Simple differential lock‐in amplifier for optical measurements

Abstract Rheo-optics is a method that allows the analysis of optical properties, like birefringence and dichroism under steady and oscillatory shear. It is possible to correlate macroscopic mechanical responses with induced microscopic changes in the material. We describe how this method was improved several fold and implemented on a commercially available setup. However, the here presented ideas are applicable to any rheo-optical setup, based on modulation of the laser light. Additionally it does not need a lock-in amplifier and therefore reduces the costs of the setup.

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Broadband stimulated Raman scattering microscopy at >1 frame/s with a multi-channel integrated-circuit differential lock-in amplifier

Advanced Chemical Microscopy for Life Science and Translational Medicine 2021 ◽

10.1117/12.2577680 ◽

2021 ◽

Author(s):

Alejandro De la Cadena ◽

Andrea Ragni ◽

Giuseppe Sciortino ◽

Federico Vernuccio ◽

Carlo Valensise ◽

...

Keyword(s):

Raman Scattering ◽

Integrated Circuit ◽

Stimulated Raman Scattering ◽

Differential Lock ◽

Lock In ◽

Stimulated Raman

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Resolution enhancement in Brillouin optical correlation domain analysis by differential lock-in detection

10.1117/12.974973 ◽

2012 ◽

Author(s):

Ji Ho Jeong ◽

Kwanil Lee ◽

Kwang Yong Song ◽

Je-Myung Jeong ◽

Sang Bae Lee

Keyword(s):

Resolution Enhancement ◽

Domain Analysis ◽

Optical Correlation ◽

Differential Lock ◽

Lock In

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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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