An optical tweezers apparatus uses a tightly focused laser to generate a trapping force that can capture and move small particles under a microscope. Because it can precisely and nondestructively manipulate objects such as individual cells and their internal components, the optical tweezers is extremely useful in biological physics research. In this experiment you will use optical tweezers to t...

H€ansch TW, Picqué N. Frequency combs. In: Tr€ager F, editor. Handbook of lasers and optics. 2nd ed. Springer Berlin: Heidelberg; (2012). Ideguchi T et al. Adaptive real-time dual comb spectroscopy. arXiv:1201.4177 (2012). Jacquet, P., et al. Frequency comb Fourier transform spectroscopy with kHz optical resolution. In: Fourier transform spectroscopy. Washington, DC: Optical Society of America;...

b) Atoms have some probability of absorbing photons from the laser beam, thereby being kicked along the direction of the beam. This processes can be modelled classically by supposing that the polarizability of the atom has an imaginary part: α = α′ + iα′′. Deduce the (time-averaged) force on an atom along the direction of propagation of a linearly polarized plane electromagnetic wave in terms o...

A compact optoelectronic tweezers system for combined cell manipulation and analysis is presented. CMOS-controlled gallium nitride micro-LED arrays are used to provide simultaneous spatio-temporal control of dielectrophoresis traps within an optoelectronic tweezers device and fluorescence imaging of contrasting dye labelled cells. This capability provides direct identification, selection and co...

Abstract Sensing sensitivity is the key performance of optical tweezers. By adjusting frequency and magnitude an applied Coulomb force as input tweezers, we directly measured signal-to-noise ratio (SNR) a system indirectly calculated actual noise magnitude. Combined with output filter, relationship between SNR bandwidths was studied. We established simulation model using Simulink simulated forc...

Holographic Optical Tweezers (HOT) are a versatile way of manipulating microscopic particles in 3D. However, their ease of use has been hampered by the computational load of calculating the holograms, resulting in an unresponsive system.Wepresent a program for generating these holograms on a consumer Graphics Processing Unit (GPU), coupled to an easy-to-use interface in LabVIEW (National Instru...

Binding interactions between oligo­molecules and surfaces have become important in many research fields. Specifically, these interactions can be extended to semiconductor self­assembly (1) for materials that are difficult to produce industrially. A gradient force optical trap (op­ tical tweezers) offers an intriguing method to investigate these interactions at a molecular level by allowing the ...

Molecular motors are nonequilibrium open systems that convert chemical energy to mechanical work. Here we investigate the nonequilibrium energetics of a single molecule kinesin by measuring the motion of an attached probe particle and its response to external forces with optical tweezers. The sum of the heat dissipation estimated from the violation of the fluctuation-response relation and the o...

During the past decade, local force measurement techniques, such as atomic force microscopy and optical tweezers, were used to study the elastic properties and mechanically induced structural transitions of nucleic acids at the single-molecule level. Single-molecule manipulation has also increasingly been used to investigate DNA-dependent enzymatic processes, with implications for unfolding and...

Many compounds have been tested as inhibitors or modulators of amyloid β-protein (Aβ) assembly in hope that they would lead to effective, disease-modifying therapy for Alzheimer's disease (AD). These compounds typically were either designed to break apart β-sheets or selected empirically. Two such compounds, the natural inositol derivative scyllo-inositol and the green-tea-derived flavonoid epi...