Acoustic focusing lens with near-zero refractive index based on coiling-up space structure

In this study, the application of thermal lens spectroscopy to detection of analytes in agarose gels was examined. It was found that a long-term refractive index gradient is produced in the sample, in addition to the thermally induced refractive index gradient, and gives rise to a long-term thermal lens signal. It is argued that the most likely source of the long-term signal is a concentration gradient formed in the sample. The long-term refractive index gradient results in a focusing lens, and is thus opposite to the thermal gradient. The formation of this gradient requires as much as 500 s to reach equilibrium during constant irradiation. The existence of the long-term refractive index gradient is verified by time-resolved Z-scan experiments. The signal resulting from this gradient is termed the long-term thermal lens and is shown to depend on temperature, is observed only for gelled agarose solutions, and is sensitive to anisotropies in the sample.

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A Sub-Wavelength Focusing Lens Composed of a Dual-Plate Metamaterial Providing a Negative Refractive Index

Journal of electromagnetic engineering and science ◽

10.5515/jkiees.2012.12.1.26 ◽

2012 ◽

Vol 12 (1) ◽

pp. 26-31 ◽

Cited By ~ 3

Author(s):

Dong-Ho Kim

Keyword(s):

Refractive Index ◽

Negative Refractive Index ◽

Dual Plate ◽

Focusing Lens ◽

Sub Wavelength

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UHV-TEM studies of laser-induced damage

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087471 ◽

1991 ◽

Vol 49 ◽

pp. 632-633

Author(s):

T.S. Savage ◽

R. Ai ◽

D. Dunn ◽

L.D. Marks

Keyword(s):

Surface Science ◽

Rapid Heating ◽

Local Heating ◽

Routine Practice ◽

Transmission Electron ◽

Northwestern University ◽

Laser Induced Damage ◽

Set Up ◽

Focusing Lens ◽

Diffusion Of Impurities

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.

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TEM characterization of proton-exchanged LiNbO3 optical waveguides

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014395x ◽

1986 ◽

Vol 44 ◽

pp. 480-481

Author(s):

W. E. Lee

Keyword(s):

Refractive Index ◽

Benzoic Acid ◽

Optical Waveguides ◽

Total Internal Reflection ◽

Index Of Refraction ◽

Optical Measurements ◽

Lithium Ions ◽

Wide Channel ◽

Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

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Light microscopy of ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015037x ◽

1993 ◽

Vol 51 ◽

pp. 908-909

Author(s):

Walter C. McCrone

Keyword(s):

Refractive Index ◽

Light Microscopy ◽

Light Microscope ◽

Polarized Light ◽

Refractive Indices ◽

Complete Coverage ◽

The Subject ◽

Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

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