A novel linearity tester for optical detectors using high-brightness light emitting diodes

Shin, Dayeon; Lee, Dong‐Hoon; Park, Chul-Woung; Park, Seung-Nam

doi:10.1088/0026-1394/42/2/011

Cited by 16 publications

(17 citation statements)

References 4 publications

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“…We have developed a new theory [15] to explain the cause of this early onset of optical saturation behaviour which allows us to confirm that a negligible amount of optical pumping occurred in the experiments reported here. In contrast to previous models [17,25,26] that approximate the atom as a two-level system under uniform illumination, we developed a theory for multi-level atoms probed by a beam with finite spatial extent [15]. This better captures the physical properties and situation of this Rb experiment.…”

Section: Estimation Of Systematic Uncertaintiesmentioning

confidence: 99%

“…In this study, we chose Rb which has a high optical cross section, ensuring that the absorption signal-to-noise is satisfactory in spite of the very low vapor density. This choice also gives the ability to operate in a range where high quality lasers are readily available and where silicon detectors, with their extremely good linearity [17] and quantum efficiency, can be used. At room temperature, it was possible to use a smaller cell than those in the molecular experiments for the same absorption depth, which was convenient for thermal control.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative atomic spectroscopy for primary thermometry

et al. 2011

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Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in 85 Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine kB with a relative uncertainty of 4.1 × 10 −4 , and with a deviation of 2.7 × 10 −4 from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured kB value was less than 4 × 10 −6 . The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments.

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Section: Estimation Of Systematic Uncertaintiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative atomic spectroscopy for primary thermometry

et al. 2011

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“…Analysis of the combinatorial signal data by the alternative two-lamp flux addition method [7–9] is particularly illuminating, and this small subsection briefly highlights the differences between the two analysis methods. Our main objective here is to show that the simple two-lamp flux addition analysis is inconsistent with the combinatorial results (and by extension the light bias dependent EQE) and does not predict the true nonlinearity of the solar cells.…”

Section: Measurement Results and Discussionmentioning

confidence: 99%

“…Another involves measurements of nonlinearity with respect to a linear device [6]. A more common method includes the flux addition principle using a dual light source approach, i.e., the two-lamp method [7–9] or the double-aperture method [10]. The first technique, in principle allows for the determination of the actual mathematical relationship between the signal and the flux and can furthermore be used to obtain the I sc under a given light spectrum for nonlinear cells through an iterative integration calculation [2].…”

Section: Introductionmentioning

confidence: 99%

Non-linearity measurements of solar cells with an LED-based combinatorial flux addition method

et al. 2016

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We present a light emitting diode (LED)-based system utilizing a combinatorial flux addition method to investigate the nonlinear relationship in solar cells between the output current of the cell and the incident irradiance level. The magnitude of the light flux is controlled by the supplied currents to two LEDs (or two sets of them) in a combinatorial fashion. The signals measured from the cell are arranged within a related overdetermined linear system of equations derived from an appropriately chosen Nth degree polynomial representing the relationship between the measured signals and the incident fluxes. The flux values and the polynomial coefficients are then solved for by linear least squares to obtain the best fit. The technique can be applied to any solar cell, under either monochromatic or broadband spectrum. For the unscaled solution, no reference detectors or prior calibrations of the light flux are required. However, if at least one calibrated irradiance value is known, then the entire curve can be scaled to an appropriate spectral responsivity value. Using this technique, a large number of data points can be obtained in a relatively short time scale over a large signal range.

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“…[26,27]. By combining three lasers, two of nearly equal optical power and a third simulating the background level, we are able to simulate absorption features with four precisely known depths by cycling through four possible states of the equal power lasers (on:off, on:on, off:on, off:off).…”

mentioning

confidence: 99%

Absolute absorption line-shape measurements at the shot-noise limit

et al. 2012

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Here, we report a measurement scheme for determining an absorption profile with an accuracy imposed solely by photon shot noise. We demonstrate the power of this technique by measuring the absorption of cesium vapor with an uncertainty at the 2-ppm level. This extremely high signal-to-noise ratio allows us to directly observe the homogeneous line-shape component of the spectral profile, even in the presence of Doppler broadening, by measuring the spectral profile at a frequency detuning more than 200 natural linewidths from the line center. We then use this tool to discover an optically induced broadening process that is quite distinct from the well-known power broadening phenomenon. The recent development of the optical frequency comb [1,2] has delivered a powerful new tool for absorption spectroscopy. The frequency comb allows us to determine the optical frequency of spectral features to astonishing new levels, which has paved the way for intriguing laboratory-scale tests of fundamental physics [3] as well as exciting applications in a wide variety of fields, including frequency metrology [1,4], direct optical frequency comb spectroscopy [5][6][7], and trace gas detection [8,9]. High-quality frequency measurement, however, represents only half the story. Many spectroscopic applications also demand absorbance measurements of high precision and accuracy in order to reveal subtle features of the spectral line shape. This requirement is of particular concern to the fields of precision line-shape measurement [10,11], precision line-shape analysis [12], and Doppler thermometry [13][14][15][16].The conventional quantum limit for precision in laser absorption spectroscopy (LAS) is set by shot noise of the probing light. In practice, though, this performance level has been exceedingly difficult to achieve because technical noise and instrumental limitations usually mask this quantum limit. These technical limitations are particularly acute for LAS because it is inherently a bright field [17] measurement; i.e., the absorbance is encoded in the ratio of two measurements of the incident and transmitted power. If one wishes to build a highly sensitive and accurate tool for probing optical absorbance, then there are three key challenges to overcome: First, one needs to suppress technical noise sources, which are usually much larger than fundamental sources; second, the resolution of the measurement can be limited because most of the dynamic range of the sensor is consumed in measuring small changes of relatively large signals; and third, the measurement technique needs to be inherently linear.

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A novel linearity tester for optical detectors using high-brightness light emitting diodes

Cited by 16 publications

References 4 publications

Quantitative atomic spectroscopy for primary thermometry

Quantitative atomic spectroscopy for primary thermometry

Non-linearity measurements of solar cells with an LED-based combinatorial flux addition method

Absolute absorption line-shape measurements at the shot-noise limit

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