• Medical Lasers
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• v.10 no.2
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• pp.68-75
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• 2021

Medical lasers have been widely used for various diseases. Despite the notable benefits, lasers could cause several complications such as skin burn, eye injury, airway fire, and so on. These accidents may occur not only with patients, users of the laser, or laser handlers but also to people passing in front of the laser treatment room. Although there is a risk associated with the laser, most of them can be prevented through good training, use of proper protection equipment, and ensuring the safe operation of the laser at all times. Due to the increasing use of lasers and the growing interest in their use, medical institutions should particularly emphasize the safe use of lasers and introduce systems for laser safety.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.106-109
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• 2004

In this project, we have developed the eye-safe LRF system of 1.54 ${\mu}{\textrm}{m}$ wavelength using OPO. The maximum measured distance was 3.7km in outdoor experiment. We used Nd：YAG (1064nm) as a laser medium. It was applied BBO to construct the system. We also developed a time-counter for the range finder using a method of TOF (time of flight). The counter-clock used at the time counter was 320MHz making resolution within $\pm$1m. Start and stop signals were detected by two channel systems using PIN and APD. The LRF's repetition rate was 4 times per minute. The energy was measured to be over 9mJ. And, pulse-duration was 23ns. Resolution was $\pm$2m at the distance measurement using a target.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.116-117
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• 2002

In recent years, there has been an increasing interest in $Tm^{3+}$ doped crystals and glasses due to their potential applications as near infrared lasers and infrared to visible upconversion lasers for use in different fields such as medical surgery, eye safe laser radar, data storage, barcode reading and so on. Thulium ions have stable excited levels suitable for emitting blue upconversion fluorescence. (omitted)

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.295-305
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• 2018

We present a passively Q-switched monolithic Er:Yb:glass microchip laser developed in our lab. The microchip laser can produce pulses at 1535 nm of the 'eye-safe' wavelengths with the pulse energy of 50 uJ and the pulse width of 4-6 ns. Using the laser we also designed and developed a pulsed Er:Yb:glass microchip laser rangefinder. Expressions for background and signal power, noise, and signal-to-noise ratio are reviewed. A computer simulation was used to optimize laser power, receiver aperture, and preamplifier bandwidth for the efficient system design of the laser rangefinder. Experimental results are presented to compare with the theory.

• Ceramist
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• v.21 no.2
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• pp.59-74
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• 2018

Imaging in the Short Wave Infrared (SWIR) provides several advantages over the visible and near-infrared regions: enhanced image resolution in in foggy or dusty environments, deep tissue penetration, surveillance capabilities with eye-safe lasers, assessment of food quality and safety. Commercially available SWIR imagers are fabricated by integrating expensive epitaxial grown III-V compound semiconductor sensors with Si-based readout integrated circuits(ROIC) by indium bump bonding Infrared image sensors made of solution-processed quantum dots have recently emerged as candidates for next-generation SWIR imagers. They combine ease of processing, tunable optoelectronic properties, facile integration with Si-based ROIC and good performance. Here, we review recent research and development trends of various application fields of SWIR image sensors and nano-materials capable of absorption and emission of SWIR band. With SWIR sensible nano-materials, new type of SWIR image sensor can replace current high price SWIR imagers.

• Journal of Sensor Science and Technology
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• v.33 no.2
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• pp.93-97
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• 2024

With the development of promising future mobility and urban air mobility (UAM) technologies, the demand for LIDAR sensors has increased. The SWIR photodetector is a sensor that detects lasers for the 3D mapping of lidar sensor and is the most important technology of LIDAR sensor. An SWIR photodetector based on QDs in an eye-safe wavelength band of over 1400 nm has been reported. QDs-based SWIR photodetectors can be synthesized and processed through a solution process and have the advantages of low cost and simple processing. However, the organic ligands of QDs have insulating properties that limit their ability to improve the sensitivity and stability of photodetectors. Therefore, the technology to replace organic ligands with inorganic ligands must be developed. In this study, the organic ligand of the synthesized PbS QDs was replaced with a MAPI inorganic ligand, and an SWIR photodetector was fabricated. The analysis of the characteristics of the manufactured photodetector confirmed that the photodetector based on MAPI-capped PbS QDs exhibited up to 26.5% higher responsivity than that based on organic ligand PbS QDs.

• Journal of Sensor Science and Technology
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• v.32 no.5
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• pp.285-289
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• 2023

Recently, the demand for lidar systems for autonomous driving is increasing, and research on Shortwave Infrared(SWIR) photodetectors for this purpose is being actively conducted. Most SWIR photodetectors currently being developed are based on InGaAs, and have the disadvantages of complex processes, high prices, and limitations in research due to monopoly. In addition, current SWIR photodetectors use lasers in the 905 nm wavelength band, which can pass through the pupil and cause damage to the retina. Therefore, it is required to develop a SWIR photodetector using a wavelength band of 1400 nm or more to be safe for human eyes, and to develop a material that can replace the proprietary InGaAs. PbS QDs are group 4-6 compound semiconductors whose absorption wavelength band can be adjusted from 1000 to 2700 nm, and have the advantage of being simple to process. Therefore, in this study, PbS QDs having an absorption wavelength peak of 1415 nm were synthesized, and a SWIR photodetector was fabricated using this. In addition, the photodetector's responsivity was improved by applying P3HT and ZnO NPs to improve electron hole mobility. As a result of the experiment, it was confirmed that the synthesized PbS QDs had excellent FWHM characteristics compared to commercial PbS QDs, and it was confirmed that the photodetector had a maximum current change of about 1.6 times.