• 제목/요약/키워드: Laser system

검색결과 3,640건 처리시간 0.037초

대출력 Gauss형 Nd:글라스 레이저 비임의 증폭특성에 관한 연구 (A Study on the Amplification Characteristics of High-Power Gaussian Nd:Glass Laser Beam)

  • 강형부;장용무
    • 대한전기학회논문지
    • /
    • 제36권10호
    • /
    • pp.741-747
    • /
    • 1987
  • The high-power Nd:glass system with five-stage amplifier was designed and its amplification characteristics was studied for developing high-power Nd:glass laser system as an energy driver of inertial confinement fusion(ICF). In order to study the amplification characteristics of remporal and spacial Gaussian laser beam, the dependence of them on pumping efficiency and rod loss were studied and discussed. The output energy of this system using phosphate Nd glass rod(LHG-7,LHG-8) and silicate Nd glass rod(LSG-91H), respectively, was calculated by the computer simulation using Avizonis-Grotbeck and Frantz Nodvik equations. As results of this simulation, it was found that the shorter the risetime of laser pulse, the larger the amplification factor and that the larger peak value of laser pulse, the lower the amplification factor. The output inergies of 179J, 344J, and 7J were obtained by the designed five-stage amplified high-power Nd:glass laser system using glass rods of LHG-7,LHG-8, and LSG-91H, respectively. From the results it was found that the laser system using the LHG-8 glass rod was the most excellent one among the systems and the cross section for stimulated emission of the gain coefficient was essentially important parameter for the amplification characteristics.

  • PDF

High-speed angular-scan pulse-echo ultrasonic propagation imager for in situ non-destructive evaluation

  • Abbas, Syed H.;Lee, Jung-Ryul
    • Smart Structures and Systems
    • /
    • 제22권2호
    • /
    • pp.223-230
    • /
    • 2018
  • This study examines a non-contact laser scanning-based ultrasound system, called an angular scan pulse-echo ultrasonic propagation imager (A-PE-UPI), that uses coincided laser beams for ultrasonic sensing and generation. A laser Doppler vibrometer is used for sensing, while a diode pumped solid state (DPSS) Q-switched laser is used for generation of thermoelastic waves. A high-speed raster scanning of up to 10-kHz is achieved using a galvano-motorized mirror scanner that allows for coincided sensing and for the generation beam to perform two-dimensional scanning without causing any harm to the surface under inspection. This process allows for the visualization of longitudinal wave propagation through-the-thickness. A pulse-echo ultrasonic wave propagation imaging algorithm (PE-UWPI) is used for on-the-fly damage visualization of the structure. The presented system is very effective for high-speed, localized, non-contact, and non-destructive inspection of aerospace structures. The system is tested on an aluminum honeycomb sandwich with disbonds and a carbon fiber-reinforced plastic (CFRP) honeycomb sandwich with a layer overlap. Inspection is performed at a 10-kHz scanning speed that takes 16 seconds to scan a $100{\times}100mm^2$ area with a scan interval of 0.25 mm. Finally, a comparison is presented between angular-scanning and a linear-scanning-based pulse-echo UPI system. The results show that the proposed system can successfully visualize defects in the inspected specimens.

레이저 간섭계를 이용한 이동형 미세 변위 측정에 관한 연구 (A Study on the Portable Micro Displacement Measurement Using Laser Interferometer)

  • 최경현;양형찬
    • 동력기계공학회지
    • /
    • 제10권2호
    • /
    • pp.99-103
    • /
    • 2006
  • The laser interferometer has been used for measurement of the micro displacement error. Although the laser interferometer is widely accepted as a tool for measurement of motion accuracy, the set-up procedure is time-consuming because of the strict requirement on alignment between a laser head and optic units. This paper addresses the development of a laser interferometer to measure the micro displacement for a micro machine. The portable laser interferometer which integrates a laser probe and optics, is developed for the convenient measurement. For the experiment, moving mirror set up on the micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is obtained and analyzed by LabView. Finally experiments are found out the relation between micro displacement and output signal.

  • PDF

고출력 $CO_2$ 레이저 용접시 포토 다이오드를 이용한 플라즈마와 스패터 모니터링 (Monitoring of plasma and spatter with photodiode in $CO_2$ laser welding)

  • 박현성;이세헌;정경훈;박인수
    • 한국레이저가공학회지
    • /
    • 제2권1호
    • /
    • pp.30-37
    • /
    • 1999
  • Laser-welded Tailored Blank is the hottest thing in many automobile companies. But they demand on weld quality, reproducibility, and formability. So it is the great problem of automation of laser welding process. Therefore, it is requested to construct on-line process monitoring system on high accuracy. The light which is emitted from plasma and spatter in laser welding was detected by photo-diodes. It was found that the light intensity depends on welding speed. laser power, and flow rate of assist gas. The relationship between the plasma and spatter and the weld quality can be used for on-line laser weld monitoring systems.

  • PDF

고점성 청동분말을 이용한 알루미늄 합금의 레이저 클래딩 특성 (Characteristic of Laser Cladding Process with High Viscosity Bronze Powder and Al-alloy)

  • 오동수;전병철;김재도
    • 한국레이저가공학회:학술대회논문집
    • /
    • 한국레이저가공학회 2001년도 춘계학술발표대회 논문개요집
    • /
    • pp.31-34
    • /
    • 2001
  • Laser cladding Processing allows rapid transfer of heat to the material being minimum conduction into base metal. The effects of CO$_2$ laser cladding with high powder were investigated. High viscosity bronze powder consists of bronze powder used at a high temperature. The material has a high viscosity So that it can be substrate. Therefore. Laser cladding can be processed on a curved or slope surface. CO$_2$ laser cladding was designed It consists of the high viscosity bronze powder the shielding gas system and the preheating system The high viscosity powder properly at 0.3g/s and 0.50g/s. Because of the metallic bond between bronze per the hardness of dilution layer was suddenly increased. Experimental as results viscosity mixed powder can be a useful cladding material.

  • PDF

$CO_2$ Laser Absorption Measurement of $CH_3CH_2Br$ using Photoacoustic Method

  • Jang Soo Shin;Kyung Hoon Jung;Cheol Jung Kim
    • Bulletin of the Korean Chemical Society
    • /
    • 제13권5호
    • /
    • pp.553-556
    • /
    • 1992
  • The ${CO}_2$ laser absorption measurement of ${CH}_3{CH}_2Br$ utilizing photoacoustic (PA) technique was performed using a cw and a pulsed ${CO}_2$ lasers. The absorption profile in the ${CO}_2$ laser wavelength region (9-10 ${\mu}$m) and the macroscopic small signal absorption cross section at 10P(20) (10.59 ${\mu}$m, 944 $cm^{-1}$) laser line were measured using a cw ${CO}_2$ laser. The laser fluence dependence on infrared multiphoton absorption (IRMPA) was also studied with a pulsed TEA ${CO}_2$ laser at 10P(20) laser line. In view of monotonic increase of PA signal with the rise of laser fluence, it was suggested that the anharmonicity in pumped vibration mode did not restrict ir multiphoton absorption in ${CH}_3{CH}_2Br$ system as found in large molecular system.

Characteristics of Relative Navigation Algorithms Using Laser Measurements and Laser-GPS Combined Measurements

  • Kang, Dae-Eun;Park, Sang-Young;Son, Jihae
    • Journal of Astronomy and Space Sciences
    • /
    • 제35권4호
    • /
    • pp.287-293
    • /
    • 2018
  • This paper presents a satellite relative navigation strategy for formation flying, which chooses an appropriate navigation algorithm according to the operating environment. Not only global positioning system (GPS) measurements, but laser measurements can also be utilized to determine the relative positions of satellites. Laser data is used solely or together with GPS measurements. Numerical simulations were conducted to compare the relative navigation algorithm using only laser data and laser data combined with GPS data. If an accurate direction of laser pointing is estimated, the relative position of satellites can be determined using only laser measurements. If not, the combined algorithm has better performance, and is irrelevant to the precision of the relative angle data between two satellites in spherical coordinates. Within 10 km relative distance between satellites, relative navigation using double difference GPS data makes more precise relative position estimation results. If the simulation results are applied to the relative navigation strategy, the proper algorithm can be chosen, and the relative position of satellites can be estimated precisely in changing mission environments.

다목적 안과용 레이저 시스템 안전성 성능평가 및 임상적 유효성평가 가이드라인 수립을 위한 연구 (A Study on Safety, Performance and Clinical effectiveness Test Guideline of Versatile Ophthalmic Laser System)

  • 김유림;유우진;박호준;장원석
    • 대한의용생체공학회:의공학회지
    • /
    • 제40권6호
    • /
    • pp.250-259
    • /
    • 2019
  • Ophthalmic Laser System is widely used in Selective Laser Trabeculoplasty of Open Angle Glaucoma and Ocular Hypertension. Versatile ophthalmic laser system is a medical device with technology that checks the condition of the treatment area by irradiating a continuous laser pulse on the treatment area, and monitoring the microbubble reaction caused by the temperature increase of the melanosome through the ultrasonic signal and the optical signal sensor. It performs selective laser treatment without damaging the photoreceptor by controlling the wavelength of the laser when microbubbles are detected. This study aims to suggest a guideline for evaluating safety, performance and clinical effectiveness of Versatile Ophthalmic Laser System in accordance with the growing technology. International Standards, Regulations, and Clinical Trial Protocols were investigated and analyzed for this study. As a result of this study, the safety, performance and clinical effectiveness test guideline for Versatile Ophthalmic Laser System were proposed. This guideline will ensure the safety and efficacy of Medical device, and furthermore it is expected to be able to promote the development of technology development by supporting a clinical trial plan.

Cutting Technique for Biodegradable Rope using a CW CO2 Laser with TEM00 mode

  • Lee, Dong-Gil;Kim, Seong-Hun;Park, Seong-Wook;Yang, Yong-Su;Xu, Guo-Cheng
    • Journal of Electrical Engineering and Technology
    • /
    • 제7권4호
    • /
    • pp.576-581
    • /
    • 2012
  • A 23 W continuous wavelength $CO_2$ laser system exited by a high-frequency LCC resonant converter is adapted to cut a biodegradable rope fabricated with polybutylene succinate. As the biodegradable rope consists of three twisted strands, the thickness changes relative to the position of the laser beam and we thus propose a method to determine exact cutting depth. In order to obtain the parameters related to the rope cutting, the experimental and theoretical cutting depths are compared and analyzed for a range of laser heat sources. The melted thickness and groove width of the cut biodegradable rope are also examined. The proposed theoretical cutting depth depends on the incident power and target velocity ratio. From these experimental results, the biodegradable rope with a diameter of 22 mm can be cut with a heat source of 50 J/cm resulting in a melted thickness of 1.96 mm and a groove width of 0.65 mm. The laser system is shown to be perfect tool for the processing of biodegradable rope without the occurrence of raveling.

레이저스캐너를 이용한 차량저속운전보조장치의 설계 (Design of Vehicle Low speed Drive Assistant System with Laser Scanner)

  • 문희창;손영진;김정하
    • 제어로봇시스템학회논문지
    • /
    • 제14권8호
    • /
    • pp.856-864
    • /
    • 2008
  • This paper describes a vehicle low speed driving assistant (VLDA) system that is composed of laser scanner. This vehicle is designed for following lead vehicle (LV) without driver's operation. The system is made up several component systems that are based on unmanned ground vehicle (UGV). Each component system is applied to use advanced safety vehicle developed to complete UGV system. VLDA system was divided into vehicle control system and obstacle detecting system. The obstacle detecting system calculate distance and angle of LV and transmit these data to vehicle control system using front, left and right laser scanners. Vehicle control system makes vehicle control values such as steering angle, acceleration and brake position and control vehicle's movement with steering, acceleration and brake actuators. In this research, we designed VLDA system like as low speed cruise control system and test it on real road environments.