Engineers develop new sensor to detect tiny #individual #nanoparticles Scientists have developed a new sensor that can detect and count nanoparticles, at sizes as small as 10 nanometers, 1 at a time. It could potentially detect much smaller particles, viruses and small molecules. Yang et al have created #Raman #microlaser sensor in a SiO2 chip to find individual nanoparticles without the need to dope the chip with chemicals called rare-earth ions to provide optical gain for the microlaser. Using the Raman process loosens the requirement of specific wavelength bands for pump lasers. #METHOD: they integrated Raman lasing in a silica microcavity with their mode splitting technique to develop a new, powerful sensor that more readily detects nanoparticles. The technology will benefit the electronics, acoustics, biomedical, plasmonics, security and metamaterials fields. >>Yangs microsensor is in a class called #whispering #gallery #mode #resonators (WGMRs) (it works similarly to renowned whispering gallery in Londons St. Pauls Cathedral, where a person on one side of the dome can hear a message spoken to the wall by another person on the other side. The device does much the same thing with #light #frequencies rather than audible ones.) >>When a Raman laser beam is generated in the resonator, it likely will encounter a particle, such as a virus nanoparticle, on the circle. When the beam initially sees the particle, the beam splits into 2, generating two lasing lines that serve as reference to the other to form a self-referenced sensing technique. #CONC: In addition to Raman microlasers for #particle #sensing, there is possibility of using intrinsic gain mechanisms, such as Raman and #parametric #gain, instead of optical dyes, rare-earth ions or quantum dots, for loss compensation in optical and plasmonic systems where dissipation hinders progress and limits applications. news.wustl.edu/news/Pages/27295.aspx
Posted on: Tue, 02 Sep 2014 15:14:00 +0000
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