SHG light from graphene shows whether it's single- or multilayer

Light can serve as a probe of material structure, sometimes as a result of nonlinear effects. Scientists at the University of Toronto (Toronto, ON, Canada) are using optical second-harmonic generation (SHG) by graphene to determine whether the graphene is single- or multilayered. The technique is useful to physicists, material scientists, and nanotechnologists, and also can potentially study other effects on graphene such as effects of external electric fields and of adsorbates.

A titanium:sapphire laser provided 1.0 nJ, 150 fs pump pulses at an 800 nm wavelength; the pulses were attenuated to 0.06 nJ so as not to damage the graphene. Layers of graphene were mounted on a 300 nm film of silicon dioxide on a silicon substrate, which was in turn mounted on rotation and translation stages. The p-polarized light was focused on the graphene at a 60° angle, producing a 7 × 10 µm spot. P-polarized 400 nm SHG light was optically filtered and detected by a photon-counting photomultiplier tube. When the signal as a function of azimuth angle showed a four-lobed pattern characteristic of the substrate, the researchers knew the graphene was single layer; if the pattern was three-lobed (characteristic of graphene), then more than one layer was present. Contact Jesse Dean at jdean@physics.utoronto.ca.

More Laser Focus World Current Issue Articles
More Laser Focus World Archives Issue Articles

Most Popular Articles

Webcasts

Opportunities in the Mid-IR

The technology for exploiting the mid-IR is developing rapidly:  it includes quantum-cascade lasers and other sources, spectroscopic instruments of many...

Fiber Optic Sensors – Fundamentals, Principles and Applications

In this webcast, sponsored by Nufern, we focus on optical fiber sensing technology.  Fundamental concepts will be presented first, followed by the under...

Infinite Possibilities – Easily Combining Scanner and Servo Motion

High precision motion control applications such as laser micromachining, 2-photon polymerization, glass panel and film patterning, and additive manufacturing...

Solutions in Search of Problems: What Spectroscopy Can Do for You

Spectroscopy is so pervasive that most of us take it for granted. We use it for routine laboratory and test measurements without appreciating how those same ...

Technical Digests

HIGH-ENERGY LASER COATINGS: Eliminating laser damage proactively

High-power and high-energy thin-film antireflection coatings for laser optics require careful des...
Sponsored by

LIBS -- spectroscopy for remote identification of materials

Laser-induced-breakdown spectroscopy (LIBS) uses a pulsed laser to vaporize a small sample of a s...
Sponsored by

Laser Tools for Materials Processing

Laser materials processing requires not only the appropriate industrial laser system, but also a ...
Sponsored by

Click here to have your products listed in the Laser Focus World Buyers Guide.

RELATED PRODUCTS

Phantom ir300

The Phantom ir300 provides extended spectral response beyond visible light spectrum up ...

Miro Airborne

Miro Airborne is a high-speed camera designed for airborne applications.

Phantom Miro Family

The Phantom Miro family are small, lightweight digital high-speed cameras.

RELATED COMPANIES

Photonics Bretagne

Offers a cluster composed of research centers, schools and companies all in the field o...

Raw Communications

Provider of marketing services in the fiber optic data communications industry includin...

XiO Photonics B V

Offers strong competence in integrated optical products for visible light applications....

Social Activity

  •  
  •  
  •  
  •  
  •  
Copyright © 2007-2014. PennWell Corporation, Tulsa, OK. All Rights Reserved.PRIVACY POLICY | TERMS AND CONDITIONS