Effect of long- and short-term exposure to laser light at 1070 nm on growth of Saccharomyces cerevisiae.

The effect of a 1070-nm continuous and pulsed wave ytterbium fiber laser on the growth of Saccharomyces cerevisiae single cells is investigated over a time span of 4 to 5 h. The cells are subjected to optical traps consisting of two counterpropagating plane wave beams with a uniform flux along the x, y axis. Even at the lowest continuous power investigated-i.

Three-dimensional imaging in three-dimensional optical multi-beam micromanipulation.

In this work, we present a method providing real-time, low cost, three-dimensional imaging in a three-dimensional optical micromanipulation system. The three-dimensional imaging system is based on a small form factor LED based projector. The projector is used to dynamically shape the rear illumination light in a counter-propagating beam-trapping setup.

2D optical manipulation and assembly of shape-complementary planar microstructures.

Optical trapping and manipulation offer great flexibility as a non-contact microassembly tool. Its application to the assembly of microscale building blocks may open new doors for micromachine technology. In this work, we demonstrate all-optical assembly of microscopic puzzle pieces in a fluidic environment using programmable arrays of trapping beams.

Fully automated beam-alignment and single stroke guided manual alignment of counter-propagating multi-beam based optical micromanipulation systems.

In a previous paper [J. S. Dam et al, Opt.

Computerized "drag-and-drop" alignment of GPC-based optical micromanipulation system.

In the past, aligning the counterpropagating beams in our 3D real-time generalized phase contrast (GPC) trapping system has been a task requiring moderate skills and prior experience with optical instrumentation. A ray transfer matrix analysis and computer-controlled actuation of mirrors, objective, and sample stage has made this process user friendly. The alignment procedure can now be done in a very short time with just a few drag-and-drop tasks in the user-interface.

GPC-based optical micromanipulation in 3D real-time using a single spatial light modulator.

Using a novel dual-beam readout with the generalized phase contrast (GPC) method, a multiple-beam 3D real-time micromanipulation system requiring only one spatial light modulator (SLM) has been realized. A theoretical framework for the new GPC scheme with two parallel illumination beams is presented and corroborated with an experimental demonstration. Three-dimensional arrays of polystyrene microbeads were assembled in the newly described system.

Autonomous and 3D real-time multi-beam manipulation in a microfluidic environment.

The Generalized Phase Contrast (GPC) method of optical 3D manipulation has previously been used for controlled spatial manipulation of live biological specimen in real-time. These biological experiments were carried out over a time-span of several hours while an operator intermittently optimized the optical system. Here we present GPC-based optical micromanipulation in a microfluidic system where trapping experiments are computer-automated and thereby capable of running with only limited supervision.

Three-dimensional forces in GPC-based counterpropagating-beam traps.

We theoretically investigate the three-dimensional (3D) trapping force acting on a microsphere held in a pair of counterpropagating beams produced by the generalized phase contrast (GPC) method. In the case of opposing beams of equal power, we identify the range of beam waist separation s that results in a stable 3D optical potential-well by assessing the dependence of the axial and transverse force curves on s. We also examine how the force curves are influenced by other parameters such as size and refractive index of the microsphere.

High-speed phase modulation using the RPC method with a digital micromirror-array device.

An improved implementation of the reverse phase contrast (RPC) method for rapid optical transformation of amplitude patterns into spatially similar phase patterns using a high-speed digital micromirror-array device (DMD) is presented. Aside from its fast response, the DMD also provides an electronically adjustable and inherently aligned input iris that simplifies the optimization of the RPC system. In the RPC optimization, we illustrate good agreement between experimentally obtained and theoretically predicted optimal iris size.