Welcome to LEAL

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  Laser Engineering & Applications Laboratory (LEAL), led by Dr Yoonchan Jeong, explores the outer reaches of photonics science and technology, especially, in high-power and high-energy regimes. The research foci are on developing innovative lasers and photonic systems and also on providing novel and powerful solutions to the related applications. The main research interests include Generation of High-Power / High-Energy Photons, Photon-Photon / Photon-Electron / Photon-Phonon Energy Conversions, Photon-Molecule Interactions, and related many interesting applications, such as Lidar, Laser Sonar, Remote Sensing, Space Optical Communication, Display, Nano-Biomedical applications, Technology Textiles, etc.

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News

  • Article "Spatio-Temporal Analysis on Shot-to- Shot Coherence and Wave-Packet Formation in Quasi-Mode Locked Regimes in Anomalous Dispersion Fiber Ring Cavity" written by Seungjong Lee and Yoonchan Jeong is featured on "Advances in Engineering".


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  • Professor Jeong received the best lecturer award for Fall 2017.

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  • Our lab got new student Minsu Yeo, Hyukjin Yang, Hyungu Kang.

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  • LEAL awards ceremony was held on Feb. 18.

  • Research professor Luis Alonso Vazquez-Zuniga got a new job at Calmar Laser and received a certification of apreaciation from Y. Jeong.

  • Our student S. Lee received the best student paper award for COOC 2016 conference.

  • Professor Jeong received the best lecturer award for Spring 2015.

  • Our student Y. Kwon received the best student paper award for COOC 2014 conference.

  • "Adaptive broadband continuum source at 1200-1400nm based on an all-fiber dual-wavelength master- oscillator power amplifier and a high-birefringence fiber" is posted to the OCT news article.

  • "Adaptive broadband continuum source at 1200-1400nm based on an all-fiber dual-wavelength master- oscillator power amplifier and a high-birefringence fiber" is also selected as the paper of the Virtual Journal of Biomedical Optics.

  • Our student K.Park received the best student paper award for ALTA 2013 conference.



Numerical and Experimental Study on Multi-Focal Metallic Fresnel Zone Plates Designed by the Phase Selection Rule via Virtual Point Sources


Jinseob Kim, Hyuntai Kim, Gun-Yeal Lee, Juhwan Kim, Byoungho Lee and Yoonchan Jeong

Vol 8, no.3, pp. 449-459, (2018), Applied Sciences

 

 Abstract :  We propose a novel design method for multi-focal metallic Fresnel zone plates (MFZPs), which exploits the phase selection rule by putting virtual point sources (VPSs) at the desired focal points distant to the MFZP plane. The phase distribution at the MFZP plane reciprocally formed by the VPSs was quantized in a binary manner based on the phase selection rule, thereby leading to a corresponding on-off amplitude pattern for the targeted MFZP. The resultant phase distribution was dependent on the complex amplitudes of the VPSs, so that they could be determined from the perspective of both multi-focal functionality and fabrication feasibility. As a typical example, we utilized the particle swarm optimization algorithm to determine them. Based on the proposed method, we designed and numerically analyzed two types of novel MFZPs—one for a monochromatic multi-focal application and the other for a multi-chromatic mono-focal application—verifying the effectiveness and validity of the proposed method. We also fabricated them onto Au-deposited glass substrates, using electron beam evaporation and a focused ion beam milling process. We experimentally characterized them and also verified that they successfully demonstrated their feasibilities. The former produced distinct hot spots at three different focal distances of 10, 15, and 20 µm for monochromatic incidence at 650 nm, and the latter produced a single hot spot at a focal distance of 15 µm for multi-chromatic incidence at 660, 532, and 473 nm. The experimental results were also in good agreement with their corresponding numerical results. We expect that both MFZPs will have various applications, such as laser micromachining, optical trapping, biomedical sensing, confocal collimation, achromatic optics, etc.

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