically used for ultrafast laser pulse shaping, allows us to manipulate the broad spectral profile and therefore the optical tweezer potentials formed by focusing of this light. We characterize these potentials by measuring the Brownian motion of levitated nanoparticles in vacuum and also demonstrate interferometric detection and feedback cooling of the particle's motion. This simple and cost-effective technique will enable wide application and allow rapid modulation of the optical potential landscape in excess of megahertz frequencies. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Realizing Einstein’s Mirror: Optomechanical Damping with a Thermal Photon Gas

“…Amplifiers do not, however, have a flat spectral profile. This can be ameliorated by using a spectral filter on the input to compensate for this variation [11,21,22]. When illuminated with this amplified light, the force on the mirror in the moving frame is…”

“…Furthermore, we assume that the amplified light is tightly focused using a lens to a spot size of area A w . The particle could be levitated in a Paul trap [9], or by the thermal light itself [11]. In the laboratory frame, the wave vector of an incident photon is given by k in ¼ ½k x k y k z , where k in ¼ ω in =c.…”

“…We have shown that small, well isolated optomechanical systems can be damped and thermalized by a thermal photon gas as originally envisioned by Einstein. Such an experiment is feasible using thermal light sources [4,5] and recent advances in optomechanics [11,13,14]. An experimental demonstration using a levitated optomechanical object, such as a charged nanoparticle in a Paul trap [9] or a neutral nanoparticle in an optical trap [12,13,29,30], in ultrahigh vacuum seems ideal.…”

“…Although we have calculated the damping from a 2D source, a 1D source [5] could potentially be focused more tightly, leading to a higher damping. Amplified LEDs and superluminescent diodes, which produce thermal light [8,31] and have been used to trap dielectric spheres [11], could also be considered for investigating thermal radiation damping. Our results raise the possibility that by increasing or decreasing the bulk temperature of a thermalized light source one The damping time 2π=Γ x;y;z of a 200 nm radius silica sphere along the x, y, and z axes when the particle is illuminated with a thermal photon gas focused to a spot size of w ¼ 1 μm.…”

“…This opens up the possibility of producing more intense thermal sources when compared to a BB. We show that these sources will allow the experimental realization of the optical damping of microscopic optomechanical objects [9,[11][12][13][14] as envisioned by Einstein.…”