Measurement of Parallelism of the Surfaces of a Transparent Sample Using Two-Beam Nonlocalized Fringes Produced by a Laser

Wasilik, J H; Blomquist, T.; Willett, Colin S.

doi:10.1364/ao.10.002107

Cited by 17 publications

(6 citation statements)

References 5 publications

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“…The Pohl configuration offers a simple, quick and efficient approach for measuring the wavelength [38]. It has been applied for shop testing conditions, phase measurement and parallelism measurement of transparent surfaces [80][81] [82]. For sensing applications, a simple Pohl configuration is constructed by depositing a sensing film on a substrate.…”

Section: Pohl Interferometermentioning

confidence: 99%

A review of optical interferometry techniques for VOC detection

Khan

Calvé

Newport

2020

Sensors and Actuators A: Physical

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Exposure to volatile organic compounds (VOCs) is widely associated with adverse health effects.Detection and monitoring of VOCs are important for maintaining safe and healthy industrial and domestic environments. Interferometry is a highly-sensitive optical measurement technique that has been widely applied to a vast range of physical parameters from the speed of light to temperature and has also been used to detect VOCs at the sub-ppm range. Owing to the vast range of interferometer arrangements and processing techniques, this review assesses the different approaches adopted in detecting VOCs. Different interferometry arrangements including the Fabry-Perot interferometry, Sagnac interferometry and Mach-Zehnder interferometry are reviewed for VOC detection, including the different sensing films and materials employed. We present the basis of each technique, applications and limitations. The different interferometry techniques are summarized by comparing the sensitivity, limit of detection, linearity, response time and the challenges of current interferometry techniques.Lastly, prospects to realize a miniaturized, high-sensitive and multiplex interferometric sensors based on the recent technology are suggested.

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Section: Pohl Interferometermentioning

confidence: 99%

A review of optical interferometry techniques for VOC detection

Khan

Calvé

Newport

2020

Sensors and Actuators A: Physical

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“…Although a very simple interference device, it has been used for performing sensitive optical characterizations like phase measurement [15]. Its versatility has been proven in shop testing conditions as well as while measuring the parallelism of transparent surfaces [16,17]. Unlike other interferometry devices [18], not needing very special optical components, it can very easily be incorporated in undergraduate laboratories as a wavelength measuring device.…”

Section: Pohl Interferometer: Principle and Details Of Measurementmentioning

confidence: 99%

Construction of an inexpensive molecular iodine spectrometer using a self-developed Pohl wavemeter around 670 nm wavelength

Barthwal¹,

Vudayagiri²

2015

Eur. J. Phys.

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We describe construction of an inexpensive Iodine Spectrometer with a home made Iodine vapour cell and a self developed wavemeter based on Pohl Interferometer, around 670 nm wavelength.This can be easily realised in an undergraduate teaching laboratory to demonstrate use of a diode laser interferometry using a Pohl interferometer and measurement of wavelength using image processing techniques.Visible alternative to the IR diode lasers, 670 nm diode laser used here give chance to undergraduate students to perform comprehensive though illustrative atomic physics experiments including the Zeeman effect, the Hanle effect, Magneto Optic Rotation (MOR) effect with a little tweaking in the present spectrometer. The advantage of the spectrometer is its ease of construction with readily available optics, electronics, evacuation and glass blowing facilities and easy analysis algorithm to evaluate the wavelength. The self developed algorithm of raster scanning and circular averaging gives the researcher insight into the basics of image processing techniques. Resolution approaching 0.5 nm can be easily achieved using such simple setup.

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“…Unsteady heat flow via the step-temperature excitation setup all isothermal surfaces (between T 0 and T i ) in motion. The moving temperature point 'T' which satisfies equations (11), (15) and ( 16) (2η 2 is unity), is called the ETP. The group of ETPs forms a moving isothermal surface called the 'effective isothermal surface (EIS)'.…”

Section: Defining T T Tmentioning

confidence: 99%

Position-dependent velocity of an effective temperature point for the estimation of the thermal diffusivity of solids

Balachandar¹,

Shivaprakash²,

Rao³

2015

Meas. Sci. Technol.

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A new approach is proposed to estimate the thermal diffusivity of optically transparent solids at ambient temperature based on the velocity of an effective temperature point (ETP), and by using a two-beam interferometer the proposed concept is corroborated. 1D unsteady heat flow via step-temperature excitation is interpreted as a ‘micro-scale rectilinear translatory motion’ of an ETP. The velocity dependent function is extracted by revisiting the Fourier heat diffusion equation. The relationship between the velocity of the ETP with thermal diffusivity is modeled using a standard solution. Under optimized thermal excitation, the product of the ‘velocity of the ETP’ and the distance is a new constitutive equation for the thermal diffusivity of the solid. The experimental approach involves the establishment of a 1D unsteady heat flow inside the sample through step-temperature excitation. In the moving isothermal surfaces, the ETP is identified using a two-beam interferometer. The arrival-time of the ETP to reach a fixed distance away from heat source is measured, and its velocity is calculated. The velocity of the ETP and a given distance is sufficient to estimate the thermal diffusivity of a solid. The proposed method is experimentally verified for BK7 glass samples and the measured results are found to match closely with the reported value.

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Measurement of Parallelism of the Surfaces of a Transparent Sample Using Two-Beam Nonlocalized Fringes Produced by a Laser

Cited by 17 publications

References 5 publications

A review of optical interferometry techniques for VOC detection

A review of optical interferometry techniques for VOC detection

Construction of an inexpensive molecular iodine spectrometer using a self-developed Pohl wavemeter around 670 nm wavelength

Position-dependent velocity of an effective temperature point for the estimation of the thermal diffusivity of solids

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