The lock-in amplifier: A student experiment

Wolfson, Richard

doi:10.1119/1.16824

Cited by 38 publications

(19 citation statements)

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“…Pulsed illumination is a powerful method for improving the signal-to-noise ratio of optical signals [13]. By pulsing the light source on and off, one can in principle create images from which they can subtract a ‘dark frame’ (one with only the flame) from one with the flame and the narrow-spectrum illumination, resulting in an image which has only the illuminated target.…”

Section: Options To Further Improve the Techniquementioning

confidence: 99%

Imaging Through Fire Using Narrow-Spectrum Illumination

Smith

Hoehler

2018

Fire Technol

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This paper demonstrates a simple method to enhance visibility through clean-burning flames that allows new opportunities to perform qualitative and quantitative optical metrology in fire research. The method combines narrow-spectrum, blue illumination and matched optical filters to reduce the influence of optical emissions from a glowing hot target and a large natural gas diffusion flame. The paper describes how the required illumination strength and filtering can be estimated from basic combustion and optical principles. Compared to white light, the required illumination to detect objects 26 engulfed in flames with this method is reduced by a factor of 104. A series of experiments are conducted to determine the effectiveness of this method, successfully demonstrating the ability to take images of objects in natural gas fires up to 1000 kW using 200 W of illumination power.

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Section: Options To Further Improve the Techniquementioning

confidence: 99%

Imaging Through Fire Using Narrow-Spectrum Illumination

Smith

Hoehler

2018

Fire Technol

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“…O amplificador Lock-iné uma excelente ferramenta para medir sinais com pequenas amplitudes em sistemas imersos em ruído [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Neste caso, um Lock-in de 16 bits de resolução recebe um sinal do Chopper como referência e outro sinal do fotodector através do condicionador de sinais.…”

Section: Metodologiaunclassified

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Fauth¹,

Batista²

2018

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Resumo: Este trabalho apresenta a montagem de um polarímetro digital para medidas de atividadeóptica em modo pulsado. Em termos de instrumentação científica, foi desenvolvido um circuito eletrônico para medir a intensidade luminosa usando um fotodetector em conjunto com outros componentesópticos e um amplificador Lock-in. Além disso, um porta amostra foi projetado utilizando uma lente de quartzo acoplada em uma tampa e conectada a um tubo de PVC. O desempenho do sistema de medidasé investigado considerando a resolução e o limite de detecção a partir da determinação da rotaçãoóptica específica da sacarose. Este trabalho foi desenvolvido tendo como base o paradigma open source hardware e, portanto, toda a documentação estará disponível para que possa ser utilizada e aprimorada pela comunidade científica.Palavras chave: AtividadeÓptica, Polarímetro, Lock-in, Open Source Hardware. Abstract:This work presents the assembly of a digital polarimeter for measurements of optical activity in pulsed mode.In terms of scientific instrumentation, an electronic circuit was developed to measure light intensity using a photodetector in conjunction with other optical components and a Lock-in amplifier. In addition, a sample port was designed using a quartz lens attached to a cap and connected to a PVC pipe. The performance of the measurement system is investigated considering the resolution and the limit of detection from the determination of the specific optical rotation of sucrose. This work was developed based on the open source hardware paradigm and, therefore, all the documentation will be available so that it can be used and improved by the scientific community.

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“…Lock-in amplification and phase-sensitive detection are important techniques in experimental physics, see [1][2][3] for pedagogical uses of these techniques. Commerical devices are expensive and can be intimidating for new users.…”

Section: Introductionmentioning

confidence: 99%

Phase-sensitive detection in the undergraduate lab using a low-cost microcontroller

Schultz

2016

American Journal of Physics

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Phase-sensitive detection (PSD) is an important experimental technique that allows signals to be extracted from noisy data. PSD is also used in modulation spectroscopy and is used in the stabilization of optical sources. Commercial lock-in amplifiers that use PSD are often expensive and host a bewildering array of controls that may intimidate a novice user. Low-cost microcontrollers such as the Arduino family of devices seem like a good match for learning about PSD; however, making a self-contained device (reference signal, voltage input, mixing, filtering, and display) is difficult, but in the end the project teaches students "tricks" to turn the Arduino into a true scientific instrument.

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The lock-in amplifier: A student experiment

Cited by 38 publications

References 0 publications

Imaging Through Fire Using Narrow-Spectrum Illumination

Imaging Through Fire Using Narrow-Spectrum Illumination

Aparato experimental para medidas de atividade óptica da sacarose usando um amplificador Lock-in

Phase-sensitive detection in the undergraduate lab using a low-cost microcontroller

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