Interferometric detection of forward scattered light from small particles

Batchelder, J. S.; Taubenblatt, M. A.
July 1989
Applied Physics Letters;7/17/1989, Vol. 55 Issue 3, p215
Academic Journal
The detection of subtenth micron particles in processing fluids is a critical and growing need in the semiconductor industry. In this letter, we show that a small dielectric particle in a focused monochromatic light beam produces a scattered wave (Rayleigh scattering) in please quadrature with the far-field incident beam, therefore causing a phase shift in this beam. Thus, the forward scattered field due to the particle may be detected using a bright field interferometer. This allows detection which is near shot noise limited even for very small particles, and measures the sign of the scattered field as well, such that particles may be distinguished from bubbles. We describe an appropriate interferometer design based on Nomarski optics, which we have used to verify our calculation, measuring scattering in water from single polystyrene spheres as small as 0.038 µm in diameter.


Related Articles

  • Multi-beam multi-wavelength semiconductor lasers. Nanfang Yu; Kats, Mikhail; Pflügl, Christian; Geiser, Markus; Qi Jie Wang; Belkin, Mikhail A.; Capasso, Federico; Fischer, Milan; Wittmann, Andreas; Faist, Jérôme; Edamura, Tadataka; Furuta, Shinichi; Yamanishi, Masamichi; Kan, Hirofumi // Applied Physics Letters;10/19/2009, Vol. 95 Issue 16, p161108 

    Multibeam emission and spatial wavelength demultiplexing in semiconductor lasers by patterning their facets with plasmonic structures is reported. Specifically, a single-wavelength laser was made to emit beams in two directions by defining on its facet two metallic gratings with different...

  • Orthogonal Dual-Frequency SOA-Fiber Laser. Yoshitaka Takahashi; Yudai Fukaya; Sho Takahashi // Key Engineering Materials;2014, Vol. 596, p129 

    In order to develop a new orthogonal dual-frequency laser, we studied a fiber ring laser using a SOA (semiconductor optical amplifier) and aim to apply it to a novel light source for optical heterodyne interferometry. The frequency difference was generated by a linear or circular birefringent...

  • Interferometry helps optimize high-brightness LED production. Dong Chen; Novak, Erik; Blewett, Nelson // Laser Focus World;Sep2010, Vol. 46 Issue 9, p35 

    The article discusses the functionality of optical interferometric profilometry to measure and monitor high-brightness light emitting diode (HB-LED) wafer surfaces in 3D detail. It notes the importance of patterned sapphire substrates (PSS) to improve LED performance and to be used in HB-LED...

  • Dynamic spectral interferometry for measuring the nonlinear amplitude and phase response of a saturable absorber mirror. Stibenz, Gero; Steinmeyer, Günter; Richter, Wolfgang // Applied Physics Letters;2/21/2005, Vol. 86 Issue 8, p081105 

    We report on spectral interferometry for measuring the spectrally resolved nonlinear phase and amplitude response in a pump–probe experiment. Using nJ pulses from a femtosecond oscillator, we demonstrate the method by measuring the nonlinear response of a GaAs/AlGaAs single-quantum-well...

  • Theory of coherent phenomena in pump-probe excitation of semiconductor amplifiers. Girndt, A.; Knorr, A.; Hofmann, M.; Koch, S. W. // Journal of Applied Physics;9/1/1995, Vol. 78 Issue 5, p2946 

    Addresses the pump-probe signal of a two band semiconductor amplifier. Application of Maxwell-Semiconductor-Bloch equations; Need of interferometric precision for the pump-probe experiments; Details of the model of the semiconductor amplifier and treatment of the probe technique.

  • Interferometers measure distance with light. Peach, Laurie Ann // Laser Focus World;May97, Vol. 33 Issue 5, p159 

    Focuses on the use of interferometry techniques to capitalize on the principle of interference and the wave-like nature of light for measuring microscopic distances. Background history of interferometers; Wave theory of light; Fringe patterns; Encoding of wavefront phase in the variations in...

  • Three-dimensional position detection of optically trapped dielectric particles. Rohrbach, Alexander; Stelzer, Ernst H. K. // Journal of Applied Physics;4/15/2002, Vol. 91 Issue 8, p5474 

    A theory is presented together with simulation results that describe three-dimensional position detection of a sphere located in a highly focused beam by back-focal plane interferometry. This technique exploits the interference of scattered and unscattered light, which is projected on a quadrant...

  • Simultaneous measurement of substrate temperature and thin-film thickness on SiO2/Si wafer using optical-fiber-type low-coherence interferometry. Ohta, Takayuki; Koshimizu, Chishio; Kawasaki, Kanta; Takeda, Keigo; Ito, Masafumi // Journal of Applied Physics;Jan2009, Vol. 105 Issue 1, p013110 

    This paper proposes a technique for simultaneously monitoring the thickness of a SiO2 thin film and the temperature of a Si substrate. This technique uses low-coherence interferometry and has the potential to be used for online monitoring of semiconductor manufacturing processes. In...

  • Electroluminescent properties of chemically synthesized zinc sulfide nanocrystals doped with manganese. Adachi, Daisuke; Hama, Takeshi; Toyama, Toshihiko; Okamoto, Hiroaki // Journal of Materials Science: Materials in Electronics;Jan2009 Supplement 1, Vol. 20, p130 

    High-field electroluminescence (EL) of chemically synthesized ZnS:Mn nanocrystals with a crystallite size of 4 nm was investigated using a device consisting of glass substrate/indium–tin oxide/ZnS:Mn NC emission layer/Al. For electric fields over ca. 1 MV/cm, the current was turned on,...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics