Rules for writing abstracts
Original [Deliberately separate sentences.]
The design of the helium-neon laser is not complex by modern standards.
They consist of only three essential components and operate by the processes of stimulated emission and light amplification.
Because of their many advantages over other types of laser, helium-neon lasers are used for many applications in research and industry.
Revised [Emphasis used to illustrate word choice.]
The simplicity of the helium-neon laser illustrates basic laser principles.
[or three basic laser components]
Atoms excited by a discharge tube spontaneously emit an electromagnetic wave which in turn stimulates atoms to emit light in phase (in step) with the stimulating wave.
This new emission amplifies the passing wave, and mirrors can enhance the process to produce an intense, coherent beam of light.
[Nature Nanotechnolgy 2, 114-120 (2007) Ref: Mo Li, H X Tang, M L Roukes, Ultra-sensitive NEMS-based cantilevers for sensing, scanned probe and very high-frequency applications.]
Scanning probe microscopies (SPM) and cantilever-based sensors generally
use low-frequency mechanical devices of microscale dimensions or larger.
Almost universally, off-chip methods are used to sense displacement in these devices, but this approach is not suitable for nanoscale devices.
Nanoscale mechanical sensors offer a greatly enhanced performance that is unattainable with microscale devices.
Here we describe the fabrication and operation of self-sensing nanocantilevers with fundamental mechanical resonances up to very high frequencies (VHF).
[Specifically, self-sensing nanocantilevers can achieve very high frequencies.]
These devices use integrated electronic displacement transducers based on piezoresistive thin metal films, permitting straightforward and optimal nanodevice readout.
[Further, integrated electronic displacement transducers on piezoresistive thin metal films permit straightforward and optimal nanodevice readout.]
This non-optical transduction enables applications requiring previously inaccessible sensitivity and bandwidth, such as fast SPM and VHF force sensing.
Detection of 127 MHz cantilever vibrations is demonstrated with a thermomechanical-noise-limited displacement sensitivity of 39 fm Hz-1/2.
Our smallest devices, with dimensions approaching the mean free path at atmospheric pressure, maintain high resonance quality factors in ambient conditions.
This enables chemisorption measurements in air at room temperature, with unprecedented mass resolution less than 1 attogram (10-18 g)