October 2019
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57 Reads
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11 Citations
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Publications (8)
October 2019
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115 Reads
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13 Citations
October 2018
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34 Reads
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3 Citations
March 2017
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351 Reads
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50 Citations
Optical Engineering
The continuous development of laser systems toward more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors, such as complementary metal-oxide-semiconductors (CMOS) and charge-coupled devices. These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, micro-optoelectromechanical systems, such as a digital micromirror device (DMD), are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources, both pulsed lasers and continuous-wave (CW)-lasers are used. The laser-induced damage threshold is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructive device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects, such as persistent dead columns or rows of pixels in the sensor image. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
October 2016
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51 Reads
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6 Citations
Proceedings of SPIE - The International Society for Optical Engineering
October 2016
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211 Reads
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13 Citations
Proceedings of SPIE - The International Society for Optical Engineering
May 2015
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37 Reads
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21 Citations
Optical Engineering
Electro-optical imaging sensors are widely distributed and used for many different tasks in military operations and civil security. However, their operational capability can be easily disturbed by laser radiation. The likeliness of such an incidence has dramatically increased in the past years due to the free availability of high-power laser pointers. These laser systems, offering laser powers of several watts, pose an increased risk to the human eye as well as to electro-optical sensors. An adequate protection of electro-optical sensors against dazzling is highly desirable. Such protection can be accomplished with different technologies; however, none of the existing technologies can provide a sufficient protection. All current protection measures possess individual advantages and disadvantages. We present the results on the performance of two different protection technologies. The evaluation is based on automatic optical pattern recognition of sensor images taken from a scene containing triangles.
October 2014
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9 Reads
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2 Citations
Proceedings of SPIE - The International Society for Optical Engineering
In this paper, we propose ways to study the optical limiting behavior of dissolved nanoparticles. We want to present two different approaches. First, we identify the key properties responsible for the critical fluence threshold using a principal component analysis. For metallic nanoparticles, we found that the real part of the complex dielectric function must have a negative value as low as possible, while the imaginary part must be close to zero. Additionally, the solvent should have a low refractive index as well as a low absorption. Furthermore, nonlinear scattering seems to be an important limiting mechanism for nanoparticle limiters. Here, we present a thermal finite element model to predict the temporal evolution of the temperature profile in the nanoparticles and their vicinity. The temperature profile leads to vapor bubbles around the nanoparticles and Mie theory is used to calculate the induced scattering. We demonstrate the functionality of the model by simulating an Au-nanoparticle in an ethanol solution.
Citations (8)
... where and are the laser irradiance and the saturation level, respectively. Based on results for visible light using a CMOS camera [28,29] a minimum average irradiance of 50 mW/cm during each row exposure is required, and at least 0.1 mW/cm pick irradiance to achieve dazzling with shorter pulses. We experimentally found that similar conditions hold for the camera used in this work, as observed in Figure 2. ...
- Citing Conference Paper
October 2019
... Besides, there is a wide span of damage threshold in Table. 1, which is mainly due to different experimental scenarios (eg. 10 s irradiation time in Ref. [10] or single shot in most of the other references) and different criteria for the damage threshold. [16,17] Theoretically, the silicon-based camera is considered to have no response to 1550 nm. However, there have been reported cases of 1550 nm LiDAR burning out cameras. ...
- Citing Conference Paper
October 2019
... Moreover, weather conditions and the course of sun are hardly reproducible for multiple imagers and the acquired data is highly dependent on used devices. Another approach without these drawbacks is imager assessment by lab measurements, which use a scene projector with user-defined input images, see for instance [1]. In order to evaluate the impact of turbulence and in particular to assess imagers with embed digital turbulence mitigation techniques [2], a fast and reliable image-based turbulence simulation is required to generate appropriate input images. ...
- Citing Conference Paper
October 2018
... [1][2][3][4]. Nevertheless, exposure to high-power CW lasers poses the risk of causing irreversible damage to sensitive optical components or human eyes; e.g., the CW laser-induced damage threshold for most common metal oxide semiconductor detectors is generally in the range of tens of kW/cm 2 [5]. Consequently, it is of great significance to research and develop effective laser protection methods with low optical limiting thresholds. ...
- Citing Article
March 2017
Optical Engineering
... Microassembly technologies and systems can be used to realize microassembly and micromanipulation of microparts and its systems; they are widely used in microassembly and manufacturing of MEMS, which are composed of heterogeneous microparts with different scales, such as inertial confinement fusion (ICF) target [1,2], micro sensor [3], microfluidic chip [4], acceleration switch [5], and micro-optic-electromechanical system (MOEMS) [6,7], and their research and development are key link to new generation manufacturing and intelligent manufacturing [8]. However, the dimension scale of microparts and their systems to be microassembled and processed with highprecision spans at least two scales in nanoscale, micron scale, millimeter scale, or even centimeter scale. ...
- Citing Conference Paper
October 2016
Proceedings of SPIE - The International Society for Optical Engineering
... Therefore, a camera reflecting the functioning of the human eye could be a solution during such tests. This idea has been proposed by Korber and Eberle [41]. The authors presented the efforts of designing and planning their human eye camera but the prototype is still not completed. ...
- Citing Conference Paper
October 2016
Proceedings of SPIE - The International Society for Optical Engineering
... Since this goal is difficult to achieve, we have focused the experimental and theoretical work on laser protection at our institute on two main topics: (1) hardening of optical systems to protect the human eye or sensors against laserinduced damage. 2 Here, we developed and tested optical power limiters utilizing the nonlinear optical response of nanoparticles. 3,4 (2) Hardening of imaging sensors against laser dazzling. We designed an active protection concept based on a digital micromirror device (DMD) in combination with wavelength multiplexing. ...
- Citing Article
October 2014
Proceedings of SPIE - The International Society for Optical Engineering
... The irradiation effects of lasers on detectors can be classified as photoelectric effects and material thermal effects [1][2][3]. As the energy of laser dazzling continues to increase, saturation, saturation crosstalk, and over-saturation phenomena can be observed in the images [4][5][6]. ...
- Citing Article
May 2015
Optical Engineering