Simultaneously shaping the intensity and phase of light for optical nanomanipulation

TL;DR

This paper presents a fast hologram generation method that enables simultaneous control of light's intensity and phase, enhancing optical manipulation capabilities beyond traditional techniques.

Contribution

A novel inverse Fourier transform-based method for rapid hologram computation that controls both intensity and phase distributions simultaneously.

Findings

Successfully generated complex optical patterns with controlled intensity and phase.

Demonstrated optical trapping and transportation of nanoparticles using the new holography method.

Validated the approach through experimental measurements of hologram projections.

Abstract

Holographic optical tweezers can be applied to manipulate microscopic particles in arbitrary optical patterns, which classical optical tweezers cannot do. This ability relies on accurate computer-generated holography (CGH), yet most CGH techniques can only shape the intensity profiles while the phase distributions are random. Here, we introduce a new method for fast generation of holograms that allows for simultaneously shaping both the intensity and phase distributions of light. The method uses a discrete inverse Fourier transform formula to directly calculate a hologram in one step, in which a random phase factor is introduced into the formula to enable simultaneous control of intensity and phase. Various optical patterns can be created, as demonstrated by the experimentally measured intensity and phase profiles projected from the holograms. The simultaneous shaping of intensity and phase of light provides new opportunities for optical trapping and manipulation, such as optical transportation of metal nanoparticles in ring traps with linear and nonlinear phase distributions.