Optical tweezers use the forces exerted by a strongly focused beam of light to trap and move objects ranging in size from tens of nanometres to tens of micrometres. Since their introduction in 1986, the optical tweezer has become an important tool for research in the fields of biology, physical chemistry and soft condensed matter physics. Recent advances promise to take optical tweezers out of the laboratory and into the mainstream of manufacturing and diagnostics; they may even become consumer products. The next generation of single-beam optical traps offers revolutionary new opportunities for fundamental and applied research.

http://physics.nyu.edu/grierlab/nreview2c/nreview2c.pdf

A revolution in optical manipulation

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

/pdf/the-observation-of-gravitational-waves-from-a-binary-black-58srpupgg9.pdf

The Observation of Gravitational Waves from a Binary Black Hole Merger

With few exceptions biological tissues strongly scatter light, making high-resolution deep imaging impossible for traditional⎯including confocal⎯fluorescence microscopy. Nonlinear optical microscopy, in particular two photon–excited fluorescence microscopy, has overcome this limitation, providing large depth penetration mainly because even multiply scattered signal photons can be assigned to their origin as the result of localized nonlinear signal generation. Two-photon microscopy thus allows cellular imaging several hundred microns deep in various organs of living animals. Here we review fundamental concepts of nonlinear microscopy and discuss conditions relevant for achieving large imaging depths in intact tissue.

/pdf/deep-tissue-two-photon-microscopy-2aqu6d6n65.pdf

Deep tissue two-photon microscopy

Multiphoton microscopy (MPM) has found a niche in the world of biological imaging as the best noninvasive means of fluorescence microscopy in tissue explants and living animals. Coupled with transgenic mouse models of disease and 'smart' genetically encoded fluorescent indicators, its use is now increasing exponentially. Properly applied, it is capable of measuring calcium transients 500 microm deep in a mouse brain, or quantifying blood flow by imaging shadows of blood cells as they race through capillaries. With the multitude of possibilities afforded by variations of nonlinear optics and localized photochemistry, it is possible to image collagen fibrils directly within tissue through nonlinear scattering, or release caged compounds in sub-femtoliter volumes.

/pdf/nonlinear-magic-multiphoton-microscopy-in-the-biosciences-3fszv5aq8z.pdf

Nonlinear magic: multiphoton microscopy in the biosciences

Diarylethenes for Memories and Switches

A scanning near-field optical microscope (SNOM) is employed to directly visualize the focusing and focal depth modulation effect of a step corrugated nanoplasmonic slit fabricated with focused ion beam milling.

Direct visualization of focusing effect of step corrugated nanoplasmonic slits

In this paper, we report on our recent progress on the development of super-resolution optical disk for ultra-high density optical data storage. A novel optical two-beam technique compatible with a standard optical drive is applied in the recording and reading process to enable the 10 Terabytes optical disk development.

Super-resolution optical disks beyond 10 Terabytes

We have developed a system combining an optical tweezers and a confocal microscope for the study of cell mechanics. The system enables us to measure how mechanical forces are distributed within cells. This provides an important insight into the mechanisms by which how cells sense and respond to mechanical forces.

https://researchbank.swinburne.edu.au/file/e36b0a03-4730-4045-a58c-a2908ca92461/1/PDF (Published version).pdf

Combining optical tweezing and confocal microscopy for the study of cell mechanics

Image modeling based on the Monte Carlo method is time consuming because a large number of incident photons are required to ensure a required accuracy. The requiring of computational time increases significantly when images of complicated objects embedded in a turbid medium are modeled. To address this problem, the concept of the effective point spread function (EPSF) has been introduced in this chapter for imaging through turbid media [1]. Section 4.1 provides the detailed conceptual development of the EPSF and numerical simulations of image formation of one-dimensional and two-dimensional objects are detailed in Sect. 4.2.

Effective Point Spread Function

In this paper, we discuss the spectral encoding capability of gold nanorods and its application to high-density optical data storage.

Min Gu

Papers

Direct visualization of focusing effect of step corrugated nanoplasmonic slits

Super-resolution optical disks beyond 10 Terabytes

Combining optical tweezing and confocal microscopy for the study of cell mechanics

Effective Point Spread Function

Spectral encoding using nanorods for high - density optical data storage